Item 8. FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA

Report of Independent Registered Public Accounting Firm

To the Board of Directors and Shareholders

of Ameren Corporation:

In our opinion, the consolidated financial statements listed in the index appearing under Item 15(a)(1) present fairly, in all material respects, the financial position of Ameren Corporation and its subsidiaries at December 31, 2015 and 2014, and the results of their operations and their cash flows for each of the three years in the period ended December 31, 2015, in conformity with accounting principles generally accepted in the United States of America. In addition, in our opinion, the financial statement schedules listed in the index appearing under Item 15(a)(2) present fairly, in all material respects, the information set forth therein when read in conjunction with the related consolidated financial statements. Also, in our opinion, the Company maintained, in all material respects, effective internal control over financial reporting as of December 31, 2015, based on criteria established in Internal Control – Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission (COSO). The Company’s management is responsible for these financial statements and financial statement schedules, for maintaining effective internal control over financial reporting and for its assessment of the effectiveness of internal control over financial reporting, included in Management’s Report on Internal Control over Financial Reporting appearing under Item 9A. Our responsibility is to express opinions on these financial statements, on the financial statement schedules, and on the Company’s internal control over financial reporting based on our integrated audits. We conducted our audits in accordance with the standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audits to obtain reasonable assurance about whether the financial statements are free of material misstatement and whether effective internal control over financial reporting was maintained in all material respects. Our audits of the financial statements included examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements, assessing the accounting principles used and significant estimates made by management, and evaluating the overall financial statement presentation. Our audit of internal control over financial reporting included obtaining an understanding of internal control over financial reporting, assessing the risk that a material weakness exists, and testing and evaluating the design and operating effectiveness of internal control based on the assessed risk. Our audits also included performing such other procedures as we considered necessary in the circumstances. We believe that our audits provide a reasonable basis for our opinions.

A company’s internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles. A company’s internal control over financial reporting includes those policies and procedures that (i) pertain to the maintenance of records that, in reasonable detail, accurately and fairly reflect the transactions and dispositions of the assets of the company; (ii) provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that receipts and expenditures of the company are being made only in accordance with authorizations of management and directors of the company; and (iii) provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use, or disposition of the company’s assets that could have a material effect on the financial statements.

Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

/s/PricewaterhouseCoopers LLP

PricewaterhouseCoopers LLP

St. Louis, Missouri

February 26, 2016

Report of Independent Registered Public Accounting Firm

To the Board of Directors and Shareholders

of Union Electric Company:

In our opinion, the financial statements listed in the index appearing under Item 15(a)(1) present fairly, in all material respects, the financial position of Union Electric Company at December 31, 2015 and 2014, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2015, in conformity with accounting principles generally accepted in the United States of America. In addition, in our opinion, the financial statement schedule listed in the index appearing under Item 15(a)(2) presents fairly, in all material respects, the information set forth therein when read in conjunction with the related financial statements. These financial statements and financial statement schedule are the responsibility of the Company’s management. Our responsibility is to express an opinion on these financial statements and financial statement schedule based on our audits. We conducted our audits of these statements in accordance with the standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the

audit to obtain reasonable assurance about whether the financial statements are free of material misstatement. An audit includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements, assessing the accounting principles used and significant estimates made by management, and evaluating the overall financial statement presentation. We believe that our audits provide a reasonable basis for our opinion.

/s/PricewaterhouseCoopers LLP

PricewaterhouseCoopers LLP

St. Louis, Missouri

February 26, 2016

Report of Independent Registered Public Accounting Firm

To the Board of Directors and Shareholders

of Ameren Illinois Company:

In our opinion, the financial statements listed in the index appearing under Item 15(a)(1) present fairly, in all material respects, the financial position of Ameren Illinois Company at December 31, 2015 and 2014, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2015, in conformity with accounting principles generally accepted in the United States of America. In addition, in our opinion, the financial statement schedule listed in the index appearing under Item 15(a)(2) presents fairly, in all material respects, the information set forth therein when read in conjunction with the related financial statements. These financial statements and financial statement schedule are the responsibility of the Company’s management. Our responsibility is to express an opinion on these financial statements and financial statement schedule based on our audits. We conducted our audits of these statements in accordance with the standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement. An audit includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements, assessing the accounting principles used and significant estimates made by management, and evaluating the overall financial statement presentation. We believe that our audits provide a reasonable basis for our opinion.

/s/PricewaterhouseCoopers LLP

PricewaterhouseCoopers LLP

St. Louis, Missouri

February 26, 2016

AMEREN CORPORATION CONSOLIDATED STATEMENT OF INCOME (In millions, except per share amounts)
	Year Ended December 31,
	2015				2014				2013
Operating Revenues:
Electric	$	5,180			$	4,913			$	4,832
Gas	918				1,140				1,006
Total operating revenues	6,098				6,053				5,838
Operating Expenses:
Fuel	878				826				845
Purchased power	514				461				508
Gas purchased for resale	415				615				526
Other operations and maintenance	1,694				1,684				1,611
Provision for Callaway construction and operating license (Note 2)	69				—				—
Depreciation and amortization	796				745				706
Taxes other than income taxes	473				468				458
Total operating expenses	4,839				4,799				4,654
Operating Income	1,259				1,254				1,184
Other Income and Expenses:
Miscellaneous income	74				79				69
Miscellaneous expense	30				22				26
Total other income	44				57				43
Interest Charges	355				341				398
Income Before Income Taxes	948				970				829
Income Taxes	363				377				311
Income from Continuing Operations	585				593				518
Income (Loss) from Discontinued Operations, Net of Taxes (Note 16)	51				(1		)		(223		)
Net Income	636				592				295
Less: Net Income from Continuing Operations Attributable to Noncontrolling Interests	6				6				6
Net Income (Loss) Attributable to Ameren Common Shareholders:
Continuing Operations	579				587				512
Discontinued Operations	51				(1		)		(223		)
Net Income Attributable to Ameren Common Shareholders	$	630			$	586			$	289
Earnings (Loss) per Common Share – Basic:
Continuing Operations	$	2.39			$	2.42			$	2.11
Discontinued Operations	0.21				—				(0.92		)
Earnings per Common Share – Basic	$	2.60			$	2.42			$	1.19
Earnings (Loss) per Common Share – Diluted:
Continuing Operations	$	2.38			$	2.40			$	2.10
Discontinued Operations	0.21				—				(0.92		)
Earnings per Common Share – Diluted	$	2.59			$	2.40			$	1.18
Dividends per Common Share	$	1.655			$	1.610			$	1.600
Average Common Shares Outstanding – Basic	242.6				242.6				242.6
Average Common Shares Outstanding – Diluted	243.6				244.4				244.5

The accompanying notes are an integral part of these consolidated financial statements.

AMEREN CORPORATION CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME (In millions)
	Year Ended December 31,
	2015				2014				2013
Income from Continuing Operations	$	585			$	593			$	518
Other Comprehensive Income from Continuing Operations, Net of Taxes
Pension and other postretirement benefit plan activity, net of income taxes (benefit) of $3, $(7), and $16, respectively	6				(12		)		30
Comprehensive Income from Continuing Operations	591				581				548
Less: Comprehensive Income from Continuing Operations Attributable to Noncontrolling Interests	6				6				6
Comprehensive Income from Continuing Operations Attributable to Ameren Common Shareholders	585				575				542
Income (Loss) from Discontinued Operations, Net of Taxes	51				(1		)		(223		)
Other Comprehensive Loss from Discontinued Operations, Net of Income Taxes (Benefit) of $-, $-, and $(10), respectively	—				—				(18		)
Comprehensive Income (Loss) from Discontinued Operations	51				(1		)		(241		)
Less: Comprehensive Income from Discontinued Operations Attributable to Noncontrolling Interest	—				—				1
Comprehensive Income (Loss) from Discontinued Operations Attributable to Ameren Common Shareholders	51				(1		)		(242		)
Comprehensive Income Attributable to Ameren Common Shareholders	$	636			$	574			$	300

The accompanying notes are an integral part of these consolidated financial statements.

AMEREN CORPORATION CONSOLIDATED BALANCE SHEET (In millions, except per share amounts)
	December 31,
	2015				2014
ASSETS
Current Assets:
Cash and cash equivalents	$	292			$	5
Accounts receivable – trade (less allowance for doubtful accounts of $19 and $21, respectively)	388				423
Unbilled revenue	239				265
Miscellaneous accounts and notes receivable	98				81
Materials and supplies	538				524
Current regulatory assets	260				295
Other current assets	88				86
Assets of discontinued operations (Note 16)	14				15
Total current assets	1,917				1,694
Property and Plant, Net	18,799				17,424
Investments and Other Assets:
Nuclear decommissioning trust fund	556				549
Goodwill	411				411
Regulatory assets	1,382				1,582
Other assets	575				629
Total investments and other assets	2,924				3,171
TOTAL ASSETS	$	23,640			$	22,289
LIABILITIES AND EQUITY
Current Liabilities:
Current maturities of long-term debt	$	395			$	120
Short-term debt	301				714
Accounts and wages payable	777				711
Taxes accrued	43				46
Interest accrued	89				85
Current regulatory liabilities	80				106
Other current liabilities	379				434
Liabilities of discontinued operations (Note 16)	29				33
Total current liabilities	2,093				2,249
Long-term Debt, Net	6,880				6,085
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes, net	3,885				3,571
Accumulated deferred investment tax credits	60				64
Regulatory liabilities	1,905				1,850
Asset retirement obligations	618				396
Pension and other postretirement benefits	580				705
Other deferred credits and liabilities	531				514
Total deferred credits and other liabilities	7,579				7,100
Commitments and Contingencies (Notes 2, 10, and 15)
Ameren Corporation Shareholders’ Equity:
Common stock, $.01 par value, 400.0 shares authorized – shares outstanding of 242.6	2				2
Other paid-in capital, principally premium on common stock	5,616				5,617
Retained earnings	1,331				1,103
Accumulated other comprehensive loss	(3		)		(9		)
Total Ameren Corporation shareholders’ equity	6,946				6,713
Noncontrolling Interests	142				142
Total equity	7,088				6,855
TOTAL LIABILITIES AND EQUITY	$	23,640			$	22,289

The accompanying notes are an integral part of these consolidated financial statements.

AMEREN CORPORATION CONSOLIDATED STATEMENT OF CASH FLOWS (In millions)
	Year Ended December 31,
	2015				2014				2013
Cash Flows From Operating Activities:
Net income	$	636			$	592			$	295
Loss (Income) from discontinued operations, net of tax	(51		)		1				223
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Provision for Callaway construction and operating license	69				—				—
Depreciation and amortization	777				710				666
Amortization of nuclear fuel	97				81				71
Amortization of debt issuance costs and premium/discounts	22				22				24
Deferred income taxes and investment tax credits, net	369				451				410
Allowance for equity funds used during construction	(30		)		(34		)		(37		)
Stock-based compensation costs	24				25				27
Other	(10		)		(24		)		23
Changes in assets and liabilities:
Receivables	83				31				(60		)
Materials and supplies	(14		)		3				60
Accounts and wages payable	(2		)		10				81
Taxes accrued	(24		)		(44		)		(195		)
Regulatory assets and liabilities	94				(281		)		29
Assets, other	53				30				20
Liabilities, other	(56		)		(28		)		(14		)
Pension and other postretirement benefits	(9		)		(10		)		(28		)
Counterparty collateral, net	(7		)		22				41
Net cash provided by operating activities – continuing operations	2,021				1,557				1,636
Net cash provided (used in) by operating activities – discontinued operations	(4		)		(6		)		57
Net cash provided by operating activities	2,017				1,551				1,693
Cash Flows From Investing Activities:
Capital expenditures	(1,917		)		(1,785		)		(1,379		)
Nuclear fuel expenditures	(52		)		(74		)		(45		)
Purchases of securities – nuclear decommissioning trust fund	(363		)		(405		)		(214		)
Sales and maturities of securities – nuclear decommissioning trust fund	349				391				196
Proceeds from note receivable – Marketing Company	20				95				6
Contributions to note receivable – Marketing Company	(8		)		(89		)		(5		)
Other	20				11				1
Net cash used in investing activities – continuing operations	(1,951		)		(1,856		)		(1,440		)
Net cash provided by (used in) investing activities – discontinued operations	(25		)		139				(283		)
Net cash used in investing activities	(1,976		)		(1,717		)		(1,723		)
Cash Flows From Financing Activities:
Dividends on common stock	(402		)		(390		)		(388		)
Dividends paid to noncontrolling interest holders	(6		)		(6		)		(6		)
Short-term debt, net	(413		)		346				368
Maturities, redemptions and repurchases of long-term debt	(120		)		(697		)		(399		)
Issuances of long-term debt	1,197				898				278
Capital issuance costs	(12		)		(11		)		(2		)
Other	2				1				—
Net cash provided by (used in) financing activities – continuing operations	246				141				(149		)
Net change in cash and cash equivalents	287				(25		)		(179		)
Cash and cash equivalents at beginning of year	5				30				209
Cash and cash equivalents at end of year	$	292			$	5			$	30
Cash Paid (Refunded) During the Year:
Interest (net of $17, $18, and $37 capitalized, respectively)	$	335			$	333			$	393
Income taxes, net	(15		)		(27		)		8

The accompanying notes are an integral part of these consolidated financial statements.

AMEREN CORPORATION CONSOLIDATED STATEMENT OF SHAREHOLDERS’ EQUITY (In millions)
	December 31,
	2015				2014				2013
Common Stock:
Beginning of year	$	2			$	2			$	2
Shares issued	—				—				—
Common stock, end of year	2				2				2
Other Paid-in Capital:
Beginning of year	5,617				5,632				5,616
Stock-based compensation activity	(1		)		(15		)		16
Other paid-in capital, end of year	5,616				5,617				5,632
Retained Earnings:
Beginning of year	1,103				907				1,006
Net income attributable to Ameren common shareholders	630				586				289
Dividends	(402		)		(390		)		(388		)
Retained earnings, end of year	1,331				1,103				907
Accumulated Other Comprehensive Income (Loss):
Derivative financial instruments, beginning of year	—				—				25
Change in derivative financial instruments	—				—				(21		)
Divestiture of derivative financial instruments (Note 16)	—				—				(4		)
Derivative financial instruments, end of year	—				—				—
Deferred retirement benefit costs, beginning of year	(9		)		3				(33		)
Change in deferred retirement benefit costs	6				(12		)		29
Divestiture of deferred retirement benefit costs (Note 16)	—				—				7
Deferred retirement benefit costs, end of year	(3		)		(9		)		3
Total accumulated other comprehensive income (loss), end of year	(3		)		(9		)		3
Total Ameren Corporation Shareholders’ Equity	$	6,946			$	6,713			$	6,544
Noncontrolling Interests:
Beginning of year	142				142				151
Net income attributable to noncontrolling interest holders	6				6				6
Dividends paid to noncontrolling interest holders	(6		)		(6		)		(6		)
Divestiture of noncontrolling interest (Note 16)	—				—				(9		)
Noncontrolling interests, end of year	142				142				142
Total Equity	$	7,088			$	6,855			$	6,686
Common stock shares at end of year	242.6				242.6				242.6

The accompanying notes are an integral part of these consolidated financial statements.

UNION ELECTRIC COMPANY (d/b/a AMEREN MISSOURI) STATEMENT OF INCOME AND COMPREHENSIVE INCOME (In millions)
	Year Ended December 31,
	2015				2014				2013
Operating Revenues:
Electric	$	3,470			$	3,388			$	3,379
Gas	137				164				161
Other	2				1				1
Total operating revenues	3,609				3,553				3,541
Operating Expenses:
Fuel	878				826				845
Purchased power	111				126				133
Gas purchased for resale	57				82				78
Other operations and maintenance	925				939				909
Provision for Callaway construction and operating license (Note 2)	69				—				—
Depreciation and amortization	492				473				454
Taxes other than income taxes	335				322				319
Total operating expenses	2,867				2,768				2,738
Operating Income	742				785				803
Other Income and Expenses:
Miscellaneous income	52				60				58
Miscellaneous expense	11				12				11
Total other income	41				48				47
Interest Charges	219				211				210
Income Before Income Taxes	564				622				640
Income Taxes	209				229				242
Net Income	355				393				398
Other Comprehensive Income	—				—				—
Comprehensive Income	$	355			$	393			$	398
Net Income	$	355			$	393			$	398
Preferred Stock Dividends	3				3				3
Net Income Available to Common Shareholder	$	352			$	390			$	395

The accompanying notes as they relate to Ameren Missouri are an integral part of these financial statements.

UNION ELECTRIC COMPANY (d/b/a AMEREN MISSOURI) BALANCE SHEET (In millions, except per share amounts)
	December 31,
	2015				2014
ASSETS
Current Assets:
Cash and cash equivalents	$	199			$	1
Advances to money pool	36				—
Accounts receivable – trade (less allowance for doubtful accounts of $7 and $8, respectively)	174				190
Accounts receivable – affiliates	54				65
Unbilled revenue	128				146
Miscellaneous accounts and notes receivable	78				35
Materials and supplies	387				347
Current regulatory assets	89				163
Other current assets	41				43
Total current assets	1,186				990
Property and Plant, Net	11,183				10,867
Investments and Other Assets:
Nuclear decommissioning trust fund	556				549
Regulatory assets	605				695
Other assets	321				373
Total investments and other assets	1,482				1,617
TOTAL ASSETS	$	13,851			$	13,474
LIABILITIES AND SHAREHOLDERS’ EQUITY
Current Liabilities:
Current maturities of long-term debt	$	266			$	120
Short-term debt	—				97
Accounts and wages payable	417				405
Accounts payable – affiliates	56				56
Taxes accrued	31				32
Interest accrued	59				58
Current regulatory liabilities	28				18
Other current liabilities	120				117
Total current liabilities	977				903
Long-term Debt, Net	3,844				3,861
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes, net	2,844				2,757
Accumulated deferred investment tax credits	58				61
Regulatory liabilities	1,172				1,147
Asset retirement obligations	612				389
Pension and other postretirement benefits	234				274
Other deferred credits and liabilities	28				30
Total deferred credits and other liabilities	4,948				4,658
Commitments and Contingencies (Notes 2, 10, 14, and 15)
Shareholders’ Equity:
Common stock, $5 par value, 150.0 shares authorized – 102.1 shares outstanding	511				511
Other paid-in capital, principally premium on common stock	1,822				1,569
Preferred stock	80				80
Retained earnings	1,669				1,892
Total shareholders’ equity	4,082				4,052
TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY	$	13,851			$	13,474

The accompanying notes as they relate to Ameren Missouri are an integral part of these financial statements.

UNION ELECTRIC COMPANY (d/b/a AMEREN MISSOURI) STATEMENT OF CASH FLOWS (In millions)
	Year Ended December 31,
	2015				2014				2013
Cash Flows From Operating Activities:
Net income	$	355			$	393			$	398
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for Callaway construction and operating license	69				—				—
Depreciation and amortization	476				442				419
Amortization of nuclear fuel	97				81				71
FAC prudence review charges	—				—				26
Amortization of debt issuance costs and premium/discounts	6				7				7
Deferred income taxes and investment tax credits, net	82				245				65
Allowance for equity funds used during construction	(22		)		(32		)		(31		)
Other	2				3				1
Changes in assets and liabilities:
Receivables	72				(10		)		(59		)
Materials and supplies	(39		)		8				45
Accounts and wages payable	3				25				42
Taxes accrued	1				(197		)		100
Regulatory assets and liabilities	117				(68		)		68
Assets, other	26				52				18
Liabilities, other	4				—				(29		)
Pension and other postretirement benefits	(2		)		1				2
Net cash provided by operating activities	1,247				950				1,143
Cash Flows From Investing Activities:
Capital expenditures	(622		)		(747		)		(648		)
Nuclear fuel expenditures	(52		)		(74		)		(45		)
Purchases of securities – nuclear decommissioning trust fund	(363		)		(405		)		(214		)
Sales and maturities of securities – nuclear decommissioning trust fund	349				391				196
Money pool advances, net	(36		)		—				24
Other	—				(2		)		—
Net cash used in investing activities	(724		)		(837		)		(687		)
Cash Flows From Financing Activities:
Dividends on common stock	(575		)		(340		)		(460		)
Return of capital to parent	—				(215		)		—
Dividends on preferred stock	(3		)		(3		)		(3		)
Short-term debt, net	(97		)		97				—
Money pool borrowings, net	—				(105		)		105
Redemptions, repurchases, and maturities of long-term debt	(120		)		(109		)		(249		)
Issuances of long-term debt	249				350				—
Capital issuance costs	(3		)		(3		)		—
Capital contribution from parent	224				215				4
Net cash used in financing activities	(325		)		(113		)		(603		)
Net change in cash and cash equivalents	198				—				(147		)
Cash and cash equivalents at beginning of year	1				1				148
Cash and cash equivalents at end of year	$	199			$	1			$	1
Noncash financing activity – capital contribution from parent	$	38			$	9			$	—
Cash Paid (Refunded) During the Year:
Interest (net of $12, $16, and $16 capitalized, respectively)	$	212			$	203			$	212
Income taxes, net	72				215				86

The accompanying notes as they relate to Ameren Missouri are an integral part of these financial statements.

UNION ELECTRIC COMPANY (d/b/a AMEREN MISSOURI) STATEMENT OF SHAREHOLDERS’ EQUITY (In millions)
	December 31,
	2015				2014				2013
Common Stock	$	511			$	511			$	511
Other Paid-in Capital:
Beginning of year	1,569				1,560				1,556
Capital contribution from parent (Note 1)	253				224				4
Return of capital to parent (Note 1)	—				(215		)		—
Other paid-in capital, end of year	1,822				1,569				1,560
Preferred Stock	80				80				80
Retained Earnings:
Beginning of year	1,892				1,842				1,907
Net income	355				393				398
Common stock dividends	(575		)		(340		)		(460		)
Preferred stock dividends	(3		)		(3		)		(3		)
Retained earnings, end of year	1,669				1,892				1,842
Total Shareholders’ Equity	$	4,082			$	4,052			$	3,993

The accompanying notes as they relate to Ameren Missouri are an integral part of these financial statements.

AMEREN ILLINOIS COMPANY (d/b/a AMEREN ILLINOIS)

STATEMENT OF INCOME AND COMPREHENSIVE INCOME

(In millions)

	Year Ended December 31,
	2015				2014				2013
Operating Revenues:
Electric	$	1,683			$	1,522			$	1,461
Gas	783				976				847
Other	—				—				3
Total operating revenues	2,466				2,498				2,311
Operating Expenses:
Purchased power	420				343				380
Gas purchased for resale	358				533				448
Other operations and maintenance	797				771				693
Depreciation and amortization	295				263				243
Taxes other than income taxes	130				138				132
Total operating expenses	2,000				2,048				1,896
Operating Income	466				450				415
Other Income and Expenses:
Miscellaneous income	21				17				10
Miscellaneous expense	12				8				9
Total other income	9				9				1
Interest Charges	131				112				143
Income Before Income Taxes	344				347				273
Income Taxes	127				143				110
Net Income	217				204				163
Other Comprehensive Loss, Net of Taxes:
Pension and other postretirement benefit plan activity, net of income tax benefit of $(2), $(2), and $(2), respectively	(3		)		(3		)		(3		)
Comprehensive Income	$	214			$	201			$	160
Net Income	$	217			$	204			$	163
Preferred Stock Dividends	3				3				3
Net Income Available to Common Shareholder	$	214			$	201			$	160

The accompanying notes as they relate to Ameren Illinois are an integral part of these financial statements.

AMEREN ILLINOIS COMPANY (d/b/a AMEREN ILLINOIS) BALANCE SHEET (In millions)
	December 31,
	2015				2014
ASSETS
Current Assets:
Cash and cash equivalents	$	71			$	1
Accounts receivable – trade (less allowance for doubtful accounts of $12 and $13, respectively)	204				212
Accounts receivable – affiliates	22				22
Unbilled revenue	111				119
Miscellaneous accounts receivable	19				9
Materials and supplies	151				177
Current regulatory assets	167				129
Other current assets	15				15
Total current assets	760				684
Property and Plant, Net	6,848				6,165
Investments and Other Assets:
Goodwill	411				411
Regulatory assets	771				883
Other assets	113				61
Total investments and other assets	1,295				1,355
TOTAL ASSETS	$	8,903			$	8,204
LIABILITIES AND SHAREHOLDERS’ EQUITY
Current Liabilities:
Current maturities of long-term debt	$	129			$	—
Short-term debt	—				32
Borrowings from money pool	—				15
Accounts and wages payable	249				207
Accounts payable – affiliates	66				50
Taxes accrued	13				17
Customer deposits	69				77
Mark-to-market derivative liabilities	45				42
Current environmental remediation	28				52
Current regulatory liabilities	39				84
Other current liabilities	114				124
Total current liabilities	752				700
Long-term Debt, Net	2,342				2,224
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes, net	1,480				1,248
Accumulated deferred investment tax credits	2				3
Regulatory liabilities	732				703
Pension and other postretirement benefits	271				277
Environmental remediation	205				199
Other deferred credits and liabilities	222				189
Total deferred credits and other liabilities	2,912				2,619
Commitments and Contingencies (Notes 2, 14, and 15)
Shareholders’ Equity:
Common stock, no par value, 45.0 shares authorized – 25.5 shares outstanding	—				—
Other paid-in capital	2,005				1,980
Preferred stock	62				62
Retained earnings	825				611
Accumulated other comprehensive income	5				8
Total shareholders’ equity	2,897				2,661
TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY	$	8,903			$	8,204

The accompanying notes as they relate to Ameren Illinois are an integral part of these financial statements.

AMEREN ILLINOIS COMPANY (d/b/a AMEREN ILLINOIS) STATEMENT OF CASH FLOWS (In millions)
	Year Ended December 31,
	2015				2014				2013
Cash Flows From Operating Activities:
Net income	$	217			$	204			$	163
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	292				259				238
Amortization of debt issuance costs and premium/discounts	14				13				15
Deferred income taxes and investment tax credits, net	221				196				104
Other	(14		)		(19		)		4
Changes in assets and liabilities:
Receivables	16				(13		)		50
Materials and supplies	25				(4		)		15
Accounts and wages payable	37				7				19
Taxes accrued	(2		)		(7		)		28
Regulatory assets and liabilities	(26		)		(215		)		(35		)
Assets, other	17				15				5
Liabilities, other	(27		)		1				10
Pension and other postretirement benefits	(4		)		(6		)		(8		)
Counterparty collateral, net	(3		)		14				43
Net cash provided by operating activities	763				445				651
Cash Flows From Investing Activities:
Capital expenditures	(918		)		(835		)		(701		)
Other	5				7				6
Net cash used in investing activities	(913		)		(828		)		(695		)
Cash Flows From Financing Activities:
Dividends on common stock	—				—				(110		)
Dividends on preferred stock	(3		)		(3		)		(3		)
Short-term debt, net	(32		)		32				—
Money pool borrowings, net	(15		)		(41		)		32
Redemptions, repurchases, and maturities of long-term debt	—				(163		)		(150		)
Issuances of long-term debt	248				548				278
Capital issuance costs	(3		)		(6		)		(2		)
Capital contribution from parent	25				15				—
Other	—				1				—
Net cash provided by financing activities	220				383				45
Net change in cash and cash equivalents	70				—				1
Cash and cash equivalents at beginning of year	1				1				—
Cash and cash equivalents at end of year	$	71			$	1			$	1
Cash Paid (Refunded) During the Year:
Interest (net of $5, $2, and $4 capitalized, respectively)	$	120			$	110			$	112
Income taxes, net	(113		)		(44		)		(23		)

The accompanying notes as they relate to Ameren Illinois are an integral part of these financial statements.

AMEREN ILLINOIS COMPANY (d/b/a AMEREN ILLINOIS) STATEMENT OF SHAREHOLDERS’ EQUITY (In millions)
	December 31,
	2015				2014				2013
Common Stock	$	—			$	—			$	—
Other Paid-in Capital
Beginning of year	1,980				1,965				1,965
Capital contribution from parent (Note 1)	25				15				—
Other paid-in capital, end of year	2,005				1,980				1,965
Preferred Stock	62				62				62
Retained Earnings:
Beginning of year	611				410				360
Net income	217				204				163
Common stock dividends	—				—				(110		)
Preferred stock dividends	(3		)		(3		)		(3		)
Retained earnings, end of year	825				611				410
Accumulated Other Comprehensive Income:
Deferred retirement benefit costs, beginning of year	8				11				14
Change in deferred retirement benefit costs	(3		)		(3		)		(3		)
Deferred retirement benefit costs, end of year	5				8				11
Total accumulated other comprehensive income, end of year	5				8				11
Total Shareholders’ Equity	$	2,897			$	2,661			$	2,448

The accompanying notes as they relate to Ameren Illinois are an integral part of these financial statements.

AMEREN CORPORATION (Consolidated)

UNION ELECTRIC COMPANY (d/b/a Ameren Missouri)

AMEREN ILLINOIS COMPANY (d/b/a Ameren Illinois)

COMBINED NOTES TO FINANCIAL STATEMENTS December 31, 2015

NOTE 1 – SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

General

Ameren, headquartered in St. Louis, Missouri, is a public utility holding company under PUHCA 2005. Ameren’s primary assets are its equity interests in its subsidiaries, including Ameren Missouri and Ameren Illinois. Ameren’s subsidiaries are separate, independent legal entities with separate businesses, assets, and liabilities. Dividends on Ameren’s common stock and the payment of expenses by Ameren depend on distributions made to it by its subsidiaries. Ameren’s principal subsidiaries are listed below.

•

Union Electric Company, doing business as Ameren Missouri, operates a rate-regulated electric generation, transmission, and distribution business and a rate-regulated natural gas transmission and distribution business in Missouri. Ameren Missouri was incorporated in Missouri in 1922 and is successor to a number of companies, the oldest of which was organized in 1881. It is the largest electric utility in the state of Missouri. It supplies electric and natural gas service to a 24,000-square-mile area in central and eastern Missouri. This area has an estimated population of 2.8 million and includes the Greater St. Louis area. Ameren Missouri supplies electric service to 1.2 million customers and natural gas service to 0.1 million customers.

•

Ameren Illinois Company, doing business as Ameren Illinois, operates rate-regulated electric and natural gas transmission and distribution businesses in Illinois. Ameren Illinois was created by the merger of CILCO and IP with and into CIPS in 2010. CIPS was incorporated in Illinois in 1923 and was the successor to a number of companies, the oldest of which was organized in 1902. Ameren Illinois supplies electric and natural gas utility service to portions of central and southern Illinois having an estimated population of 3.1 million in an area of 40,000 square miles. Ameren Illinois supplies electric service to 1.2 million customers and natural gas service to 0.8 million customers.

Ameren has various other subsidiaries that conduct activities such as the provision of shared services. Ameren also has a subsidiary, ATXI, that operates a FERC rate-regulated electric transmission business. ATXI is developing MISO-approved electric transmission projects, including the Illinois Rivers, Spoon River, and Mark Twain projects. Ameren is also pursuing projects to improve electric transmission system reliability within Ameren Missouri's and Ameren Illinois' service territories as well as competitive electric transmission investment opportunities outside of these territories, including investments outside of MISO.

In December 2013, Ameren completed the divestiture of

New AER to IPH. In January 2014, Medina Valley completed its sale of the Elgin, Gibson City, and Grand Tower gas-fired energy centers to Rockland Capital. In addition, in 2013, Ameren abandoned the Meredosia and Hutsonville energy centers upon the completion of the divestiture of New AER to IPH. Ameren is demolishing the Hutsonville energy center and expects to demolish the Meredosia energy center beginning in 2016. As a result of these events, Ameren has segregated New AER’s and the Elgin, Gibson City, Grand Tower, Meredosia, and Hutsonville energy centers’ operating results, assets, and liabilities and presented them separately as discontinued operations for all periods presented in this report. Unless otherwise stated, these notes to the financial statements exclude discontinued operations for all periods presented. See Note 16 – Divestiture Transactions and Discontinued Operations for additional information regarding these transactions.

Ameren's financial statements are prepared on a consolidated basis, and therefore include the accounts of its majority-owned subsidiaries. Ameren Missouri and Ameren Illinois have no subsidiaries and therefore their financial statements are not prepared on a consolidated basis. All intercompany transactions have been eliminated. All tabular dollar amounts are in millions, unless otherwise indicated.

Our accounting policies conform to GAAP. Our financial statements reflect all adjustments (which include normal, recurring adjustments) that are necessary, in our opinion, for a fair presentation of our results. The preparation of financial statements in conformity with GAAP requires management to make certain estimates and assumptions. Such estimates and assumptions affect reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the dates of financial statements, and the reported amounts of revenues and expenses during the reported periods. Actual results could differ from those estimates.

Regulation

We are regulated by the MoPSC, the ICC, and the FERC. We defer certain costs as assets pursuant to actions of rate regulators or because of expectations that we will be able to recover such costs in future rates charged to customers. We also defer certain amounts as liabilities pursuant to actions of rate regulators or based on the expectation that such amounts will be returned to customers in future rates. Regulatory assets and liabilities are amortized consistent with the period of expected regulatory treatment. In addition to the cost recovery mechanisms discussed in the Purchased Gas, Power, and Fuel Rate-adjustment Mechanisms section below, Ameren Missouri and Ameren Illinois have approvals from rate regulators to use other cost recovery mechanisms. Ameren Missouri has a pension and postretirement benefit cost tracker, an uncertain tax positions tracker, a renewable energy standards cost tracker, a solar rebate program tracker, and the MEEIA energy efficiency rider. Ameren Illinois' and ATXI's electric transmission rates are determined pursuant to formula ratemaking. Additionally, Ameren Illinois' electric distribution business participates in the performance-based formula ratemaking process established

pursuant to the IEIMA. Ameren Illinois also has an environmental cost rider, an asbestos-related litigation rider, an energy efficiency rider, a QIP rider, a VBA rider, and a bad debt rider. See Note 2 – Rate and Regulatory Matters for additional information on regulatory assets and liabilities.

Cash and Cash Equivalents

Cash and cash equivalents include cash on hand and temporary investments purchased with an original maturity of three months or less.

Allowance for Doubtful Accounts Receivable

The allowance for doubtful accounts represents our estimate of existing accounts receivable that will ultimately be uncollectible. The allowance is calculated by applying estimated loss factors to various classes of outstanding receivables, including unbilled revenue. The loss factors used to estimate uncollectible accounts are based upon both historical collections experience and management’s estimate of future collections success given the existing and anticipated future collections environment. Ameren Illinois has a bad debt rider that adjusts rates for net write-offs of customer accounts receivable above or below those being collected in rates.

Materials and Supplies

Materials and supplies are recorded at the lower of cost or market. Cost is determined by the average-cost method. Materials and supplies are capitalized as inventory when purchased and then expensed or capitalized as plant assets when installed, as appropriate. The following table presents a breakdown of materials and supplies for each of the Ameren Companies at December 31, 2015 and 2014:

		Ameren Missouri				Ameren Illinois				Ameren
2015
Fuel(a)		$	173			$	—			$	173
Gas stored underground		10				87				97
Other materials and supplies		204				64				268
Total materials and supplies		$	387			$	151			$	538
2014
Fuel(a)		$	134			$	—			$	134
Gas stored underground		16				111				127
Other materials and supplies		197				66				263
Total materials and supplies		$	347			$	177			$	524

(a)	Consists of coal, oil, and propane.

Purchased Gas, Power and Fuel Rate-adjustment Mechanisms

Ameren Missouri and Ameren Illinois have various rate-adjustment mechanisms in place that provide for the recovery of purchased natural gas and electric fuel and purchased power costs without a traditional rate case proceeding. See Note 2 – Rate and Regulatory Matters for the regulatory assets and liabilities recorded at December 31, 2015 and 2014, related to the rate-adjustment mechanisms discussed below.

In Ameren Missouri’s and Ameren Illinois’ natural gas utility jurisdictions, changes in natural gas costs are reflected in billings to their natural gas utility customers through PGA clauses. The difference between actual natural gas costs and costs billed to customers in a given period is deferred as a regulatory asset or liability. The deferred amount is either billed or refunded to natural gas utility customers in a subsequent period.

In Ameren Illinois’ retail electric utility jurisdiction, changes in purchased power and transmission service costs are reflected in billings to its electric utility customers through pass-through rate-adjustment clauses. The difference between actual purchased power and transmission service costs and costs billed to customers in a given period is deferred as a regulatory asset or liability. The deferred amount is either billed or refunded to electric utility customers in a subsequent period.

Ameren Missouri has a FAC that allows an adjustment of electric rates three times per year for a pass-through to customers of 95% of changes in fuel and purchased power costs, including transportation charges and revenues, net of off-system sales, greater or less than the amount set in base rates, subject to MoPSC prudence review. The difference between the actual amounts incurred for these items and the amounts recovered from Ameren Missouri customers' base rates is deferred as a regulatory asset or liability. The deferred amounts are either billed or refunded to electric utility customers in a subsequent period. As of May 30, 2015, transmission revenues and substantially all transmission charges are excluded from net energy costs as a result of the April 2015 MoPSC electric rate order.

Property and Plant, Net

We capitalize the cost of additions to and betterments of units of property and plant. The cost includes labor, material, applicable taxes, and overhead. An allowance for funds used during construction, as discussed below, is also capitalized as a cost of our rate-regulated assets. Maintenance expenditures, including nuclear refueling and maintenance outages, are expensed as incurred. When units of depreciable property are retired, the original costs, less salvage values, are charged to accumulated depreciation. If environmental expenditures are related to assets currently in use, as in the case of the installation

of pollution control equipment, the cost is capitalized and depreciated over the expected life of the asset. See Asset Retirement Obligations below and Note 3 – Property and Plant, Net, for additional information.

Depreciation

Depreciation is provided over the estimated lives of the various classes of depreciable property by applying composite rates on a straight-line basis to the cost basis of such property. The provision for depreciation for the Ameren Companies in 2015, 2014, and 2013 ranged from 3% to 4% of the average depreciable cost.

Allowance for Funds Used During Construction

We capitalize allowance for funds used during construction, or the cost of borrowed funds and the cost of equity funds (preferred and common shareholders’ equity) applicable to rate-regulated construction expenditures, in accordance with the utility industry's accounting practice. Allowance for funds used during construction does not represent a current source of cash funds. This accounting practice offsets the effect on earnings of the cost of financing during construction, and it treats such financing costs in the same manner as construction charges for labor and materials.

Under accepted ratemaking practice, cash recovery of allowance for funds used during construction and other construction costs occurs when completed projects are placed in service and reflected in customer rates. The following table presents the annual allowance for funds used during construction rates that were applied to construction projects in 2015, 2014, and 2013:

	2015			2014			2013
Ameren Missouri	7	%		7	%		8	%
Ameren Illinois	6	%		2	%		8	%

Goodwill

Goodwill represents the excess of the purchase price of an acquisition over the fair value of the net assets acquired. Ameren and Ameren Illinois' carrying amount of goodwill was $411 million at December 31, 2015, and 2014. All of Ameren's and Ameren Illinois' goodwill at December 31, 2015 and 2014, was assigned to the Ameren Illinois reporting unit.

We evaluate goodwill for impairment as of October 31 each year, or more frequently if events and circumstances change that would more likely than not reduce the fair value of the Ameren Illinois reporting unit below its carrying amount. Entities assessing goodwill for impairment have the option of first performing a qualitative assessment before calculating the fair value of the reporting unit. If an entity determines, on the basis of qualitative factors, that the fair value of the reporting unit is more likely than not less than the carrying amount, a two-step quantitative test is required. An entity has the option to bypass the qualitative assessment in any period and proceed directly to

the first step of the quantitative test, which compares the fair value of the reporting unit to its carrying amount. If the carrying amount of the reporting unit exceeds its estimated fair value, the entity performs the second step, which requires an assignment of the reporting unit's fair value to the individual assets and liabilities in order to determine the implied fair value of the reporting unit's goodwill. If the implied fair value of goodwill is less than its carrying amount, an impairment loss is recorded.

Ameren and Ameren Illinois elected to bypass the qualitative assessment and completed the first step of the quantitative test as of October 31, 2015. Based on the results, Ameren and Ameren Illinois determined that the estimated fair value of the Ameren Illinois reporting unit significantly exceeded its carrying value as of October 31, 2015, indicating no impairment of Ameren’s or Ameren Illinois’ goodwill. Ameren's and Ameren Illinois' valuation approach is based on a market participant view. It uses a weighted combination of a discounted cash flow analysis and a market multiples analysis. Significant assumptions used in estimating the fair value of the Ameren Illinois reporting unit include discount and growth rates, utility sector market performance and transactions, and projected operating results and cash flows.

The goodwill assigned to the Ameren Illinois reporting unit on the December 31, 2015 balance sheets of Ameren and Ameren Illinois had no accumulated goodwill impairment losses. Ameren and Ameren Illinois will continue to monitor internal and external factors for signs of possible declines in estimated fair value and potential goodwill impairment.

Impairment of Long-lived Assets

We evaluate long-lived assets classified as held and used for impairment when events or changes in circumstances indicate that the carrying value of such assets may not be recoverable. Whether an impairment has occurred is determined by comparing the estimated undiscounted cash flows attributable to the assets to the carrying value of the assets. If the carrying value exceeds the undiscounted cash flows, we recognize an impairment charge equal to the amount by which the carrying value exceeds the estimated fair value of the assets. In the period in which we determine an asset meets held for sale criteria, we record an impairment charge to the extent the book value exceeds its estimated fair value less cost to sell. We did not identify any events or changes in circumstances that indicated that the carrying value of long-lived assets may not be recoverable in 2015 and 2014.

Environmental Costs

Liabilities for environmental costs are recorded on an undiscounted basis when it is probable that a liability has been incurred and the amount of the liability can be reasonably estimated. Costs are expensed or deferred as a regulatory asset when it is expected that the costs will be recovered from customers in future rates.

Asset Retirement Obligations

We are required to record the estimated fair value of legal obligations associated with the retirement of tangible long-lived assets in the period in which the liabilities are incurred and to capitalize a corresponding amount as part of the book value of the related long-lived asset. In subsequent periods, we are required to make adjustments to AROs based on changes in the estimated fair values of the obligations. Corresponding increases in asset book values are depreciated over the remaining useful life of the related asset. Uncertainties as to the probability, timing, or amount of cash expenditures associated with AROs affect our estimates of fair value. Ameren and Ameren Missouri have recorded AROs for retirement costs associated with Ameren Missouri’s Callaway energy center decommissioning costs, CCR facilities, and river structures. Also, Ameren, Ameren Missouri, and Ameren Illinois have recorded AROs for retirement costs associated with asbestos removal and the disposal of certain transformers. Ameren and Ameren Missouri have a nuclear decommissioning trust fund for the decommissioning of the Callaway energy center. Asset removal costs accrued by our rate-regulated operations that do not constitute legal obligations are classified as regulatory liabilities. See Note 2 – Rate and Regulatory Matters.

The following table provides a reconciliation of the beginning and ending carrying amount of AROs for the years ended December 31, 2015 and 2014:

	Ameren Missouri				Ameren Illinois				Ameren
Balance at December 31, 2013	$	366			$	3			$	369
Liabilities incurred	2				—				2
Liabilities settled	(2		)		(a)				(2		)
Accretion in 2014(b)	21				(a)				21
Change in estimates(c)	2				4				6
Balance at December 31, 2014	$	389			$	7		(d)	$	396
Liabilities incurred	3				—				3
Liabilities settled	(1		)		(1		)		(2		)
Accretion in 2015(b)	23				(a)				23
Change in estimates(e)	203				(a)				203
Balance at December 31, 2015	$	617		(f)	$	6		(d)	$	623		(f)

(a)	Less than $1 million.

(b)	Accretion expense was recorded as an increase to regulatory assets at Ameren Missouri and Ameren Illinois.

(c)	The ARO increase resulted in a corresponding increase recorded to "Property and Plant, Net." Ameren Illinois changed its fair value estimate for asbestos removal.

(d)	Included in “Other deferred credits and liabilities” on the balance sheet.

(e)

The ARO increase resulted in a corresponding increase recorded to "Property and Plant, Net." Ameren and Ameren Missouri increased their AROs related to the decommissioning of the Callaway energy center by $99 million to reflect the 2015 cost study and funding analysis filed with the MoPSC, the extension of the estimated operating life until 2044, and a reduction in the discount rate assumption. See Note 10 – Callaway Energy Center for additional information. In addition, as a result of new federal regulations, Ameren and Ameren Missouri recorded an increase of $100 million to their AROs associated with CCR storage facilities. See Note 15 – Commitments and Contingencies for additional information. Ameren and Ameren Missouri also increased their AROs by $4 million due to a change in the estimated retirement dates of the Meramec and Rush Island energy centers as a result of the MoPSC's April 2015 electric rate order.

(f)	Balance included $5 million in "Other current liabilities" on the balance sheet as of December 31, 2015.

See Note 16 – Divestiture Transactions and Discontinued Operations for additional information on the AROs related to the abandoned Meredosia and Hutsonville energy centers, which are presented as discontinued operations and therefore not included in the table above.

Noncontrolling Interests

As of December 31, 2015 and 2014, Ameren’s noncontrolling interests included the preferred stock of Ameren Missouri and Ameren Illinois.

Operating Revenue

The Ameren Companies record operating revenue for electric or natural gas service when it is delivered to customers. We accrue an estimate of electric and natural gas revenues for service rendered but unbilled at the end of each accounting period.

Ameren Illinois participates in the performance-based formula ratemaking framework pursuant to the IEIMA. In addition, Ameren Illinois' and ATXI's electric transmission delivery service operating revenues are regulated by the FERC. The provisions of

the IEIMA and the FERC's electric transmission formula rate framework provide for annual reconciliations of the electric delivery and electric transmission service revenue requirements necessary to reflect the actual recoverable costs incurred in a given year with the revenue requirements in customer rates for that year, including an allowed return on equity. In each of those electric jurisdictions, if the current year's revenue requirement is greater than the revenue requirement reflected in that year's customer rates, an increase to electric operating revenues with an offset to a regulatory asset is recorded to reflect the expected recovery of those additional amounts from customers within the next two years. In each jurisdiction, if the current year's revenue requirement is less than the revenue requirement reflected in that year's customer rates, a reduction to electric operating revenues with an offset to a regulatory liability is recorded to reflect the expected refund to customers within the next two years. See Note 2 – Rate and Regulatory Matters for information regarding

Ameren Illinois' revenue requirement reconciliation pursuant to the IEIMA.

Accounting for MISO Transactions

MISO-related purchase and sale transactions are recorded by Ameren, Ameren Missouri, and Ameren Illinois using settlement information provided by MISO. Ameren Missouri records these purchase and sale transactions on a net hourly position. Ameren Missouri records net purchases in a single hour in “Operating Expenses – Purchased power” and net sales in a single hour in “Operating Revenues – Electric” in its statement of income. Ameren Illinois records net purchases in “Operating Expenses – Purchased power” in its statement of income to reflect all of its MISO transactions relating to the procurement of power for its customers. On occasion, Ameren Missouri's and Ameren Illinois' prior-period transactions will be resettled outside the routine settlement process because of a change in MISO’s tariff or a material interpretation thereof. In these cases, Ameren Missouri and Ameren Illinois recognize expenses associated with resettlements once the resettlement is probable and the resettlement amount can be estimated and recognize revenues once the resettlement amount is received.

Nuclear Fuel

Ameren Missouri’s cost of nuclear fuel is capitalized and then amortized to fuel expense on a unit-of-production basis. The cost is charged to "Operating Expenses – Fuel" in the statement of income.

Stock-based Compensation

Stock-based compensation cost is measured at the grant date based on the fair value of the award, net of an assumed forfeiture rate. Ameren recognizes as compensation expense the estimated fair value of stock-based compensation on a straight-line basis over the requisite service period. See Note 12 – Stock-based Compensation for additional information.

Excise Taxes

Ameren Missouri and Ameren Illinois collect from their customers certain excise taxes that are levied on the sale or distribution of natural gas and electricity. Excise taxes are levied on Ameren Missouri's electric and natural gas businesses and on Ameren Illinois' natural gas business. They are recorded gross in “Operating Revenues – Electric,” “Operating Revenues – Gas,” and “Operating Expenses – Taxes other than income taxes” on the statement of income or the statement of income and comprehensive income. Excise taxes for electric service in Illinois are levied on customers and are therefore not included in Ameren Illinois' revenues and expenses. The following table presents the excise taxes recorded in “Operating Revenues – Electric,” “Operating Revenues – Gas,” and “Operating Expenses – Taxes other than income taxes” for the years ended December 31, 2015, 2014, and 2013:

	2015				2014				2013
Ameren Missouri	$	156			$	151			$	152
Ameren Illinois	57				64				61
Ameren	$	213			$	215			$	213

Unamortized Debt Discounts, Premiums, and Issuance Costs

Long-term debt discounts, premiums, and issuance costs are amortized over the lives of the related issuances. Credit facility fees are amortized over the credit facility term.

Income Taxes

Ameren uses an asset and liability approach for its financial accounting and reporting of income taxes, in accordance with authoritative accounting guidance. Deferred tax assets and liabilities are recognized for transactions that are treated differently for financial reporting and income tax return purposes. These deferred tax assets and liabilities are based on statutory tax rates.

We recognize that regulators will probably reduce future revenues for deferred tax liabilities that were initially recorded at rates in excess of the current statutory rate. Therefore, reductions in deferred tax liabilities that were recorded because of decreases in the statutory rate have been credited to a regulatory liability. A regulatory asset has been established to recognize the probable recovery through future customer rates of tax benefits related to the equity component of allowance for funds used during construction, as well as the effects of tax rate changes.

Investment tax credits used on tax returns for prior years have been deferred as a noncurrent liability. The credits are being amortized over the useful lives of the related investment. Deferred income taxes were recorded on the temporary difference represented by the deferred investment tax credits and a corresponding regulatory liability. This recognizes the expected reduction in rates for future lower income taxes associated with the amortization of the investment tax credits. See Note 13 – Income Taxes.

Ameren Missouri, Ameren Illinois, and all the other Ameren subsidiary companies are parties to a tax allocation agreement with Ameren (parent) that provides for the allocation of consolidated tax liabilities. The tax allocation agreement specifies that each party be allocated an amount of tax similar to that which would be owed or refunded had the party been separately subject to tax. Any net benefit attributable to the parent is reallocated to the other parties. This reallocation is treated as a capital contribution to the party receiving the benefit.

Earnings per Share

Basic earnings per share is computed by dividing net income attributable to Ameren common shareholders by the weighted-average number of common shares outstanding during the period. Earnings per diluted share is computed by dividing net income attributable to Ameren common shareholders by the weighted-average number of diluted common shares outstanding during the period. Earnings per diluted share reflects the potential

dilution that would occur if certain stock-based performance share units were settled. The number of performance share units assumed to be settled was 1.0 million, 1.8 million, and 1.9 million for the years ended December 31, 2015, 2014, and 2013, respectively. There were no potentially dilutive securities excluded from the diluted earnings per share calculations for the years ended December 31, 2015, 2014, and 2013.

Capital Contributions and Return of Capital

In 2015, Ameren Missouri and Ameren Illinois received cash capital contributions of $224 million and $25 million, respectively, from Ameren (parent) as a result of the tax allocation agreement. Additionally, as of December 31, 2015, Ameren Missouri accrued a $38 million capital contribution related to the same agreement.

In 2014, Ameren Missouri and Ameren Illinois received cash capital contributions of $215 million and $15 million, respectively, from Ameren (parent) as a result of the tax allocation agreement. Additionally, as of December 31, 2014, Ameren Missouri accrued a $9 million capital contribution related to the same agreement. Also in 2014, Ameren Missouri returned capital of $215 million to Ameren (parent).

Supplemental Cash Flow Information

The following table presents additional information regarding Ameren's consolidated statement of cash flows for the years ended December 31, 2015, 2014, and 2013:

	2015				2014				2013
Cash paid (refunded) during the year:
Interest
Continuing operations(a)	$	335			$	333			$	362
Discontinued operations(b)	—				—				31
	$	335			$	333			$	393
Income taxes, net
Continuing Operations	$	(17	)		$	(41	)		$	116
Discontinued Operations	2				14				(108		)
	$	(15	)		$	(27	)		$	8

(a)	Net of $17 million, $18 million, and $20 million capitalized, respectively.

(b)	Net of $- million, $- million, and $17 million capitalized, respectively.

See Note 3 – Property and Plant, Net, for information on accrued capital expenditures.

Accounting Changes and Other Matters

The following is a summary of recently adopted authoritative accounting guidance, as well as guidance issued but not yet adopted, that could affect the Ameren Companies.

Revenue from Contracts with Customers

In May 2014, the FASB issued authoritative accounting guidance that changes the criteria for recognizing revenue from a contract with a customer. The underlying principle of the guidance is that an entity will recognize revenue for the transfer of promised goods or services to customers at an amount that

the entity expects to be entitled to in exchange for those goods or services. The guidance also requires additional disclosures to enable users of financial statements to understand the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers. Entities can apply the guidance retrospectively to each reporting period presented or retrospectively by recording a cumulative effect adjustment to retained earnings in the period of initial adoption. The Ameren Companies are currently assessing the impacts of this guidance on their results of operations, financial position, and disclosures, including their accounting for contributions in aid of construction and similar arrangements, as well as the transition method that they will use to adopt the guidance. In August 2015, the FASB deferred the effective date of this revenue guidance to the first quarter of 2018, with an option for entities to early adopt in the first quarter of 2017. The Ameren Companies do not expect to early adopt this guidance.

Amendments to the Consolidation Analysis

In February 2015, the FASB issued authoritative accounting guidance that amends the consolidation analysis for variable interest entities and voting interest entities. The new guidance affects (1) limited partnerships and similar legal entities, (2) evaluating fees paid to a decision maker or service provider as a variable interest, (3) the effect of fee arrangements on the primary beneficiary determination, (4) the effect of related parties on the primary beneficiary determination, and (5) certain investment funds. The guidance is effective for the Ameren Companies in the first quarter of 2016, and can be applied retrospectively to each reporting period presented or retrospectively by recording a cumulative effect adjustment to retained earnings in the period of initial adoption. The Ameren Companies are currently assessing this guidance and do not expect any material impacts to their results of operations, financial position or cash flows.

Presentation of Debt Issuance Costs

In April 2015, the FASB issued authoritative accounting guidance to simplify the presentation of debt issuance costs in the balance sheet. The guidance requires debt issuance costs to be presented as a reduction to the associated debt liability. Previously, debt issuance costs were presented in "Other assets" on the Ameren Companies' balance sheets. The Ameren Companies early adopted this standard in 2015 and applied the guidance retrospectively. At December 31, 2015, debt issuance costs of $43 million, $19 million, and $18 million were presented in "Long-term debt, net" on Ameren's, Ameren Missouri's, and Ameren Illinois' balance sheets, respectively. At December 31, 2014, debt issuance costs of $35 million, $18 million, and $17 million previously presented in "Other assets" on Ameren's, Ameren Missouri's, and Ameren Illinois' respective balance sheets were reclassified to Long-term debt, net" for comparative purposes. See Note 5 – Long-Term Debt and Equity Financings for additional information. The implementation of this authoritative accounting guidance did not affect the Ameren Companies' results of operations or cash flows.

Balance Sheet Classification of Deferred Income Taxes

In November 2015, the FASB issued authoritative accounting guidance to simplify the presentation of deferred income taxes in the balance sheet. The guidance requires all deferred tax assets and liabilities, along with any related valuation allowances, to be classified as noncurrent on the balance sheet. Previously, the current portion of deferred taxes was presented as "Current accumulated deferred income taxes, net" and the noncurrent portion of deferred taxes was presented as "Accumulated deferred income taxes, net" on the Ameren Companies' balance sheets. The Ameren Companies early adopted this standard in 2015 and applied the guidance retrospectively. At December 31, 2014, the current deferred income taxes of $352 million, $49 million, and $160 million, which were previously presented as "Current accumulated deferred income taxes, net" on Ameren's, Ameren Missouri's, and Ameren Illinois' respective balance sheets, were reclassified and presented in "Accumulated deferred income taxes, net" for comparative purposes. The implementation of this authoritative accounting guidance did not affect the Ameren Companies' results of operations or cash flows.

Leases

In February 2016, the FASB issued authoritative accounting guidance that will require an entity to recognize assets and liabilities arising from a lease. Consistent with current GAAP, the recognition, measurement, and presentation of expenses and cash flows arising from a lease will depend primarily on its classification as a finance or operating lease. The guidance also requires additional disclosures to enable users of financial statements to understand the amount, timing, and uncertainty of cash flows arising from leases. The guidance will be effective for the Ameren Companies in the first quarter of 2019, and includes an option for entities to early adopt. The guidance requires a retrospective cumulative adjustment to retained earnings in the period of initial adoption. The Ameren Companies are currently assessing the impacts of this guidance on their results of operations, financial position, cash flows and disclosures.

NOTE 2 – RATE AND REGULATORY MATTERS

Below is a summary of significant regulatory proceedings and related lawsuits. We are unable to predict the ultimate outcome of these matters, the timing of the final decisions of the various agencies and courts, or the effect on our results of operations, financial position, or liquidity.

Missouri

2015 Electric Rate Order

In April 2015, the MoPSC issued an order approving a $122 million increase in Ameren Missouri’s annual revenues for electric service, including $109 million related to the increase in net energy costs above those included in base rates previously authorized by the MoPSC. The revenue increase was based on a 9.53% return on common equity, a capital structure composed of 51.8% common equity, and a rate base of $7.0 billion to reflect

investments through December 31, 2014. Rate changes consistent with the order became effective on May 30, 2015.

The order approved Ameren Missouri’s request for continued use of the FAC; however, it changed the FAC to exclude all transmission revenues and substantially all transmission charges. The order did not approve the continued use of the regulatory tracking mechanisms for storm costs or for vegetation management and infrastructure inspection costs. These changes to Ameren Missouri’s recovery mechanisms are expected to contribute to regulatory lag. The order did approve the continued use of the regulatory tracking mechanisms for pension and other postretirement benefits, renewable energy standard costs, solar rebates, and uncertain tax positions that the MoPSC authorized in prior electric rate orders.

In addition, the order approved a reduction to Noranda’s electric rates with an offsetting increase in electric rates for Ameren Missouri’s other customers. The rate shift is designed to be revenue neutral for Ameren Missouri. In June 2015, Ameren Missouri filed an appeal with the Missouri Court of Appeals, Western District, concerning the reduction to Noranda’s electric rates included in the MoPSC’s order. In February 2016, Ameren Missouri withdrew its appeal.

MEEIA

The MEEIA established a regulatory framework that, among other things, requires the MoPSC to ensure that a utility’s financial incentives are aligned to help customers use energy more efficiently, to provide timely cost recovery, and to provide earnings opportunities associated with cost-effective energy efficiency programs. Missouri does not have a law mandating energy efficiency programs.

In August 2012, the MoPSC approved Ameren Missouri’s customer energy efficiency programs, net shared benefits, and performance incentive for 2013 through 2015. From 2013 through 2015, Ameren Missouri invested $134 million in customer energy efficiency programs and realized $174 million of net shared benefits. The MoPSC also established a performance incentive that would provide Ameren Missouri an opportunity to earn additional revenues by achieving certain customer energy efficiency goals, including $19 million if 100% of the goals were achieved during the three-year period, with the potential to earn a larger performance incentive if Ameren Missouri’s energy savings exceeded those goals.

In June 2015, the MoPSC staff filed a complaint case with the MoPSC regarding the method and inputs used in calculating the performance incentive for 2014 and 2015. In November 2015, the MoPSC issued an order that adopted the MoPSC staff’s method and inputs used in calculating the performance incentive for 2014 and 2015. Ameren Missouri filed an appeal of the order with the Missouri Court of Appeals, Western District. If the Missouri Court of Appeals upholds the MoPSC order, the performance incentive awarded from the 2014 and 2015 MEEIA programs will be significantly less than the performance incentive calculated using Ameren Missouri’s interpretation. Ameren Missouri has not recorded revenues associated with the

performance incentive for any of the MEEIA program years. Ameren Missouri believes that it will ultimately be found to have exceeded 100% of the customer energy efficiency goals, and it therefore expects to recognize revenues of at least $19 million in 2016.

In February 2016, the MoPSC issued an order approving Ameren Missouri's March 2016 to February 2019 MEEIA plan which included a portfolio of customer energy efficiency programs along with a rider to collect the program costs, the throughput disincentive, and a performance incentive from customers. The throughput disincentive recovery will replace the net shared benefits that were collected under the 2013 through 2015 MEEIA plan. The MEEIA rider will allow Ameren Missouri to collect the throughput disincentive without a traditional rate proceeding, until such time as lower volumes resulting from the MEEIA programs are reflected in base rates. Customer rates will be based upon both forecasted program costs and throughput disincentive which will be annually reconciled to actual results. Beginning in March 2016, Ameren Missouri intends to invest $158 million over the three-year period in customer energy efficiency programs. In addition, similar to the MEEIA plan that ended in December 2015, the MoPSC's order approved a performance incentive that would provide Ameren Missouri an opportunity to earn additional revenues by achieving certain customer energy efficiency goals, including $27 million if 100% of the goals are achieved during the three-year period, with the potential to earn more if Ameren Missouri's energy savings exceed those goals. Ameren Missouri must achieve at least 25% of its energy efficiency goals before it earns a performance incentive.

Noranda

Ameren Missouri supplies electricity to Noranda’s aluminum smelter located in southeast Missouri under a long-term power supply agreement. In May 2015, Ameren Missouri notified Noranda of its intent to terminate the agreement effective June 1, 2020. If Ameren Missouri wants to cease providing electricity to Noranda following the termination date, Ameren Missouri would also be required to obtain approval from the MoPSC.

On January 8, 2016, Noranda announced that production had been idled at two of its three pot lines at the smelter following an electric supply circuit failure on assets not owned by Ameren Missouri. On January 13, 2016, Noranda announced that the smelter’s “remaining operations will be curtailed on or before March 12, 2016, unless [Noranda] is able to secure a substantially more sustainable power rate for the smelter and materially improve [Noranda’s] overall liquidity.” Ameren Missouri has been working with Noranda, legislators and other stakeholders on a potential legislative solution to support Noranda’s operations.

In its April 2015 electric rate order, the MoPSC approved a rate design that established $78 million in annual revenues, net of fuel and purchased power costs, as Noranda’s portion of Ameren Missouri’s revenue requirement. The portion of Ameren Missouri’s annual revenue requirement reflected in Noranda’s electric rate is based on the smelter using approximately 4.2

million megawatthours annually, which is almost 100% of its operating capacity. Ameren Missouri’s rates, including those for Noranda, are seasonal. Noranda’s summer base rate (June through September) is $45.78 per megawatthour and its winter base rate (October through May) is $31.11 per megawatthour.

In 2016, actual sales volumes to Noranda will be significantly below the sales volumes reflected in rates. As a result, Ameren Missouri will not fully recover its revenue requirement until rates are adjusted by the MoPSC in a future electric rate case to accurately reflect Noranda’s actual sales volumes. In light of the Noranda announcements described above, Ameren Missouri expects to employ a provision in its FAC tariff that, under certain circumstances, allows Ameren Missouri to retain a portion of the revenues from any off-system sales it makes as a result of reduced tariff sales to Noranda. The current market price of electricity is less than Noranda’s electric rate, and Ameren Missouri expects market prices to remain below Noranda’s electric rate during 2016. Accordingly, this FAC provision would not enable Ameren Missouri to fully recover its revenue requirement under current market conditions.

Although Ameren Missouri has not decided when to file its next electric rate case, on January 11, 2016, Ameren Missouri filed a notice with the MoPSC, that would enable Ameren Missouri to file a rate case after 60 days. Ameren Missouri expects to file a rate case in 2016 and expects the resulting new rates to reflect Noranda’s actual sales volumes which would prospectively eliminate the impact of the current revenue shortfall. The rate case would take place over a period of up to 11 months from the date of filing. Ameren Missouri may seek recovery of lost revenues in a filing with the MoPSC for certain costs incurred but not contemporaneously recovered as a result of Noranda's reduced operations. Ameren Missouri will continue to monitor Noranda’s sales volumes and to evaluate regulatory and legislative options that might mitigate adverse financial impacts. The reduction in Noranda’s sales volumes will adversely affect Ameren’s and Ameren Missouri’s results of operations, financial condition, and liquidity until customer rates are adjusted in a future rate case.

On February 8, 2016, Noranda filed voluntary petitions for a court-supervised restructuring process under Chapter 11 of the United States Bankruptcy Code. In the filing, Noranda reaffirmed that the remaining pot line will continue to operate at the smelter until March 2016, at which time operation of the line will be curtailed. Noranda stated it would maintain the flexibility to restart operations at the smelter should conditions allow. For utility service through February 8, 2016, Noranda had prepaid an amount to Ameren Missouri in excess of its utility service usage. Ameren Missouri expects to be paid in full for utility services provided after February 8, 2016.

ATXI Transmission Projects

In May 2015, the MoPSC granted ATXI a certificate of convenience and necessity for the seven-mile portion of the Illinois Rivers project located in Missouri.

In June 2015, ATXI made a filing with the MoPSC requesting a certificate of convenience and necessity for the Mark Twain project. The Mark Twain project is a MISO-approved 100-mile transmission line located in northeast Missouri. A decision is expected from the MoPSC in 2016.

Illinois

IEIMA

Under the provisions of the IEIMA's performance-based formula rate-making framework, which currently extends through 2019, Ameren Illinois’ electric delivery service rates are subject to an annual revenue requirement reconciliation to its actual recoverable costs. Throughout each year, Ameren Illinois records a regulatory asset or a regulatory liability and a corresponding increase or decrease to operating revenues for any differences between the revenue requirement reflected in customer rates for that year and its estimate of the probable increase or decrease in the revenue requirement expected to ultimately be approved by the ICC based on that year's actual recoverable costs incurred. As of December 31, 2015, Ameren Illinois had recorded regulatory assets of $62 million and $103 million, including interest, to reflect its expected 2015 and the 2014 approved revenue requirement reconciliation adjustments, respectively. As of December 31, 2014, Ameren Illinois had recorded a $65 million regulatory asset to reflect its approved 2013 revenue requirement reconciliation adjustment, which was collected, with interest, from customers during 2015.

In December 2015, the ICC issued an order in Ameren Illinois’ annual update filing approving a $106 million increase in Ameren Illinois’ electric delivery service revenue requirement beginning in January 2016. This update reflects an increase to the annual formula rate based on 2014 actual recoverable costs and expected net plant additions for 2015, an increase to include the 2014 revenue requirement reconciliation adjustment, which was recorded as a regulatory asset at December 31, 2015, and a decrease for the conclusion of the 2013 revenue requirement reconciliation adjustment, which was fully collected from customers in 2015.

In December 2013, the ICC issued an order that disallowed, in part, the recovery from customers of the debt premium costs paid by Ameren Illinois for a tender offer in August 2012 to repurchase outstanding senior secured notes. As a result of the ICC order, in 2013, Ameren and Ameren Illinois each recorded a pretax charge to earnings of $15 million relating to the partial disallowance of the debt premium costs. In December 2014, the ICC issued an order that allowed partial recovery from customers of the previously disallowed debt premium costs. Accordingly, in 2014, Ameren and Ameren Illinois each recorded a pretax increase to earnings of $11 million to reflect the partial recovery

of the debt premium costs. Ameren and Ameren Illinois recorded the effects of the 2013 and 2014 orders to "Interest charges" with a corresponding offset to "Regulatory assets."

2015 Natural Gas Delivery Service Rate Order

In December 2015, the ICC issued a rate order that approved an increase in revenues for Ameren Illinois' natural gas delivery service of $45 million. The revenue increase was based on a 9.6% return on common equity, a capital structure composed of 50% common equity, and a rate base of $1.2 billion. The rate order was based on a 2016 future test year. The rate changes were in effect in January 2016. In addition, the rate order approved the VBA for residential and small nonresidential customers beginning in 2016.

2015 ICC Purchased Power Reconciliation

In January 2015, the ICC issued an order that approved Ameren Illinois' reconciliation of revenues collected under its purchased power rider mechanism and Ameren Illinois' related cumulative power usage cost. In the first quarter of 2015, based on the January 2015 order, both Ameren and Ameren Illinois recorded a $15 million increase to electric revenues for the recovery of this cumulative power usage cost from electric customers.

ATXI Transmission Project

The Spoon River project is a MISO-approved 46-mile transmission line to be constructed in northwest Illinois. In September 2015, the ICC granted a certificate of public convenience and necessity and project approval for the Spoon River project.

Federal

Ameren Illinois Electric Transmission Rate Refund

In July 2012, the FERC issued an order concluding that Ameren Illinois improperly included acquisition premiums, including goodwill, in determining the common equity used in its electric transmission formula rate and thereby inappropriately recovered a higher amount from its electric transmission customers. The order required Ameren Illinois to make refunds to customers for such improperly included amounts.

In July 2015, the FERC approved a settlement agreement between Ameren Illinois and the affected customers. The settlement agreement required Ameren Illinois to make refunds and payments of $8 million to electric transmission customers, all of which was paid in 2015. The settlement agreement also required Ameren Illinois to take other actions, such as reducing common equity for electric transmission ratemaking purposes on a prospective basis. The transmission rates that became effective on January 1, 2016, reflect these adjustments.

FERC Complaint Cases

In November 2013, a customer group filed a complaint case

with the FERC seeking a reduction in the allowed base return on common equity for the FERC-regulated transmission rate base under the MISO tariff from 12.38% to 9.15%. In December 2015, an administrative law judge issued an initial decision in the November 2013 complaint case that would lower the allowed base return on common equity to 10.32% and would require customer refunds to be issued for the 15-month period ending February 2015. The allowed base return on common equity in the initial decision was based on multiple inputs, including observable market data for the six months ended June 30, 2015. The FERC is expected to issue a final order on the November 2013 complaint case by October 2016.

As the maximum FERC-allowed refund period for the November 2013 complaint case ended in February 2015, another customer complaint case was filed in February 2015. The February 2015 complaint case seeks a reduction in the allowed base return on common equity for the FERC-regulated transmission rate base under the MISO tariff to 8.67%. The initial decision from an administrative law judge in the February 2015 complaint case, which will subsequently require FERC approval, is expected to be issued by June 2016.

On January 6, 2015, a FERC-approved incentive adder of up to 50 basis points on the allowed base return on common equity for our participation in an RTO became effective. Beginning with its January 6, 2015 effective date, the incentive adder will reduce any refund to customers relating to a reduction of the allowed base return on common equity from the complaint cases discussed above.

As of December 31, 2015, Ameren and Ameren Illinois had current regulatory liabilities of $45 million and $32 million, respectively, representing their estimates of the potential refunds

from the November 12, 2013 refund effective date through December 31, 2015. Ameren and Ameren Illinois recorded liabilities to reflect the allowed base return on common equity in the initial decision for the November 2013 complaint case refund period, and the observable market data for the six months ended December 31, 2015, for the February 2015 complaint case refund period. Ameren’s and Ameren Illinois’ liabilities also reflect the January 6, 2015 incentive adder discussed above. Ameren Missouri did not record a liability as of December 31, 2015, and it does not expect that a reduction in the FERC-allowed base return on common equity for MISO transmission owners would be material to its results of operations, financial position, or liquidity.

Combined Construction and Operating License

In 2008, Ameren Missouri filed an application with the NRC for a COL for a second nuclear unit at Ameren Missouri's existing Callaway County, Missouri, energy center site. In 2009, Ameren Missouri suspended its efforts to build a second nuclear unit at its existing Callaway site, and the NRC suspended review of the COL application. Prior to suspending its efforts, Ameren Missouri had capitalized $69 million related to the project. Primarily because of changes in vendor support for licensing efforts at the NRC, Ameren Missouri’s assessment of long-term capacity needs, declining costs of alternative generation technologies, and the regulatory framework in Missouri, Ameren Missouri discontinued its efforts to license and build a second nuclear unit at its existing Callaway site. As a result of this decision, in the second quarter of 2015, Ameren and Ameren Missouri recognized a $69 million noncash pretax provision for all of the previously capitalized COL costs. Ameren Missouri has withdrawn its COL application with the NRC.

Regulatory Assets and Liabilities

In accordance with authoritative accounting guidance regarding accounting for the effects of certain types of regulation, we defer certain costs as regulatory assets pursuant to actions of regulators or because we expect to recover such costs in rates charged to customers. We may also defer certain amounts as regulatory liabilities because of actions of regulators or because we expect that such amounts will be returned to customers in future rates. The following table presents our regulatory assets and regulatory liabilities at December 31, 2015 and 2014:

		2015												2014
		Ameren Missouri				Ameren Illinois				Ameren					Ameren Missouri				Ameren Illinois				Ameren
Current regulatory assets:
Under-recovered FAC(a)(b)		$	37			$	—			$	37				$	128			$	—			$	128
Under-recovered Illinois electric power costs(c)		—				3				3					—				2				2
Under-recovered PGA(c)		—				8				8					—				20				20
MTM derivative losses(d)		29				45				74					32				42				74
Energy efficiency riders(e)		23				—				23					3				—				3
IEIMA revenue requirement reconciliation adjustment(a)(f)		—				103				103					—				65				65
FERC revenue requirement reconciliation adjustment(a)(g)		—				8				12					—				—				3
Total current regulatory assets		$	89			$	167			$	260				$	163			$	129			$	295
Noncurrent regulatory assets:
Pension and postretirement benefit costs(h)		$	95			$	202			$	297				$	148			$	275			$	423
Income taxes(i)		254				4				258					253				3				256
Asset retirement obligations(j)		—				4				4					—				5				5
Callaway costs(a)(k)		32				—				32					36				—				36
Unamortized loss on reacquired debt(a)(l)		69				69				138					72				80				152
Contaminated facilities costs(m)		—				230				230					—				251				251
MTM derivative losses(d)		15				175				190					14				144				158
Storm costs(a)(n)		—				9				9					—				3				3
Demand-side costs before the MEEIA implementation(a)(o)		31				—				31					44				—				44
Workers’ compensation claims(p)		6				7				13					7				7				14
Credit facilities fees(q)		4				—				4					5				—				5
Construction accounting for pollution control equipment(a)(r)		20				—				20					21				—				21
Solar rebate program(a)(s)		74				—				74					88				—				88
IEIMA revenue requirement reconciliation adjustment(a)(f)		—				62				62					—				101				101
FERC revenue requirement reconciliation adjustment(a)(g)		—				5				11					—				8				12
Other		5				4				9					7				6				13
Total noncurrent regulatory assets		$	605			$	771			$	1,382				$	695			$	883			$	1,582
Current regulatory liabilities:
Over-recovered FAC(b)		$	9			$	—			$	9				$	—			$	—			$	—
Over-recovered Illinois electric power costs(c)		—				6				6					—				26				26
Over-recovered PGA(c)		3				—				3					2				25				27
MTM derivative gains(d)		16				1				17					16				1				17
FERC revenue requirement reconciliation adjustment(g)		—				—				—					—				11				11
Estimated refund for FERC complaint cases, orders, and audit findings(t)		—				32				45					—				21				25
Total current regulatory liabilities		$	28			$	39			$	80				$	18			$	84			$	106
Noncurrent regulatory liabilities:
Income taxes(u)		$	36			$	6			$	42				$	41			$	14			$	55
Uncertain tax positions tracker(v)		6				—				6					7				—				7
Removal costs(w)		933				671				1,605					886				643				1,529
Asset retirement obligation(j)		167				—				167					182				—				182
Bad debt riders(x)		—				6				6					—				7				7
Pension and postretirement benefit costs tracker(y)		19				—				19					24				—				24
Energy efficiency riders(e)		—				36				36					—				39				39
Renewable energy credits(z)		—				12				12					1				—				1
Storm tracker(aa)		9				—				9					6				—				6
Other		2				1				3					—				—				—
Total noncurrent regulatory liabilities		$	1,172			$	732			$	1,905				$	1,147			$	703			$	1,850

(a)	These assets earn a return.

(b)	Under-recovered or over-recovered fuel costs to be recovered or refunded through the FAC. Specific accumulation periods aggregate the under-recovered or over-recovered costs over four months, any related adjustments that occur over the following four months, and the recovery from or refund to customers that occurs over the next eight months.

(c)	Under-recovered or over-recovered costs from utility customers. Amounts will be recovered from, or refunded to, customers within one year of the deferral.

(d)	Deferral of commodity-related derivative MTM losses or gains. See Note 7 – Derivative Financial Instruments for additional information.

(e)

The Ameren Missouri balance relates to the MEEIA. Beginning in January 2014, the MEEIA rider allowed Ameren Missouri to collect from or refund to customers any annual difference in the actual amounts incurred and the amounts collected from customers for the MEEIA program costs and its net shared benefits. Under the MEEIA rider, collections from or refunds to customers occur one year after the program costs and lost revenues are incurred. The Ameren Illinois balance relates to a regulatory tracking mechanism to recover its electric and natural gas costs associated with developing, implementing, and evaluating customer energy efficiency and demand response programs. Any under-recovery or over-recovery will be collected from or refunded to customers over the 12 months following the plan year.

(f)	The difference between Ameren Illinois' annual revenue requirement calculated under the IEIMA's performance-based formula ratemaking framework and the revenue requirement included in customer rates for that year. Subject to ICC approval, these amounts will be collected from or refunded to customers with interest within two years.

(g)	Ameren Illinois' and ATXI's annual revenue requirement reconciliation adjustments calculated pursuant to the FERC's electric transmission formula ratemaking framework. The under-recovery or over-recovery will be recovered from or refunded to customers within two years.

(h)	These costs are being amortized in proportion to the recognition of prior service costs (credits) and actuarial losses (gains) attributable to Ameren’s pension plan and postretirement benefit plans. See Note 11 – Retirement Benefits for additional information.

(i)	Tax benefits related to the equity component of allowance for funds used during construction, as well as the effects of tax rate changes. This will be recovered over the expected life of the related assets.

(j)	Recoverable or refundable removal costs for AROs, including net realized and unrealized gains and losses related to the nuclear decommissioning trust fund investments. See Note 1 – Summary of Significant Accounting Policies – Asset Retirement Obligations and Investments.

(k)	Ameren Missouri’s Callaway energy center operations and maintenance expenses, property taxes, and carrying costs incurred between the plant in-service date and the date the plant was reflected in rates. These costs are being amortized over the remaining life of the energy center's original operating license through 2024.

(l)	Losses related to reacquired debt. These amounts are being amortized over the lives of the related new debt issuances or the original lives of the old debt issuances if no new debt was issued.

(m)	The recoverable portion of accrued environmental site liabilities that will be collected from electric and natural gas customers through ICC-approved cost recovery riders. The period of recovery will depend on the timing of remediation expenditures. See Note 15 – Commitments and Contingencies for additional information.

(n)	Storm costs from 2013 and 2015 deferred in accordance with the IEIMA. These costs are being amortized over five-year periods beginning in 2013 and 2015, respectively.

(o)

Demand-side costs incurred prior to implementation of the MEEIA in 2013, including the costs of developing, implementing, and evaluating customer energy efficiency and demand response programs. Costs incurred from May 2008 through September 2008 are being amortized over a 10-year period that began in March 2009. Costs incurred from October 2008 through December 2009 are being amortized until May 2017. Costs incurred from January 2010 through February 2011 are being amortized over a six-year period that began in August 2011. Costs incurred from March 2011 through July 2012 are being amortized over a six-year period that began in January 2013. Costs incurred from August 2012 through December 2012 are being amortized over a six-year period that began in June 2015.

(p)	The period of recovery will depend on the timing of actual expenditures.

(q)	Ameren Missouri’s costs incurred to enter into and maintain the Missouri Credit Agreement. Additional costs were incurred in December 2014 to amend and restate the Missouri Credit Agreement. These costs are being amortized over the life of the credit facility, ending in December 2019, to construction work in progress, which will be depreciated when assets are placed into service.

(r)	The MoPSC’s May 2010 electric rate order allowed Ameren Missouri to record an allowance for funds used during construction for pollution control equipment at its Sioux energy center until the cost of that equipment was included in customer rates beginning in 2011. These costs are being amortized over the expected life of the Sioux energy center, which is currently through 2033.

(s)	Costs associated with Ameren Missouri's solar rebate program beginning in August 2012 to fulfill its renewable energy portfolio requirement. These costs are being amortized over three years, beginning in June 2015.

(t)	Estimated refunds to transmission customers related to FERC orders. See Ameren Illinois Electric Transmission Rate Refund and FERC Complaint Cases above.

(u)	Unamortized portion of investment tax credits and reductions to deferred tax liabilities recorded at rates in excess of current statutory rates. The unamortized portion of investment tax credits and the reduction to deferred tax liabilities are being amortized over the expected life of the underlying assets.

(v)	The tracker is amortized over three years, beginning from the date the amounts are included in rates. See Note 13 – Income Taxes for additional information.

(w)	Estimated funds collected for the eventual dismantling and removal of plant from service, net of salvage value, upon retirement related to our rate-regulated operations.

(x)

A regulatory tracking mechanism for the difference between the level of bad debt incurred by Ameren Illinois under GAAP and the level of such costs included in electric and natural gas rates. The over-recovery relating to 2013 was refunded to customers from June 2014 through May 2015. The over-recovery relating to 2014 will be refunded to customers from June 2015 through May 2016. The over-recovery relating to 2015 will be refunded to customers from June 2016 through May 2017.

(y)

A regulatory tracking mechanism for the difference between the level of pension and postretirement benefit costs incurred by Ameren Missouri under GAAP and the level of such costs included in rates. For periods prior to December 2014, the MoPSC's April 2015 electric rate order directed the amortization to occur over three to five years, beginning in June 2015. For periods after December 2014, the amortization period will be determined in a future electric rate case.

(z)

The Ameren Missouri balance includes the costs of renewable energy credits to fulfill Ameren Missouri's renewable energy portfolio requirement from August 2012 through December 2013, which were less than the amount included in rates. These costs are being amortized over three years beginning in June 2015. The Ameren Illinois balance includes funds collected from customers for the purchase of renewable energy credits through IPA procurements for distributed generation. The balance will be amortized as renewable energy credits are purchased.

(aa)

A regulatory tracking mechanism at Ameren Missouri for the difference between the level of storm costs incurred in a particular year and the level of such costs included in rates. For periods prior to December 2014, the MoPSC's April 2015 electric rate order directed the amortization to occur over five years, beginning in June 2015. For periods after December 2014, the amortization period will be determined in a future electric rate case. The April 2015 MoPSC order did not approve the continued use of the regulatory tracking mechanisms for storm costs.

Ameren, Ameren Missouri, and Ameren Illinois continually assess the recoverability of their regulatory assets. Under current accounting standards, regulatory assets are charged to earnings when it is no longer probable that such amounts will be recovered through future revenues. To the extent that payments of regulatory liabilities are no longer probable, the amounts are credited to earnings.

NOTE 3 – PROPERTY AND PLANT, NET

The following table presents property and plant, net, for each of the Ameren Companies at December 31, 2015 and 2014:

		Ameren Missouri(a)				Ameren Illinois				Other				Ameren(a)
2015
Property and plant, at original cost:
Electric		$	17,521			$	7,253			$	387			$	25,161
Natural gas		445				1,997				—				2,442
		17,966				9,250				387				27,603
Less: Accumulated depreciation and amortization		7,460				2,632				255				10,347
		10,506				6,618				132				17,256
Construction work in progress:
Nuclear fuel in process		275				—				—				275
Other		402				230				636				1,268
Property and plant, net		$	11,183			$	6,848			$	768			$	18,799
2014
Property and plant, at original cost:
Electric		$	17,052			$	6,517			$	344			$	23,913
Natural gas		431				1,854				—				2,285
		17,483				8,371				344				26,198
Less: Accumulated depreciation and amortization		7,086				2,422				251				9,759
		10,397				5,949				93				16,439
Construction work in progress:
Nuclear fuel in process		209				—				—				209
Other		261				216				299				776
Property and plant, net		$	10,867			$	6,165			$	392			$	17,424

(a)

Amounts in Ameren and Ameren Missouri include two CTs under separate capital lease agreements. The gross cumulative asset value of those agreements was $233 million at December 31, 2015 and 2014. The total accumulated depreciation associated with the two CTs was $72 million and $66 million at December 31, 2015 and 2014, respectively. In addition, Ameren Missouri has investments in debt securities, which were classified as held-to-maturity and recorded in "Other assets", related to the two CTs from the city of Bowling Green and Audrain County. As of December 31, 2015 and 2014, the carrying value of these debt securities was $288 million and $294 million, respectively.

The following table provides accrued capital and nuclear fuel expenditures at December 31, 2015, 2014, and 2013, which represent noncash investing activity excluded from the accompanying statements of cash flows:

	Ameren(a)				Ameren Missouri				Ameren Illinois
Accrued capital expenditures:
2015	$	235			$	85			$	92
2014	181				72				59
2013	175				74				86
Accrued nuclear fuel expenditures:
2015	16				16				(b)
2014	13				13				(b)
2013	8				8				(b)

(a)	Includes amounts for Ameren registrant and nonregistrant subsidiaries.

(b)	Not applicable.

NOTE 4 – SHORT-TERM DEBT AND LIQUIDITY

The liquidity needs of the Ameren Companies are typically supported through the use of available cash, drawings under committed credit agreements, commercial paper issuances, or in the case of Ameren Missouri and Ameren Illinois, short-term intercompany borrowings.

Credit Agreements

The Credit Agreements provide a total of $2.1 billion of credit through their December 2019 maturity date. The facilities include 24 international, national, and regional lenders, with no single lender providing more than $115 million of credit in aggregate.

The obligations of each borrower under the respective Credit Agreements to which it is a party are several and not joint. Except under limited circumstances relating to expenses and indemnities, the obligations of Ameren Missouri and Ameren Illinois under the respective Credit Agreements are not guaranteed by Ameren or any other subsidiary of Ameren. The following table presents the maximum aggregate amount available to each borrower under each facility which will expire in December 2019 (the amount being each borrower's "Borrowing Sublimit"):

		Missouri Credit Agreement			Illinois Credit Agreement
Ameren		$	700		$	500
Ameren Missouri		800			(a)
Ameren Illinois		(a)			800

(a)	Not applicable.

Ameren has the option to seek additional commitments from existing or new lenders to increase the total facility size of the Credit Agreements to a maximum of $1.2 billion for the Missouri Credit Agreement and $1.3 billion for the Illinois Credit Agreement. The principal amount of each revolving loan owed by a borrower under any of the Credit Agreements to which it is a party will be due and payable no later than the maturity date of such Credit Agreement. The principal amount of each revolving loan owed by Ameren Missouri or Ameren Illinois under the applicable Credit Agreement will be due and payable no later than the earlier of the maturity date or 364 days after the date of such loan. The Credit Agreements are currently scheduled to mature in December 2019, but the maturity date may be extended once or twice for additional one-year periods upon mutual consent of the borrowers and lenders.

The obligations of all borrowers under the Credit Agreements are unsecured. Loans are available on a revolving

basis under each of the Credit Agreements. Funds borrowed may be repaid and, subject to satisfaction of the conditions to borrowing, reborrowed from time to time. At the election of each borrower, the interest rates on such loans will be the alternate base rate plus the margin applicable to the particular borrower and/or the eurodollar rate plus the margin applicable to the particular borrower. The applicable margins will be determined by the borrower's long-term unsecured credit ratings or, if no such ratings are in effect, the borrower's corporate/issuer ratings then in effect. The borrowers have received commitments from the lenders to issue letters of credit up to $100 million under each of the Credit Agreements. In addition, the issuance of letters of credit is subject to the $2.1 billion overall combined facility borrowing limitations of the Credit Agreements.

The borrowers will use the proceeds from any borrowings under the Credit Agreements for general corporate purposes, including working capital, commercial paper liquidity support, issuance of letters of credit, loan funding under the Ameren money pool arrangements, and other short-term intercompany loan arrangements, or for paying fees and expenses incurred in connection with the Credit Agreements. Both of the Credit Agreements are available to Ameren to support issuances under Ameren's commercial paper program, subject to borrowing sublimits. The Missouri Credit Agreement and the Illinois Credit Agreement are available to support issuances under Ameren (parent)'s, Ameren Missouri's and Ameren Illinois' commercial paper programs, respectively. As of December 31, 2015, based on commercial paper outstanding and letters of credit issued under the Credit Agreements, the aggregate amount of credit capacity available to Ameren (parent), Ameren Missouri, and Ameren Illinois, collectively, was $1.8 billion.

Ameren, Ameren Missouri, and Ameren Illinois did not borrow under the Credit Agreements for the years ended December 31, 2015 and 2014.

Commercial Paper

The following table summarizes the borrowing activity and relevant interest rates under Ameren (parent)'s, Ameren Missouri's and Ameren Illinois' commercial paper programs, for the years ended December 31, 2015 and 2014:

		Ameren (parent)				Ameren Missouri			Ameren Illinois			Ameren Consolidated
2015
Average daily commercial paper outstanding		$	721			$	42		$	4		$	767
Outstanding borrowings at period-end		301				—			—			301
Weighted-average interest rate		0.57		%		0.50		%	0.44		%	0.55		%
Peak commercial paper during period(a)		$	874			$	294		$	48		$	1,108
Peak interest rate		0.91		%		0.60		%	0.60		%	0.91		%
2014
Average daily commercial paper outstanding		$	423			$	110		$	165		$	639
Outstanding borrowings at period-end		585				97			32			714
Weighted-average interest rate		0.36		%		0.38		%	0.32		%	0.36		%
Peak commercial paper during period(a)		$	625			$	495		$	300		$	910
Peak interest rate		0.75		%		0.70		%	0.60		%	0.75		%

(a)	The timing of peak commercial paper issuances varies by company, and therefore the peak amounts presented by company might not equal the Ameren Consolidated peak commercial paper issuances for the period.

Indebtedness Provisions and Other Covenants

The information below is a summary of the Ameren Companies’ compliance with indebtedness provisions and other covenants.

The Credit Agreements contain conditions for borrowings and issuances of letters of credit. These include the absence of default or unmatured default, material accuracy of representations and warranties (excluding any representation after the closing date as to the absence of material adverse change and material litigation, and the absence of any notice of violation, liability, or requirement under any environmental laws that could have a material adverse effect), and obtainment of required regulatory authorizations. In addition, it is a condition for any Ameren Illinois borrowing that, at the time of and after giving effect to such borrowing, Ameren Illinois not be in violation of any limitation on its ability to incur unsecured indebtedness contained in its articles of incorporation.

The Credit Agreements also contain nonfinancial covenants, including restrictions on the ability to incur liens, to transact with affiliates, to dispose of assets, to make investments in or transfer assets to its affiliates, and to merge with other entities. The Credit Agreements require each of Ameren, Ameren Missouri, and Ameren Illinois to maintain consolidated indebtedness of not more than 65% of its consolidated total capitalization pursuant to a defined calculation set forth in the agreements. As of December 31, 2015, the ratios of consolidated indebtedness to total consolidated capitalization, calculated in accordance with the provisions of the Credit Agreements, were 51%, 49%, and 47%, for Ameren, Ameren Missouri, and Ameren Illinois, respectively. In addition, under the Illinois Credit Agreement and, by virtue of the cross-default provisions of the Missouri Credit Agreement, under the Missouri Credit Agreement, Ameren is required to maintain a ratio of consolidated funds from operations plus interest expense to consolidated interest expense of 2.0 to 1.0. However, the interest coverage requirement applies only at such times as Ameren does not have a senior long-term unsecured credit rating of at least Baa3 from Moody's or BBB- from S&P. As of December 31, 2015, Ameren exceeded the rating requirements; therefore, the interest coverage requirement was not applicable. Any failure by a borrower to satisfy a financial covenant constitutes an immediate default under the applicable Credit Agreement.

The Credit Agreements contain default provisions that apply separately to each borrower; provided, however, that a default of Ameren Missouri or Ameren Illinois under the applicable Credit Agreement is also deemed to constitute a default of Ameren under such agreement. Defaults include a cross-default resulting from a default of such borrower under any other agreement covering outstanding indebtedness of such borrower and certain

subsidiaries (other than project finance subsidiaries and nonmaterial subsidiaries) in excess of $75 million in the aggregate (including under the other Credit Agreement). However, under the default provisions of the Credit Agreements, any default of Ameren under any Credit Agreement that results solely from a default of Ameren Missouri or Ameren Illinois thereunder does not result in a cross-default of Ameren under the other Credit Agreement. Further, the Credit Agreement default provisions provide that an Ameren default under any of the Credit Agreements does not constitute a default by Ameren Missouri or Ameren Illinois.

None of the Ameren Companies' credit agreements or financing agreements contain credit rating triggers that would cause a default or acceleration of repayment of outstanding balances. The Ameren Companies were in compliance with the provisions and covenants of their credit agreements at December 31, 2015.

Money Pools

Ameren has money pool agreements with and among its subsidiaries to coordinate and provide for certain short-term cash and working capital requirements.

Ameren Missouri, Ameren Illinois, and ATXI may participate in the utility money pool as both lenders and borrowers. Ameren and Ameren Services may participate in the utility money pool only as lenders. Surplus internal funds are contributed to the money pool from participants. The primary sources of external funds for the utility money pool are the Credit Agreements and the commercial paper programs. The total amount available to the pool participants from the utility money pool at any given time is reduced by the amount of borrowings made by participants, but it is increased to the extent that the pool participants advance surplus funds to the utility money pool or remit funds from other external sources. The availability of funds is also determined by funding requirement limits established by regulatory authorizations. Participants receiving a loan under the money pool agreement must repay the principal amount of such loan, together with accrued interest. The rate of interest depends on the composition of internal and external funds in the utility money pool. The average interest rate for borrowing under the money pool for the year ended December 31, 2015, was 0.11% (2014 – 0.19%).

See Note 14 – Related Party Transactions for the amount of interest income and expense from the money pool arrangements recorded by the Ameren Companies for the years ended December 31, 2015, 2014, and 2013.

NOTE 5 – LONG-TERM DEBT AND EQUITY FINANCINGS

The following table presents long-term debt outstanding, including maturities due within one year, for the Ameren Companies as of December 31, 2015 and 2014:

	2015				2014
Ameren (Parent):
2.70% Senior unsecured notes due 2020	$	350			$	—
3.65% Senior unsecured notes due 2026	350				—
Total long-term debt, gross	700				—
Less: Unamortized debt issuance costs(a)	(6		)		—
Long-term debt, net	$	694			$	—
Ameren Missouri:
Senior secured notes:(b)
4.75% Senior secured notes due 2015	—				114
5.40% Senior secured notes due 2016	260				260
6.40% Senior secured notes due 2017	425				425
6.00% Senior secured notes due 2018(c)	179				179
5.10% Senior secured notes due 2018	199				199
6.70% Senior secured notes due 2019(c)	329				329
5.10% Senior secured notes due 2019	244				244
5.00% Senior secured notes due 2020	85				85
3.50% Senior secured notes due 2024	350				350
5.50% Senior secured notes due 2034	184				184
5.30% Senior secured notes due 2037	300				300
8.45% Senior secured notes due 2039(c)	350				350
3.90% Senior secured notes due 2042(c)	485				485
3.65% Senior secured notes due 2045	250				—
Environmental improvement and pollution control revenue bonds:
1992 Series due 2022(d)(e)	47				47
1993 5.45% Series due 2028(f)	(f)				(f)
1998 Series A due 2033(d)(e)	60				60
1998 Series B due 2033(d)(e)	50				50
1998 Series C due 2033(d)(e)	50				50
Capital lease obligations:
City of Bowling Green capital lease (Peno Creek CT) due 2022	48				54
Audrain County capital lease (Audrain County CT) due 2023	240				240
Total long-term debt, gross	4,135				4,005
Less: Unamortized discount and premium	(6		)		(6		)
Less: Unamortized debt issuance costs(a)	(19		)		(18		)
Less: Maturities due within one year	(266		)		(120		)
Long-term debt, net	$	3,844			$	3,861

	2015				2014
Ameren Illinois:
Senior secured notes:
6.20% Senior secured notes due 2016(g)	$	54			$	54
6.25% Senior secured notes due 2016(h)	75				75
6.125% Senior secured notes due 2017(h)(i)	250				250
6.25% Senior secured notes due 2018(h)(i)	144				144
9.75% Senior secured notes due 2018(h)(i)	313				313
2.70% Senior secured notes due 2022(h)(i)	400				400
3.25% Senior secured notes due 2025(h)	300				300
6.125% Senior secured notes due 2028(h)	60				60
6.70% Senior secured notes due 2036(h)	61				61
6.70% Senior secured notes due 2036(g)	42				42
4.80% Senior secured notes due 2043(h)	280				280
4.30% Senior secured notes due 2044(h)	250				250
4.15% Senior secured notes due 2046(h)	250				—
Environmental improvement and pollution control revenue bonds:
5.90% Series 1993 due 2023(j)	(j)				(j)
5.70% 1994A Series due 2024(k)	(k)				(k)
1993 Series B-1 due 2028(e)(l)	17				17
Total long-term debt, gross	2,496				2,246
Less: Unamortized discount and premium	(7		)		(5		)
Less: Unamortized debt issuance costs(a)	(18		)		(17		)
Less: Maturities due within one year	(129		)		—
Long-term debt, net	$	2,342			$	2,224
Ameren consolidated long-term debt, net	$	6,880			$	6,085

(a)	Reflects the adoption of the new authoritative accounting guidance for the presentation of debt issuance costs. See Note 1 – Summary of Significant Accounting Policies for additional information.

(b)

These notes are collaterally secured by first mortgage bonds issued by Ameren Missouri under the Ameren Missouri mortgage indenture. The notes have a fall-away lien provision and will remain secured only as long as any first mortgage bonds issued under the Ameren Missouri mortgage indenture remain outstanding. Redemption, purchase, or maturity of all first mortgage bonds, including first mortgage bonds currently outstanding and any that may be issued in the future, would result in a release of the first mortgage bonds currently securing these notes, at which time these notes would become unsecured obligations. Considering the Ameren Missouri senior secured notes currently outstanding, we do not expect the first mortgage bond lien protection associated with these notes to fall away until 2042.

(c)

Ameren Missouri has agreed that so long as any of the 3.90% senior secured notes due 2042 are outstanding, Ameren Missouri will not permit a release date to occur, and so long as any of the 6.70% senior secured notes due 2019, 6.00% senior secured notes due 2018 and 8.45% senior secured notes due 2039 are outstanding, Ameren Missouri will not optionally redeem, purchase, or otherwise retire in full the outstanding first mortgage bonds not subject to release provisions.

(d)	These bonds are collaterally secured by first mortgage bonds issued by Ameren Missouri under the Ameren Missouri mortgage indenture and have a fall-away lien provision similar to that of Ameren Missouri's senior secured notes. The bonds are also backed by an insurance guarantee policy.

(e)	The interest rates, and the periods during which such rates apply, vary depending on our selection of defined rate modes. Maximum interest rates could reach 18% depending on the series of bonds. The bonds are callable at 100% of par value. The average interest rates for 2015 and 2014 were as follows:

	2015		2014
Ameren Missouri 1992 Series due 2022	0.06%		0.10%
Ameren Missouri 1998 Series A due 2033	0.24%		0.26%
Ameren Missouri 1998 Series B due 2033	0.24%		0.27%
Ameren Missouri 1998 Series C due 2033	0.24%		0.26%
Ameren Illinois 1993 Series B-1 due 2028	0.49%		0.21%

(f)	These bonds are first mortgage bonds issued by Ameren Missouri under the Ameren Missouri mortgage bond indenture and are secured by substantially all Ameren Missouri property and franchises. The bonds are callable at 100% of par value. Less than $1 million principal amount of the bonds remain outstanding.

(g)	These notes are collaterally secured by first mortgage bonds issued by Ameren Illinois under the CILCO mortgage indenture. The notes have a fall-away lien provision, and Ameren Illinois could cause these notes to become unsecured at any time by redeeming the pollution control bonds 5.90% Series 1993 due 2023 (of which less than $1 million remains outstanding).

(h)

These notes are collaterally secured by mortgage bonds issued by Ameren Illinois under the Ameren Illinois mortgage indenture. They are secured by substantially all property of the former IP and CIPS. The notes have a fall-away lien provision and will remain secured only as long as any series of first mortgage bonds issued under the Ameren Illinois mortgage indenture remain outstanding. Redemption, purchase, or maturity of all mortgage bonds, including first mortgage bonds currently outstanding and any that may be issued in the future, would result in a release of the mortgage bonds currently securing these notes, at which time these notes would become unsecured obligations. Considering the Ameren Illinois senior secured notes currently outstanding, we do not expect the mortgage bond lien protection associated with these notes to fall away until 2024.

(i)

Ameren Illinois has agreed that so long as any of the 2.70% senior secured notes due 2022 are outstanding, Ameren Illinois will not permit a release date to occur, and so long as any of the 9.75% senior secured notes due 2018, 6.25% senior secured notes due 2018 and 6.125% senior secured notes due 2017 are outstanding, Ameren Illinois will not optionally redeem, purchase or otherwise retire in full the outstanding first mortgage bonds not subject to release provisions; therefore, a release date will not occur so long as any of these notes remain outstanding.

(j)	These bonds are first mortgage bonds issued by Ameren Illinois under the CILCO mortgage indenture. They are secured by substantially all property of the former CILCO. The bonds are callable at 100% of par value. Less than $1 million principal amount of the bonds remain outstanding.

(k)	These bonds are mortgage bonds issued by Ameren Illinois under the Ameren Illinois mortgage indenture. They are secured by substantially all property of the former IP and CIPS. The bonds are callable at 100% of par value. The bonds are also backed by an insurance guarantee policy. Less than $1 million principal amount of the bonds remains outstanding.

(l)	The bonds are callable at 100% of par value.

The following table presents the aggregate maturities of long-term debt, including current maturities, for the Ameren Companies at December 31, 2015:

	Ameren (parent)(a)				Ameren Missouri(a)				Ameren Illinois(a)				Ameren Consolidated
2016	$	—			$	266			$	129			$	395
2017	—				431				250				681
2018	—				383				457				840
2019	—				581				—				581
2020	350				92				—				442
Thereafter	350				2,382				1,660				4,392
Total	$	700			$	4,135			$	2,496			$	7,331

(a)	Excludes unamortized discount and premium and debt issuance costs of $6 million, $25 million, and $25 million at Ameren (parent), Ameren Missouri, and Ameren Illinois, respectively.

All classes of Ameren Missouri’s and Ameren Illinois’ preferred stock are entitled to cumulative dividends, have voting rights, and are not subject to mandatory redemption. The preferred stock of Ameren's subsidiaries was included in "Noncontrolling Interests" on Ameren's consolidated balance sheet. The following table presents the outstanding preferred stock of Ameren Missouri and Ameren Illinois, which is redeemable, at the option of the issuer, at the prices shown below as of December 31, 2015 and 2014:

			Redemption Price(per share)				2015				2014
Ameren Missouri:
Without par value and stated value of $100 per share, 25 million shares authorized
$3.50 Series	130,000 shares		$	110.00			$	13			$	13
$3.70 Series	40,000 shares		104.75				4				4
$4.00 Series	150,000 shares		105.625				15				15
$4.30 Series	40,000 shares		105.00				4				4
$4.50 Series	213,595 shares		110.00			(a)	21				21
$4.56 Series	200,000 shares		102.47				20				20
$4.75 Series	20,000 shares		102.176				2				2
$5.50 Series A	14,000 shares		110.00				1				1
Total							$	80			$	80
Ameren Illinois:
With par value of $100 per share, 2 million shares authorized
4.00% Series	144,275 shares		$	101.00			$	14			$	14
4.08% Series	45,224 shares		103.00				5				5
4.20% Series	23,655 shares		104.00				2				2
4.25% Series	50,000 shares		102.00				5				5
4.26% Series	16,621 shares		103.00				2				2
4.42% Series	16,190 shares		103.00				2				2
4.70% Series	18,429 shares		103.00				2				2
4.90% Series	73,825 shares		102.00				7				7
4.92% Series	49,289 shares		103.50				5				5
5.16% Series	50,000 shares		102.00				5				5
6.625% Series	124,274 shares		100.00				12				12
7.75% Series	4,542 shares		100.00				1				1
Total							$	62			$	62
Total Ameren							$	142			$	142

(a)	In the event of voluntary liquidation, $105.50.

Ameren has 100 million shares of $0.01 par value preferred stock authorized, with no such shares outstanding. Ameren Missouri has 7.5 million shares of $1 par value preference stock authorized, with no such shares outstanding. Ameren Illinois has

2.6 million shares of no par value preferred stock authorized, with no such shares outstanding.

Ameren

In November 2015, Ameren (parent) issued $350 million of 2.70% senior unsecured notes due November 15, 2020, with interest payable semiannually on May 15 and November 15 of each year, beginning May 15, 2016. Ameren (parent) received proceeds of $348 million, which were used to repay a portion of short-term debt.

In November 2015, Ameren (parent) issued $350 million of 3.65% senior unsecured notes due February 15, 2026, with interest payable semiannually on February 15 and August 15 of each year, beginning February 15, 2016. Ameren (parent) received proceeds of $347 million, which were used to repay a portion of short-term debt.

In May 2014, Ameren (parent) repaid at maturity $425 million of its 8.875% senior unsecured notes, plus accrued interest. The notes were repaid with proceeds from commercial paper issuances.

In June 2015, Ameren, Ameren Missouri, and Ameren Illinois filed a Form S-3 shelf registration statement registering the

issuance of an indeterminate amount of certain types of securities. The registration statement became effective immediately upon filing and will expire in June 2018.

Ameren filed a Form S-3 registration statement with the SEC in May 2014, authorizing the offering of 8.6 million additional shares of its common stock under DRPlus, which expires in May 2017. Shares of common stock sold under DRPlus are, at Ameren’s option, newly issued shares, treasury shares, or shares purchased in the open market or in privately negotiated transactions.

In October 2013, Ameren filed a Form S-8 registration statement with the SEC, authorizing the offering of 4 million additional shares of its common stock under its 401(k) plan. Shares of common stock sold under the 401(k) plan are, at Ameren’s option, newly issued shares, treasury shares, or shares purchased in the open market or in privately negotiated transactions.

From 2013 through 2015, Ameren shares for its DRPlus and its 401(k) plans were purchased in the open market.

Ameren Missouri

In February 2016, $260 million principal amount of Ameren Missouri's 5.40% senior secured notes matured and were repaid with cash on hand and commercial paper borrowings.

In April 2015, Ameren Missouri issued $250 million of 3.65% senior secured notes due April 15, 2045, with interest payable semiannually on April 15 and October 15 of each year, beginning October 15, 2015. Ameren Missouri received proceeds of $247 million, which were used to repay outstanding short-term debt, including short-term debt that Ameren Missouri incurred in connection with the repayment of $114 million of its 4.75% senior secured notes that matured on April 1, 2015.

In April 2014, Ameren Missouri issued $350 million of 3.50% senior secured notes due April 15, 2024, with interest payable semiannually on April 15 and October 15 of each year, beginning October 15, 2014. Ameren Missouri received proceeds of $348 million, which were used to repay at maturity $104 million of its 5.50% senior secured notes due May 15, 2014 and to repay a portion of its short-term debt.

For information on Ameren Missouri's capital contributions and return of capital, refer to Capital Contributions and Return of Capital in Note 1 – Summary of Significant Accounting Policies.

Ameren Illinois

In December 2015, Ameren Illinois issued $250 million of 4.15% senior secured notes due March 15, 2046, with interest payable semiannually on March 15 and September 15, beginning March 15, 2016. Ameren Illinois received proceeds of $245 million, which were used to repay a portion of its short-term debt.

In January 2014, Ameren Illinois redeemed the following environmental improvement and pollution control revenue bonds at par value plus accrued interest:

Senior Secured Notes	Principal Amount
5.90% Series 1993 due 2023(a)	$	32
5.70% 1994A Series due 2024(a)	36
1993 Series C-1 5.95% due 2026	35
1993 Series C-2 5.70% due 2026	8
5.40% 1998A Series due 2028	19
5.40% 1998B Series due 2028	33
Total amount redeemed	$	163

(a)	Less than $1 million principal amount of the bonds remains outstanding after redemption.

In June 2014, Ameren Illinois issued $250 million of 4.30% senior secured notes due July 1, 2044, with interest payable semiannually on January 1 and July 1, beginning January 1, 2015. Ameren Illinois received proceeds of $246 million, which were used to repay a portion of its short-term debt.

In December 2014, Ameren Illinois issued $300 million of 3.25% senior secured notes due March 1, 2025, with interest payable semiannually on March 1 and September 1, beginning March 1, 2015. Ameren Illinois received proceeds of $298 million, which were used to repay a portion of its short-term debt.

For information on Ameren Illinois' capital contributions, refer to Capital Contributions and Return of Capital in Note 1 – Summary of Significant Accounting Policies.

Indenture Provisions and Other Covenants

Ameren Missouri’s and Ameren Illinois’ indentures, credit facilities, and articles of incorporation include covenants and provisions related to issuances of first mortgage bonds and preferred stock. Ameren Missouri and Ameren Illinois are required to meet certain ratios to issue additional first mortgage bonds and preferred stock. A failure to achieve these ratios would not result in a default under these covenants and provisions but would restrict the companies’ ability to issue bonds or preferred stock. The following table summarizes the required and actual interest coverage ratios for interest charges, dividend coverage ratios, and bonds and preferred stock issuable as of December 31, 2015, at an assumed interest rate of 5% and dividend rate of 6%.

	Required Interest Coverage Ratio(a)	Actual Interest Coverage Ratio		Bonds Issuable(b)				Required Dividend Coverage Ratio(c)	Actual Dividend Coverage Ratio		Preferred Stock Issuable
Ameren Missouri	>2.0	3.8		$	3,385			>2.5	104.0		$	2,315
Ameren Illinois	>2.0	6.3		3,566			(d)	>1.5	2.6		203			(e)

(a)	Coverage required on the annual interest charges on first mortgage bonds outstanding and to be issued. Coverage is not required in certain cases when additional first mortgage bonds are issued on the basis of retired bonds.

(b)	Amount of bonds issuable based either on required coverage ratios or unfunded property additions, whichever is more restrictive. The amounts shown also include bonds issuable based on retired bond capacity of $946 million and $204 million at Ameren Missouri and Ameren Illinois, respectively.

(c)	Coverage required on the annual dividend on preferred stock outstanding and to be issued, as required in the respective company’s articles of incorporation.

(d)	Amount of bonds issuable by Ameren Illinois based on unfunded property additions and retired bonds solely under the former IP mortgage indenture. The amount of bonds issuable by Ameren Illinois is also subject to the lien restrictions contained in the Illinois Credit Agreement.

(e)	Preferred stock issuable is restricted by the amount of preferred stock that is currently authorized by Ameren Illinois' articles of incorporation.

Ameren's indenture does not require Ameren to comply with any quantitative financial covenants. The indenture does, however, include certain cross-default provisions. Specifically, either (1) the failure by Ameren to pay when due and upon expiration of any applicable grace period any portion of any Ameren indebtedness in excess of $25 million, or (2) the acceleration upon default of the maturity of any Ameren indebtedness in excess of $25 million under any indebtedness agreement, including borrowings under the Credit Agreements or the Ameren commercial paper program, constitutes a default under the indenture, unless such past due or accelerated debt is discharged or the acceleration is rescinded or annulled within a specified period.

Ameren Missouri and Ameren Illinois and certain other nonregistrant Ameren subsidiaries are subject to Section 305(a) of the Federal Power Act, which makes it unlawful for any officer or director of a public utility, as defined in the Federal Power Act, to participate in the making or paying of any dividend from any funds “properly included in capital account.” The FERC has consistently interpreted the provision to allow dividends to be paid as long as (1) the source of the dividends is clearly disclosed, (2) the dividends are not excessive, and (3) there is no self-dealing on the part of corporate officials. At a minimum, Ameren believes that dividends can be paid by its subsidiaries that are public utilities from net income and retained earnings. In addition, under Illinois law, Ameren Illinois may not pay any dividend on its stock unless, among other things, its earnings and

earned surplus are sufficient to declare and pay a dividend after provision is made for reasonable and proper reserves, or unless Ameren Illinois has specific authorization from the ICC.

Ameren Illinois’ articles of incorporation require dividend payments on its common stock to be based on ratios of common stock to total capitalization and other provisions related to certain operating expenses and accumulations of earned surplus. Ameren Illinois has made a commitment to the FERC to maintain a minimum 30% ratio of common stock equity to total capitalization. As of December 31, 2015, Ameren Illinois’ ratio of common stock equity to total capitalization was 51%.

In order for the Ameren Companies to issue securities in the future, they will have to comply with all applicable requirements in effect at the time of any such issuances.

Off-Balance-Sheet Arrangements

At December 31, 2015, none of the Ameren Companies had off-balance-sheet financing arrangements, other than operating leases entered into in the ordinary course of business, letters of credit, and Ameren parent guarantee arrangements on behalf of its subsidiaries. None of the Ameren Companies expect to engage in any significant off-balance-sheet financing arrangements in the near future.

NOTE 6 – OTHER INCOME AND EXPENSES

The following table presents the components of "Other Income and Expenses" in the Ameren Companies’ statements of income (loss) for the years ended December 31, 2015, 2014, and 2013:

	2015				2014				2013
Ameren:(a)
Miscellaneous income:
Allowance for equity funds used during construction	$	30			$	34			$	37
Interest income on industrial development revenue bonds	27				27				27
Interest income (b)	14				10				3
Other	3				8			(c)	2
Total miscellaneous income	$	74			$	79			$	69
Miscellaneous expense:
Donations	$	15			$	10			$	12
Other	15				12				14
Total miscellaneous expense	$	30			$	22			$	26
Ameren Missouri:
Miscellaneous income:
Allowance for equity funds used during construction	$	22			$	32			$	31
Interest income on industrial development revenue bonds	27				27				27
Interest income	1				1				—
Other	2				—				—
Total miscellaneous income	$	52			$	60			$	58
Miscellaneous expense:
Donations	$	5			$	6			$	4
Other	6				6				7
Total miscellaneous expense	$	11			$	12			$	11
Ameren Illinois:
Miscellaneous income:
Allowance for equity funds used during construction	$	8			$	2			$	6
Interest income (b)	12				7				2
Other	1				8			(c)	2
Total miscellaneous income	$	21			$	17			$	10
Miscellaneous expense:
Donations	$	5			$	4			$	4
Other	7				4				5
Total miscellaneous expense	$	12			$	8			$	9

(a)	Includes amounts for Ameren registrant and nonregistrant subsidiaries and intercompany eliminations.

(b)	Includes Ameren Illinois' interest income on the IEIMA revenue requirement reconciliation adjustment regulatory assets.

(c)	Includes Ameren Illinois' income earned in 2014 from customer-requested construction.

NOTE 7 – DERIVATIVE FINANCIAL INSTRUMENTS

We use derivatives to manage the risk of changes in market prices for natural gas, power, and uranium, as well as the risk of changes in rail transportation surcharges through fuel oil hedges. Such price fluctuations may cause the following:

•	an unrealized appreciation or depreciation of our contracted commitments to purchase or sell when purchase or sale prices under the commitments are compared with current commodity prices;

•	market values of natural gas and uranium inventories that differ from the cost of those commodities in inventory; and

•	actual cash outlays for the purchase of these commodities

that differ from anticipated cash outlays.

The derivatives that we use to hedge these risks are governed by our risk management policies for forward contracts, futures, options, and swaps. Our net positions are continually assessed within our structured hedging programs to determine whether new or offsetting transactions are required. The goal of the hedging program is generally to mitigate financial risks while ensuring that sufficient volumes are available to meet our requirements. Contracts we enter into as part of our risk management program may be settled financially, settled by physical delivery, or net settled with the counterparty.

The following table presents open gross commodity contract volumes by commodity type for derivative assets and liabilities as of December 31, 2015 and 2014. As of December 31, 2015, these contracts ran through October 2018, March 2021, May 2032, and January 2019 for fuel oils, natural gas, power, and uranium, respectively.

	Quantity (in millions, except as indicated)
	2015			2014
Commodity	Ameren Missouri	Ameren Illinois	Ameren	Ameren Missouri	Ameren Illinois	Ameren
Fuel oils (in gallons)(a)	35	(b)	35	50	(b)	50
Natural gas (in mmbtu)	30	151	181	28	108	136
Power (in megawatthours)	1	10	11	1	11	12
Uranium (pounds in thousands)	494	(b)	494	332	(b)	332

(a)	Fuel oils consist of heating oil and ultra-low-sulfur diesel.

(b)	Not applicable.

Authoritative accounting guidance regarding derivative instruments requires that all contracts considered to be derivative instruments be recorded on the balance sheet at their fair values, unless the NPNS exception applies. See Note 8 – Fair Value Measurements for discussion of our methods of assessing the fair value of derivative instruments. Many of our physical contracts, such as our purchased power contracts, qualify for the NPNS exception to derivative accounting rules. The revenue or expense on NPNS contracts is recognized at the contract price upon physical delivery.

If we determine that a contract meets the definition of a derivative and is not eligible for the NPNS exception, we review the contract to determine whether it qualifies for hedge accounting. We also consider whether gains or losses resulting from such derivatives qualify for regulatory deferral. Derivative contracts that qualify for regulatory deferral are recorded at fair value, with changes in fair value recorded as regulatory assets or regulatory liabilities in the period in which the change occurs. We

believe derivative losses and gains deferred as regulatory assets and regulatory liabilities are probable of recovery or refund through future rates charged to customers. Regulatory assets and regulatory liabilities are amortized to operating income as related losses and gains are reflected in rates charged to customers. Therefore, gains and losses on these derivatives have no effect on operating income. As of December 31, 2015 and 2014, all contracts that qualify for hedge accounting receive regulatory deferral.

Authoritative accounting guidance permits companies to offset fair value amounts recognized for the right to reclaim cash collateral (a receivable) or the obligation to return cash collateral (a liability) against fair value amounts recognized for derivative instruments that are executed with the same counterparty under a master netting arrangement or similar agreement. The Ameren Companies did not elect to adopt this guidance for any eligible derivative instruments.

The following table presents the carrying value and balance sheet location of all derivative commodity contracts, none of which were designated as hedging instruments, as of December 31, 2015 and 2014:

	Balance Sheet Location		Ameren Missouri			Ameren Illinois			Ameren
2015
Natural gas	Other current assets	$	—		$	1		$	1
	Other assets		1			—			1
Power	Other current assets		16			—			16
	Total assets (a)	$	17		$	1		$	18
Fuel oils	Other current liabilities	$	22		$	—		$	22
	Other deferred credits and liabilities		7			—			7
Natural gas	MTM derivative liabilities		(b)			32			(b)
	Other current liabilities		6			—			38
	Other deferred credits and liabilities		8			18			26
Power	MTM derivative liabilities		(b)			13			(b)
	Other current liabilities		—			—			13
	Other deferred credits and liabilities		—			157			157
Uranium	Other current liabilities		1			—			1
	Total liabilities (c)	$	44		$	220		$	264
2014
Fuel oils	Other current assets	$	2		$	—		$	2
Natural gas	Other current assets		1			1			2
Power	Other current assets		15			—			15
	Total assets (a)	$	18		$	1		$	19
Fuel oils	Other current liabilities	$	22		$	—		$	22
	Other deferred credits and liabilities		7			—			7
Natural gas	MTM derivative liabilities		(b)			31			(b)
	Other current liabilities		6			—			37
	Other deferred credits and liabilities		6			13			19
Power	MTM derivative liabilities		(b)			11			(b)
	Other current liabilities		3			—			14
	Other deferred credits and liabilities		—			131			131
Uranium	Other current liabilities		2			—			2
	Total liabilities (c)	$	46		$	186		$	232

(a)	Because all contracts qualifying for hedge accounting receive regulatory deferral, the cumulative amount of pretax net gains on all derivative instruments is deferred as a regulatory liability.

(b)	Balance sheet line item not applicable to registrant.

(c)	Because all contracts qualifying for hedge accounting receive regulatory deferral, the cumulative amount of pretax net losses on all derivative instruments is deferred as a regulatory asset.

Derivative instruments are subject to various credit-related losses in the event of nonperformance by counterparties to the transaction. Exchange-traded contracts are supported by the financial and credit quality of the clearing members of the respective exchanges and have nominal credit risk. In all other transactions, we are exposed to credit risk. Our credit risk management program involves establishing credit limits and collateral requirements for counterparties, using master netting arrangements or similar agreements, and reporting daily exposure to senior management.

We believe that entering into master netting arrangements or similar agreements mitigates the level of financial loss that could result from default by allowing net settlement of derivative assets and liabilities. We generally enter into the following master netting arrangements: (1) the International Swaps and Derivatives Association Agreement, a standardized financial natural gas and electric contract; (2) the Master Power Purchase and Sale Agreement, created by the Edison Electric Institute and the National Energy Marketers Association, a standardized contract for the purchase and sale of wholesale power; and (3) the North American Energy Standards Board Inc. Agreement, a standardized contract for the purchase and sale of natural gas. These master netting arrangements allow the counterparties to net settle sale and purchase transactions. Further, collateral requirements are calculated at the master netting arrangement or similar agreement level by counterparty.

The following table provides the recognized gross derivative balances and the net amounts of those derivatives subject to an enforceable master netting arrangement or similar agreement as of December 31, 2015 and 2014:

					Gross Amounts Not Offset on the Balance Sheet
Commodity Contracts Eligible to be Offset		Gross Amounts Recognized on the Balance Sheet			Derivative Instruments			Cash Collateral Received/Posted(a)			Net Amount
2015
Assets:
Ameren Missouri	$	17		$	1		$	—		$	16
Ameren Illinois		1			—			—			1
Ameren	$	18		$	1		$	—		$	17
Liabilities:
Ameren Missouri	$	44		$	1		$	8		$	35
Ameren Illinois		220			—			3			217
Ameren	$	264		$	1		$	11		$	252
2014
Assets:
Ameren Missouri	$	18		$	5		$	—		$	13
Ameren Illinois		1			—			—			1
Ameren	$	19		$	5		$	—		$	14
Liabilities:
Ameren Missouri	$	46		$	5		$	5		$	36
Ameren Illinois		186			—			—			186
Ameren	$	232		$	5		$	5		$	222

(a)	Cash collateral received reduces gross asset balances and is included in “Other current liabilities” and “Other deferred credits and liabilities” on the balance sheet. Cash collateral posted reduces gross liability balances and is included in “Other current assets” and “Other assets” on the balance sheet.

Concentrations of Credit Risk

In determining our concentrations of credit risk related to derivative instruments, we review our individual counterparties and categorize each counterparty into groupings according to the primary business in which each engages. We calculate maximum exposures based on the gross fair value of financial instruments, including NPNS and other accrual contracts. These exposures are presented on a gross basis, which include affiliate exposure not eliminated at the consolidated Ameren level. The potential loss on counterparty exposures may be reduced or eliminated by the application of master netting arrangements or similar agreements and collateral held. As of December 31, 2015, if counterparty groups were to fail completely to perform on contracts, Ameren's, Ameren Missouri's, and Ameren Illinois' maximum exposure would have been immaterial with or without consideration of the application of master netting arrangements or similar agreements and collateral held.

Derivative Instruments with Credit Risk-Related Contingent Features

Our commodity contracts contain collateral provisions tied to the Ameren Companies’ credit ratings. If we were to experience an adverse change in our credit ratings, or if a counterparty with reasonable grounds for uncertainty regarding performance of an obligation requested adequate assurance of performance, additional collateral postings might be required. The following table presents, as of December 31, 2015, the aggregate fair value of all derivative instruments with credit risk-related contingent features in a gross liability position, the cash collateral posted, and the aggregate amount of additional collateral that counterparties could require. The additional collateral required is the net liability position allowed under the master netting arrangements or similar agreements assuming (1) the credit risk-related contingent features underlying these arrangements were triggered on December 31, 2015, and (2) those counterparties with rights to do so requested collateral.

	Aggregate Fair Value of Derivative Liabilities(a)				Cash Collateral Posted				Potential Aggregate Amount of Additional Collateral Required(b)
2015
Ameren Missouri	$	87			$	9			$	72
Ameren Illinois	78				3				71
Ameren	$	165			$	12			$	143

(a)	Before consideration of master netting arrangements or similar agreements and including NPNS and other accrual contract exposures.

(b)	As collateral requirements with certain counterparties are based on master netting arrangements or similar agreements, the aggregate amount of additional collateral required to be posted is determined after consideration of the effects of such arrangements.

NOTE 8 – FAIR VALUE MEASUREMENTS

Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. We use various methods to determine fair value, including market, income, and cost approaches. With these approaches, we adopt certain assumptions that market participants would use in pricing the asset or liability, including assumptions about market risk or the risks inherent in the inputs to the valuation. Inputs to valuation can be readily observable, market-corroborated, or unobservable. We use valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs. Authoritative accounting guidance established a fair value hierarchy that prioritizes the inputs used to measure fair value. All financial assets and liabilities carried at fair value are classified and disclosed in one of the following three hierarchy levels:

Level 1: Inputs based on quoted prices in active markets for identical assets or liabilities. Level 1 assets and liabilities are primarily exchange-traded derivatives and assets, including cash and cash equivalents and listed equity securities, such as those held in Ameren Missouri’s nuclear decommissioning trust fund.

The market approach is used to measure the fair value of equity securities held in Ameren Missouri's nuclear decommissioning trust fund. Equity securities in this fund are representative of the S&P 500 index, excluding securities of Ameren Corporation, owners and/or operators of nuclear power plants, and the trustee and investment managers. The S&P 500 index comprises stocks of large-capitalization companies.

Level 2: Market-based inputs corroborated by third-party brokers or exchanges based on transacted market data. Level 2 assets and liabilities include certain assets held in Ameren Missouri’s nuclear decommissioning trust fund, including corporate bonds and other fixed-income securities, United States Treasury and agency securities, and certain over-the-counter derivative instruments, including natural gas and financial power transactions.

Fixed income securities are valued by using prices from independent industry recognized data vendors who provide values that are either exchange-based or matrix-based. The fair value measurements of fixed income securities classified as Level 2 are based on inputs other than quoted prices that are

observable for the asset or liability. Examples are matrix pricing, market corroborated pricing, and inputs such as yield curves and indices. Level 2 fixed income securities in the nuclear decommissioning trust fund are primarily corporate bonds, asset-backed securities, and United States agency bonds.

Derivative instruments classified as Level 2 are valued by corroborated observable inputs, such as pricing services or prices from similar instruments that trade in liquid markets. Our development and corroboration process entails obtaining multiple quotes or prices from outside sources. To derive our forward view to price our derivative instruments at fair value, we average the midpoints of the bid/ask spreads. To validate forward prices obtained from outside parties, we compare the pricing to recently settled market transactions. Additionally, a review of all sources is performed to identify any anomalies or potential errors. Further, we consider the volume of transactions on certain trading platforms in our reasonableness assessment of the averaged midpoint. The value of natural gas derivative contracts is based upon exchange closing prices without significant unobservable adjustments. The value of power derivatives contracts is based upon the use of multiple forward prices provided by third parties. The prices are averaged and shaped to a monthly profile when needed without significant unobservable adjustments.

Level 3: Unobservable inputs that are not corroborated by market data. Level 3 assets and liabilities are valued by internally developed models and assumptions or methodologies that use significant unobservable inputs. Level 3 assets and liabilities include derivative instruments that trade in less liquid markets, where pricing is largely unobservable. We value Level 3 instruments by using pricing models with inputs that are often unobservable in the market, as well as certain internal assumptions. Our development and corroboration process entails obtaining multiple quotes or prices from outside sources. As a part of our reasonableness review, an evaluation of all sources is performed to identify any anomalies or potential errors.

We perform an analysis each quarter to determine the appropriate hierarchy level of the assets and liabilities subject to fair value measurements. Financial assets and liabilities are classified in their entirety according to the lowest level of input that is significant to the fair value measurement. All assets and liabilities whose fair value measurement is based on significant unobservable inputs are classified as Level 3.

The following table describes the valuation techniques and unobservable inputs utilized by the Ameren Companies for the fair value of financial assets and liabilities classified as Level 3 in the fair value hierarchy for the periods ended December 31, 2015 and 2014:

		Fair Value										Weighted
		Assets			Liabilities				Valuation Technique(s)	Unobservable Input	Range	Average
	Level 3 Derivative asset and liability – commodity contracts(a):
2015
	Natural Gas	$	1		$	(1	)		Option model	Volatilities(%)(b)	35 – 55	45
										Nodal basis($/mmbtu)(c)	(0.30) – 0	(0.20)
									Discounted cash flow	Nodal basis($/mmbtu)(b)	(0.10) – 0	(0.10)

		Fair Value										Weighted
		Assets			Liabilities				Valuation Technique(s)	Unobservable Input	Range	Average
										Counterparty credit risk(%)(c)(d)	0.40 – 12	7
										Ameren Missouri credit risk(%)(c)(d)	0.40	(e)
	Power(f)	16			(170		)		Discounted cash flow	Average forward peak and off-peak pricing – forwards/swaps($/MWh)(g)	22 – 39	29
										Estimated auction price for FTRs($/MW)(b)	(270) – 2,057	211
										Nodal basis($/MWh)(g)	(10) – (1)	(3)
										Counterparty credit risk(%)(c)(d)	0.86	(e)
										Ameren Illinois credit risk(%)(c)(d)	0.40	(e)
									Fundamental energy production model	Estimated future gas prices($/mmbtu)(b)	3 – 4	4
										Escalation rate(%)(b)(h)	3	(e)
									Contract price allocation	Estimated renewable energy credit costs($/credit)(b)	5 – 7	6
	Uranium	—			(1		)		Option model	Volatilities(%)(b)	20	(e)
									Discounted cash flow	Average forward uranium pricing($/pound)(b)	35 – 42	37
										Ameren Missouri credit risk(%)(c)(d)	0.40	(e)
2014
	Fuel oils	$	2		$	(8	)		Option model	Volatilities(%)(c)	3 – 39	32
									Discounted cash flow	Ameren Missouri credit risk(%)(c)(d)	0.43	(e)
										Escalation rate(%)(b)(i)	5	(e)
	Natural Gas	1			(2		)		Option model	Volatilities(%)(c)	31 – 144	63
										Nodal basis($/mmbtu)(b)	(0.40) – 0	(0.20)
									Discounted cash flow	Nodal basis($/mmbtu)(b)	(0.40) – 0.10	(0.20)
										Counterparty credit risk(%)(c)(d)	0.43 – 13	3
										Ameren Missouri and Ameren Illinois credit risk(%)(c)(d)	0.43	(e)
	Power(f)	11			(144		)		Discounted cash flow	Average forward peak and off-peak pricing – forwards/swaps($/MWh)(g)	27 – 50	32
										Estimated auction price for FTRs($/MW)(b)	(1,833) – 2,743	171
										Nodal basis($/MWh)(b)	(6) – 0	(2)
										Counterparty credit risk(%)(c)(d)	0.26	(e)
										Ameren Missouri and Ameren Illinois credit risk(%)(c)(d)	0.43	(e)
									Fundamental energy production model	Estimated future gas prices($/mmbtu)(b)	4 – 5	4
										Escalation rate(%)(b)(h)	0 – 1	1
									Contract price allocation	Estimated renewable energy credit costs($/credit)(b)	5 – 7	6
	Uranium	—			(2		)		Discounted cash flow	Average forward uranium pricing($/pound)(b)	35 – 40	36

(a)	The derivative asset and liability balances are presented net of counterparty credit considerations.

(b)	Generally, significant increases (decreases) in this input in isolation would result in a significantly higher (lower) fair value measurement.

(c)	Generally, significant increases (decreases) in this input in isolation would result in a significantly lower (higher) fair value measurement.

(d)	Counterparty credit risk is applied only to counterparties with derivative asset balances. Ameren Missouri and Ameren Illinois credit risk is applied only to counterparties with derivative liability balances.

(e)	Not applicable.

(f)	Power valuations use visible third-party pricing evaluated by month for peak and off-peak demand through 2019. Valuations beyond 2019 use fundamentally modeled pricing by month for peak and off-peak demand.

(g)	The balance at Ameren is comprised of Ameren Missouri and Ameren Illinois power contracts, which respond differently to unobservable input changes because of their opposing positions.

(h)	Escalation rate applies to power prices 2026 and beyond.

(i)	Escalation rate applies to fuel oil prices 2017 and beyond.

In accordance with applicable authoritative accounting guidance, we consider nonperformance risk in our valuation of derivative instruments by analyzing the credit standing of our counterparties and considering any counterparty credit enhancements (e.g., collateral). The guidance also requires that the fair value measurement of liabilities reflect the nonperformance risk of the reporting entity, as applicable. Therefore, we have factored the impact of our credit standing, as well as any potential credit enhancements, into the fair value

measurement of both derivative assets and derivative liabilities. Included in our valuation, and based on current market conditions, is a valuation adjustment for counterparty default derived from market data such as the price of credit default swaps, bond yields, and credit ratings. No gains or losses related to valuation adjustments for counterparty default risk were recorded at Ameren, Ameren Missouri, or Ameren Illinois in 2015, 2014 or 2013. At December 31, 2015 and 2014, the counterparty default risk valuation adjustment related to derivative contracts was immaterial for Ameren, Ameren Missouri, and Ameren

Illinois.

The following table sets forth, by level within the fair value hierarchy, our assets and liabilities measured at fair value on a recurring basis as of December 31, 2015:

			Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1)				Significant Other Observable Inputs (Level 2)				Significant Other Unobservable Inputs (Level 3)				Total
Assets:
Ameren	Derivative assets – commodity contracts(a):
	Natural gas		$	—			$	1			$	1			$	2
	Power		—				—				16				16
	Total derivative assets – commodity contracts		$	—			$	1			$	17			$	18
	Nuclear decommissioning trust fund:
	Cash and cash equivalents		$	4			$	—			$	—			$	4
	Equity securities:
	U.S. large capitalization		364				—				—				364
	Debt securities:
	U.S. Treasury and agency securities		—				109				—				109
	Corporate bonds		—				58				—				58
	Other		—				22				—				22
	Total nuclear decommissioning trust fund		$	368			$	189			$	—			$	557		(b)
	Total Ameren		$	368			$	190			$	17			$	575
Ameren Missouri	Derivative assets – commodity contracts(a):
	Natural gas		$	—			$	—			$	1			$	1
	Power		—				—				16				16
	Total derivative assets – commodity contracts		$	—			$	—			$	17			$	17
	Nuclear decommissioning trust fund:
	Cash and cash equivalents		$	4			$	—			$	—			$	4
	Equity securities:
	U.S. large capitalization		364				—				—				364
	Debt securities:
	U.S. Treasury and agency securities		—				109				—				109
	Corporate bonds		—				58				—				58
	Other		—				22				—				22
	Total nuclear decommissioning trust fund		$	368			$	189			$	—			$	557		(b)
	Total Ameren Missouri		$	368			$	189			$	17			$	574
Ameren Illinois	Derivative assets – commodity contracts(a):
	Natural gas		$	—			$	1			$	—			$	1
Liabilities:
Ameren	Derivative liabilities – commodity contracts(a):
	Fuel oils		$	29			$	—			$	—			$	29
	Natural gas		1				62				1				64
	Power		—				—				170				170
	Uranium		—				—				1				1
	Total Ameren		$	30			$	62			$	172			$	264

			Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1)				Significant Other Observable Inputs (Level 2)				Significant Other Unobservable Inputs (Level 3)				Total
Ameren Missouri	Derivative liabilities – commodity contracts(a):
	Fuel oils		$	29			$	—			$	—			$	29
	Natural gas		—				13				1				14
	Power		—				—				—				—
	Uranium		—				—				1				1
	Total Ameren Missouri		$	29			$	13			$	2			$	44
Ameren Illinois	Derivative liabilities – commodity contracts(a):
	Natural gas		$	1			$	49			$	—			$	50
	Power		—				—				170				170
	Total Ameren Illinois		$	1			$	49			$	170			$	220

(a)	The derivative asset and liability balances are presented net of counterparty credit considerations.

(b)	Balance excludes $(1) million of receivables, payables, and accrued income, net.

The following table sets forth, by level within the fair value hierarchy, our assets and liabilities measured at fair value on a recurring basis as of December 31, 2014:

			Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1)				Significant Other Observable Inputs (Level 2)				Significant Other Unobservable Inputs (Level 3)				Total
Assets:
Ameren	Derivative assets – commodity contracts(a):
	Fuel oils		$	—			$	—			$	2			$	2
	Natural gas		—				1				1				2
	Power		—				4				11				15
	Total derivative assets – commodity contracts		$	—			$	5			$	14			$	19
	Nuclear decommissioning trust fund:
	Cash and cash equivalents		$	1			$	—			$	—			$	1
	Equity securities:
	U.S. large capitalization		364				—				—				364
	Debt securities:
	U.S. Treasury and agency securities		—				102				—				102
	Corporate bonds		—				63				—				63
	Other		—				17				—				17
	Total nuclear decommissioning trust fund		$	365			$	182			$	—			$	547		(b)
	Total Ameren		$	365			$	187			$	14			$	566
Ameren Missouri	Derivative assets – commodity contracts(a):
	Fuel oils		$	—			$	—			$	2			$	2
	Natural gas		—				1				—				1
	Power		—				4				11				15
	Total derivative assets – commodity contracts		$	—			$	5			$	13			$	18
	Nuclear decommissioning trust fund:
	Cash and cash equivalents		$	1			$	—			$	—			$	1
	Equity securities:
	U.S. large capitalization		364				—				—				364
	Debt securities:
	U.S. Treasury and agency securities		—				102				—				102
	Corporate bonds		—				63				—				63
	Other		—				17				—				17
	Total nuclear decommissioning trust fund		$	365			$	182			$	—			$	547		(b)
	Total Ameren Missouri		$	365			$	187			$	13			$	565
Ameren Illinois	Derivative assets – commodity contracts(a):
	Natural gas		$	—			$	—			$	1			$	1

			Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1)				Significant Other Observable Inputs (Level 2)				Significant Other Unobservable Inputs (Level 3)				Total
Liabilities:
Ameren	Derivative liabilities – commodity contracts(a):
	Fuel oils		$	21			$	—			$	8			$	29
	Natural gas		1				53				2				56
	Power		—				1				144				145
	Uranium		—				—				2				2
	Total Ameren		$	22			$	54			$	156			$	232
Ameren Missouri	Derivative liabilities – commodity contracts(a):
	Fuel oils		$	21			$	—			$	8			$	29
	Natural gas		1				10				1				12
	Power		—				1				2				3
	Uranium		—				—				2				2
	Total Ameren Missouri		$	22			$	11			$	13			$	46
Ameren Illinois	Derivative liabilities – commodity contracts(a):
	Natural gas		$	—			$	43			$	1			$	44
	Power		—				—				142				142
	Total Ameren Illinois		$	—			$	43			$	143			$	186

(a)	The derivative asset and liability balances are presented net of counterparty credit considerations.

(b)	Balance excludes $2 million of receivables, payables, and accrued income, net.

The following table summarizes the changes in the fair value of financial assets and liabilities classified as Level 3 in the fair value hierarchy for the year ended December 31, 2015:

		Net Derivative Commodity Contracts
		Ameren Missouri			Ameren Illinois			Ameren
Fuel oils:
Beginning balance at January 1, 2015	$	(6	)	$	(a)		$	(6	)
Realized and unrealized gains (losses) included in regulatory assets/liabilities:		(1	)		(a)			(1	)
Settlements		5			(a)			5
Transfers out of Level 3		2			(a)			2
Ending balance at December 31, 2015	$	—		$	(a)		$	—
Change in unrealized gains (losses) related to assets/liabilities held at December 31, 2015	$	—		$	(a)		$	—
Natural gas:
Beginning balance at January 1, 2015	$	(1	)	$	—		$	(1	)
Realized and unrealized gains (losses) included in regulatory assets/liabilities:		—			1			1
Settlements		1			(1	)		—
Ending balance at December 31, 2015	$	—		$	—		$	—
Change in unrealized gains (losses) related to assets/liabilities held at December 31, 2015	$	—		$	—		$	—
Power:
Beginning balance at January 1, 2015	$	9		$	(142	)	$	(133	)
Realized and unrealized gains (losses) included in regulatory assets/liabilities:		2			(41	)		(39	)
Purchases		29			—			29
Settlements		(23	)		13			(10	)
Transfers out of Level 3		(1	)		—			(1	)
Ending balance at December 31, 2015	$	16		$	(170	)	$	(154	)
Change in unrealized gains (losses) related to assets/liabilities held at December 31, 2015	$	—		$	(39	)	$	(39	)
Uranium:
Beginning balance at January 1, 2015	$	(2	)	$	(a)		$	(2	)
Realized and unrealized gains (losses) included in regulatory assets/liabilities:		(1	)		(a)			(1	)
Settlements		2			(a)			2
Ending balance at December 31, 2015	$	(1	)	$	(a)		$	(1	)
Change in unrealized gains (losses) related to assets/liabilities held at December 31, 2015	$	—		$	(a)		$	—

(a)	Not applicable.

The following table summarizes the changes in the fair value of financial assets and liabilities classified as Level 3 in the fair value hierarchy for the year ended December 31, 2014:

		Net Derivative Commodity Contracts
		Ameren Missouri			Ameren Illinois			Ameren
Fuel oils:
Beginning balance at January 1, 2014	$	5		$	(a)		$	5
Realized and unrealized gains (losses) included in regulatory assets/liabilities:		(9	)		(a)			(9	)
Settlements		(2	)		(a)			(2	)
Ending balance at December 31, 2014	$	(6	)	$	(a)		$	(6	)
Change in unrealized gains (losses) related to assets/liabilities held at December 31, 2014	$	(6	)	$	(a)		$	(6	)
Natural gas:
Beginning balance at January 1, 2014	$	—		$	—		$	—
Realized and unrealized gains (losses) included in regulatory assets/liabilities:		—			1			1
Purchases		—			(2	)		(2	)
Sales		(1	)		—			(1	)
Settlements		—			1			1
Ending balance at December 31, 2014	$	(1	)	$	—		$	(1	)
Change in unrealized gains (losses) related to assets/liabilities held at December 31, 2014	$	—		$	2		$	2
Power:
Beginning balance at January 1, 2014	$	19		$	(108	)	$	(89	)
Realized and unrealized gains (losses) included in regulatory assets/liabilities:		(14	)		(39	)		(53	)
Purchases		34			—			34
Sales		(1	)		—			(1	)
Settlements		(29	)		5			(24	)
Ending balance at December 31, 2014	$	9		$	(142	)	$	(133	)
Change in unrealized gains (losses) related to assets/liabilities held at December 31, 2014	$	—		$	(43	)	$	(43	)
Uranium:
Beginning balance at January 1, 2014	$	(6	)	$	(a)		$	(6	)
Realized and unrealized gains (losses) included in regulatory assets/liabilities:		(1	)		(a)			(1	)
Settlements		5			(a)			5
Ending balance at December 31, 2014	$	(2	)	$	(a)		$	(2	)
Change in unrealized gains (losses) related to assets/liabilities held at December 31, 2014	$	(1	)	$	(a)		$	(1	)

(a)	Not applicable.

Transfers into or out of Level 3 represent either (1) existing assets and liabilities that were previously categorized as a higher level, but were recategorized to Level 3 because the inputs to the model became unobservable during the period, or (2) existing assets and liabilities that were previously classified as Level 3, but were recategorized to a higher level because the lowest significant input became observable during the period. Transfers between Level 1 and Level 3 for fuel oils and between Level 2 and Level 3 for power derivatives were primarily caused by changes in availability of similar financial trades observable on electronic exchanges between the periods. Any reclassifications are reported as transfers out of Level 3 at the fair value measurement reported at the beginning of the period in which the changes occur.

See Note 11 – Retirement Benefits for the fair value hierarchy tables detailing Ameren’s pension and postretirement plan assets as of December 31, 2015, as well as a table summarizing the changes in Level 3 plan assets during 2015.

The Ameren Companies’ carrying amounts of cash and cash equivalents approximate fair value because of the short-term nature of these instruments. They are considered to be Level 1 in the fair value hierarchy. The Ameren Companies' short-term borrowings also approximate fair value because of their short-term nature. Short-term borrowings are considered to be Level 2 in the fair value hierarchy as they are valued based on market rates for similar market transactions. The estimated fair value of long-term debt and preferred stock is based on the quoted market prices for same or similar issuances for companies with similar credit profiles or on the current rates offered to the Ameren Companies for similar financial instruments, which fair value measurement is considered Level 2 in the fair value hierarchy.

The following table presents the carrying amounts and estimated fair values of our long-term debt, capital lease obligations and preferred stock at December 31, 2015 and 2014:

	2015								2014
	Carrying Amount				Fair Value				Carrying Amount				Fair Value
Ameren:(a)
Long-term debt and capital lease obligations (including current portion)(b)	$	7,275			$	7,814			$	6,205			$	7,135
Preferred stock	142				125				142				122
Ameren Missouri:
Long-term debt and capital lease obligations (including current portion)(b)	$	4,110			$	4,449			$	3,981			$	4,518
Preferred stock	80				75				80				73
Ameren Illinois:
Long-term debt (including current portion)(b)	$	2,471			$	2,665			$	2,224			$	2,517
Preferred stock	62				50				62				49

(a)	Preferred stock is recorded in "Noncontrolling Interests" on the consolidated balance sheet.

(b)	Carrying amounts reflect the adoption of the new authoritative accounting guidance for the presentation of debt issuance costs. See Note 1 – Summary of Significant Accounting Policies

NOTE 9 – NUCLEAR DECOMMISSIONING TRUST FUND INVESTMENTS

Ameren Missouri has investments in debt and equity securities that are held in a trust fund for the purpose of funding the decommissioning of its Callaway energy center. We have classified these investments as available for sale, and we have recorded all such investments at their fair market value at December 31, 2015, and 2014. See Note 10 – Callaway Energy Center for additional information.

Investments in the nuclear decommissioning trust fund have a target allocation of 60% to 70% in equity securities, with the balance invested in debt securities.

The following table presents proceeds from the sale and maturities of investments in Ameren Missouri’s nuclear decommissioning trust fund and the gross realized gains and losses resulting from those sales for the years ended

December 31, 2015, 2014, and 2013:

	2015				2014				2013
Proceeds from sales and maturities	$	349			$	391			$	196
Gross realized gains	8				7				7
Gross realized losses	2				2				5

Net realized and unrealized gains and losses are deferred and recorded as a regulatory asset or a regulatory liability on Ameren’s and Ameren Missouri’s balance sheets. This reporting is consistent with the method used to account for the decommissioning costs recovered in rates. Gains or losses associated with assets in the trust fund could result in lower or higher funding requirements for decommissioning costs, which are expected to be reflected in electric rates paid by Ameren Missouri’s customers. See Note 2 – Rate and Regulatory Matters.

The following table presents the costs and fair values of investments in debt and equity securities in Ameren's and Ameren Missouri’s nuclear decommissioning trust fund at December 31, 2015 and 2014:

Security Type	Cost				Gross Unrealized Gain				Gross Unrealized Loss			Fair Value
2015
Debt securities	$	191			$	2		$	4			$	189
Equity securities	147				224				7			364
Cash	4				—				—			4
Other(a)	(1		)		—				—			(1		)
Total	$	341			$	226		$	11			$	556
2014
Debt securities	$	175			$	7		$	—			$	182
Equity securities	138				230				4			364
Cash	1				—				—			1
Other(a)	2				—				—			2
Total	$	316			$	237		$	4			$	549

(a)	Represents payables relating to pending security purchases, net of receivables related to pending security sales and interest.

The following table presents the costs and fair values of investments in debt securities in Ameren's and Ameren Missouri’s nuclear decommissioning trust fund according to their contractual maturities at December 31, 2015:

	Cost				Fair Value
Less than 5 years	$	106			$	105
5 years to 10 years	42				41
Due after 10 years	43				43
Total	$	191			$	189

We have unrealized losses relating to certain available-for-sale investments included in our nuclear decommissioning trust fund, recorded as a regulatory asset as discussed above. Decommissioning will not occur until our nuclear energy center is retired. Ameren Missouri received a license extension from the NRC in March 2015 to extend the Callaway energy center’s operating license to 2044. The following table presents the fair value and the gross unrealized losses of the available-for-sale securities held in Ameren's and Ameren Missouri's nuclear decommissioning trust fund. They are aggregated by investment category and the length of time that individual securities have been in a continuous unrealized loss position at December 31, 2015:

	Less than 12 Months								12 Months or Greater							Total
	Fair Value				Gross Unrealized Losses				Fair Value				Gross Unrealized Losses			Fair Value				Gross Unrealized Losses
Debt securities	$	136		$	3				$	4		$	1			$	140		$	4
Equity securities	16				3				4				4			20				7
Total	$	152		$	6				$	8		$	5			$	160		$	11

NOTE 10 – CALLAWAY ENERGY CENTER

Under the NWPA, the DOE is responsible for disposing of spent nuclear fuel from the Callaway energy center and other commercial nuclear energy centers. Under the NWPA, Ameren Missouri and other owners of nuclear energy centers are responsible for paying the disposal costs. The NWPA established the fee that these utilities pay the federal government for disposing of the spent nuclear fuel at one mill, or one-tenth of one cent, for each kilowatthour generated and sold by those plants. The NWPA also requires the DOE to review the nuclear waste fee annually against the cost of the nuclear waste disposal program and to propose to the United States Congress any fee adjustment necessary to offset the costs of the program. As required by the NWPA, Ameren Missouri and other utilities have entered into standard contracts with the DOE. Consistent with the NWPA and its standard contract, Ameren Missouri had historically collected one mill from its electric customers for each kilowatthour of electricity that it generated and sold from its Callaway energy center. Because the federal government is not meeting its disposal obligation, the collection of this fee is currently suspended.

Although both the NWPA and the standard contract stated that the DOE would begin to dispose of spent nuclear fuel by 1998, the DOE is not meeting its disposal obligation. The DOE's delay in carrying out its obligation to dispose of spent nuclear fuel from the Callaway energy center is not expected to adversely affect the continued operations of the energy center. Ameren Missouri has sufficient capacity in the spent fuel pool and dry spent storage facility at the Callaway energy center to store its spent nuclear fuel generated through the end of the energy center’s operating license in 2044.

As a result of the DOE's failure to begin to dispose of spent nuclear fuel from commercial nuclear energy centers and fulfill its

contractual obligations, Ameren Missouri and other nuclear energy center owners sued the DOE to recover costs, such as certain NRC fees and Missouri ad valorem taxes, incurred for ongoing storage of their spent fuel. The lawsuit resulted in a settlement agreement that provides for annual recovery of additional spent fuel storage and related costs incurred from 2010 through 2016, with the ability to extend the recovery period as mutually agreed upon by the parties. Included in these reimbursements are costs related to the dry spent fuel storage facility at the Callaway energy center, to which Ameren Missouri began transferring spent fuel assemblies in 2015. Ameren Missouri will continue to apply for reimbursement from the DOE for allowable costs associated with the ongoing storage of spent fuel.

Electric utility rates charged to customers provide for the recovery of the Callaway energy center's decommissioning costs, which include decontamination, dismantling, and site restoration costs, over the expected life of the nuclear energy center. Amounts collected from customers are deposited into the external nuclear decommissioning trust fund to provide for the Callaway energy center’s decommissioning. It is assumed that the Callaway energy center site will be decommissioned through the immediate dismantlement method and removed from service. Ameren and Ameren Missouri have recorded an ARO for the Callaway energy center decommissioning costs at fair value, which represents the present value of estimated future cash outflows. Annual decommissioning costs of $7 million are included in the costs used to establish electric rates for Ameren Missouri's customers. Every three years, the MoPSC requires Ameren Missouri to file an updated cost study and funding analysis for decommissioning its Callaway energy center. Following the NRC’s decision in March 2015 to extend the Callaway energy center’s operating license from 2024 to 2044, an updated cost study and a revised funding analysis were filed

with the MoPSC in April 2015. Ameren Missouri’s April 2015 filing supported no change in electric service rates for decommissioning costs. There is no time requirement by which the MoPSC must issue an order regarding the decommissioning cost included in Ameren Missouri’s electric service rates. If the assumed return on trust assets is not earned, we believe that it is probable that any such earnings deficiency will be recovered in rates. The fair value of the trust fund for Ameren Missouri's Callaway energy center is reported as "Nuclear decommissioning trust fund" in Ameren's and Ameren Missouri's balance sheets. This amount is legally restricted and may be used only to fund the costs of nuclear decommissioning. Changes in the fair value of the trust fund are recorded as an increase or decrease to the nuclear decommissioning trust fund, with an offsetting adjustment to the related regulatory liability.

See Note 2 – Rate and Regulatory Matters and Note 9 – Nuclear Decommissioning Trust Fund Investments for additional information related to the Callaway energy center.

NOTE 11 – RETIREMENT BENEFITS

The primary objective of the Ameren pension and postretirement benefit plans is to provide eligible employees with pension and postretirement health care and life insurance benefits. Ameren offers defined benefit pension and postretirement benefit plans covering substantially all of its union employees. Ameren offers defined benefit pension plans covering substantially all of its non-union employees and postretirement benefit plans covering non-union employees hired before October 2015. Ameren uses a measurement date of December 31 for its pension and postretirement benefit plans. Ameren Missouri and Ameren Illinois each participate in Ameren’s single-employer pension and other postretirement plans. Ameren’s qualified pension plan is the Ameren Retirement Plan. Ameren also has an unfunded nonqualified pension plan, the Ameren Supplemental Retirement Plan, which is available to provide certain management employees and retirees with a supplemental benefit when their qualified pension plan benefits are capped in compliance with Internal Revenue Code limitations. Ameren’s

other postretirement plans are the Ameren Retiree Medical Plan and the Ameren Group Life Insurance Plan. Only Ameren subsidiaries participate in the plans listed above.

In December 2013, Ameren completed the divestiture of New AER to IPH. In accordance with the transaction agreement, Ameren retained the pension obligations as of December 2, 2013, associated with the current and former employees of New AER and its subsidiaries who were included in the Ameren Retirement Plan and the Ameren Supplemental Retirement Plan. Ameren also retained the postretirement benefit obligations associated with the employees of New AER and its subsidiaries who were eligible to retire at December 2, 2013, and who were included in the Ameren Retiree Medical Plan and the Ameren Group Life Insurance Plan.

Ameren’s unfunded obligation under its pension and other postretirement benefit plans was $567 million and $710 million as of December 31, 2015, and December 31, 2014, respectively. These net liabilities are recorded in "Other current liabilities," "Pension and other postretirement benefits," and "Other assets" on Ameren's consolidated balance sheet. The primary factor contributing to the decrease in the unfunded obligation during 2015 was a 50 basis point increase in the pension and other postretirement benefit plan discount rates used to determine the present value of the obligation. The decrease in the unfunded obligation also resulted in a decrease to "Regulatory assets" on Ameren's, Ameren Missouri's, and Ameren Illinois' consolidated balance sheet.

The following table presents the net benefit liability recorded on the balance sheets of each of the Ameren Companies as of December 31, 2015 and 2014:

	2015			2014
Ameren(a)	$	567		$	710
Ameren Missouri	236			277
Ameren Illinois	219			278

(a)	Includes amounts for Ameren registrant and nonregistrant subsidiaries.

Ameren recognizes the underfunded status of its pension and postretirement plans as a liability on its consolidated balance sheet, with offsetting entries to accumulated OCI and regulatory assets, in accordance with authoritative accounting guidance. The following table presents the funded status of Ameren's pension and postretirement benefit plans as of December 31, 2015 and 2014. It also provides the amounts included in regulatory assets and accumulated OCI at December 31, 2015 and 2014, that have not been recognized in net periodic benefit costs.

	2015							2014
	Pension Benefits(a)				Postretirement Benefits(a)			Pension Benefits(a)				Postretirement Benefits(a)
Accumulated benefit obligation at end of year	$	3,995		$	(b)			$	4,176		$	(b)
Change in benefit obligation:
Net benefit obligation at beginning of year	$	4,410		$	1,203			$	3,900		$	1,096
Service cost	92				24			79				19
Interest cost	174				48			183				50
Participant contributions	—				8			—				16
Actuarial (gain) loss	(256		)		(133	)		462				84
Settlement	(2		)		—			—				—
Benefits paid	(221		)		(56	)		(214		)		(65	)
Federal subsidy on benefits paid	(b)				—			(b)				3
Net benefit obligation at end of year	4,197				1,094			4,410				1,203
Change in plan assets:
Fair value of plan assets at beginning of year	3,794				1,109			3,461				1,074
Actual return on plan assets	(29		)		(8	)		448				75
Employer contributions	111				18			99				6
Federal subsidy on benefits paid	(b)				—			(b)				3
Participant contributions	—				8			—				16
Settlements	(2		)		—			—				—
Benefits paid	(221		)		(56	)		(214		)		(65	)
Fair value of plan assets at end of year	3,653				1,071			3,794				1,109
Funded status – deficiency	544				23			616				94
Accrued benefit cost at December 31	$	544		$	23			$	616		$	94
Amounts recognized in the balance sheet consist of:
Noncurrent asset(c)	$	—		$	(18	)		$	—		$	—
Current liability(d)	3				2			3				2
Noncurrent liability	541				39			613				92
Net liability recognized	$	544		$	23			$	616		$	94
Amounts recognized in regulatory assets consist of:
Net actuarial (gain) loss	$	395		$	(82	)		$	452		$	(7	)
Prior service cost (credit)	(5		)		(11	)		(6		)		(16	)
Amounts (pretax) recognized in accumulated OCI consist of:
Net actuarial (gain) loss	17				(3	)		29				(5	)
Prior service cost (credit)	—				—			—				(1	)
Total	$	407		$	(96	)		$	475		$	(29	)

(a)	Includes amounts for Ameren registrant and nonregistrant subsidiaries.

(b)	Not applicable.

(c)	Included in "Other assets" on Ameren's consolidated balance sheet.

(d)	Included in "Other current liabilities" on Ameren's consolidated balance sheet.

The following table presents the assumptions used to determine our benefit obligations at December 31, 2015 and 2014:

	Pension Benefits						Postretirement Benefits
	2015			2014			2015			2014
Discount rate at measurement date	4.50	%		4.00	%		4.50	%		4.00	%
Increase in future compensation	3.50			3.50			3.50			3.50
Medical cost trend rate (initial)	(a)			(a)			5.00			5.00
Medical cost trend rate (ultimate)	(a)			(a)			5.00			5.00
Years to ultimate rate	(a)			(a)			—			—

(a)	Not applicable

Ameren determines discount rate assumptions by identifying a theoretical settlement portfolio of high-quality corporate bonds sufficient to provide for a plan's projected benefit payments. The settlement portfolio of bonds is selected from a pool of more than 700 high-quality corporate bonds. A single discount rate is then determined; that rate results in a discounted value of the plan's benefit payments that equates to the market value of the selected bonds. In addition, during 2015, Ameren adopted the Society of Actuaries 2015 Mortality Tables Report and Mortality Improvement Scale. The updated mortality tables assume a lower rate of mortality improvement as compared to the 2014 Mortality Tables Report and Mortality Improvement Scale that Ameren adopted in 2014. The 2015 tables lowered projected improvements in life expectancies for our employees and retirees, resulting in a decrease to our pension and other postretirement benefit obligations.

Funding

Pension benefits are based on the employees’ years of

service, age, and compensation. Ameren’s pension plans are funded in compliance with income tax regulations, federal funding, and other regulatory requirements. As a result, Ameren expects to fund its pension plan at a level equal to the greater of the pension expense or the legally required minimum contribution. Considering its assumptions at December 31, 2015, its investment performance in 2015, and its pension funding policy, Ameren expects to make annual contributions of $40 million to $70 million in each of the next five years, with aggregate estimated contributions of $280 million. We expect Ameren Missouri’s and Ameren Illinois’ portion of the future funding requirements to be 40% and 50%, respectively. These amounts are estimates. They may change based on actual investment performance, changes in interest rates, changes in our assumptions, changes in government regulations, and any voluntary contributions. Our funding policy for postretirement benefits is primarily to fund the Voluntary Employee Beneficiary Association (VEBA) trusts to match the annual postretirement expense.

The following table presents the cash contributions made to our defined benefit retirement plan and to our postretirement plans during 2015, 2014, and 2013:

	Pension Benefits												Postretirement Benefits
	2015				2014				2013				2015				2014				2013
Ameren Missouri	$	47			$	41			$	60			$	8			$	3			$	10
Ameren Illinois	45				39				50				8				2				11
Other	19				19				46				2				1				4
Ameren(a)	111				99				156				18				6				25

(a)	Includes amounts for Ameren registrant and nonregistrant subsidiaries.

Investment Strategy and Policies

Ameren manages plan assets in accordance with the “prudent investor” guidelines contained in ERISA. The investment committee, which includes members of senior management, approves and implements investment strategy and asset allocation guidelines for the plan assets. The investment committee’s goals are twofold: first, to ensure that sufficient funds are available to provide the benefits at the time they are payable; and second, to maximize total return on plan assets and to minimize expense volatility consistent with its tolerance for risk. Ameren delegates the task of investment management to specialists in each asset class. As appropriate, Ameren provides each investment manager with guidelines that specify allowable and prohibited investment types. The investment committee regularly monitors manager performance and compliance with

investment guidelines.

The expected return on plan assets assumption is based on historical and projected rates of return for current and planned asset classes in the investment portfolio. Projected rates of return for each asset class were estimated after an analysis of historical experience, future expectations, and the volatility of the various asset classes. After considering the target asset allocation for each asset class, we adjusted the overall expected rate of return for the portfolio for historical and expected experience of active portfolio management results compared with benchmark returns and for the effect of expenses paid from plan assets. Ameren will use an expected return on plan assets for its pension and postretirement plan assets of 7.00%, in 2016. No plan assets are expected to be returned to Ameren during 2016.

Ameren’s investment committee strives to assemble a portfolio of diversified assets that does not create a significant concentration of risks. The investment committee develops asset allocation guidelines between asset classes, and it creates diversification through investments in assets that differ by type (equity, debt, real estate, private equity), duration, market capitalization, country, style (growth or value) and industry, among other factors. The diversification of assets is displayed in the target allocation table below. The investment committee also routinely rebalances the plan assets to adhere to the diversification goals. The investment committee’s strategy reduces the concentration of investment risk; however, Ameren is still subject to overall market risk. The following table presents our target allocations for 2016 and our pension and postretirement plans’ asset categories as of December 31, 2015 and 2014:

Asset Category	Target Allocation 2016		Percentage of Plan Assets at December 31,
2015			2014
Pension Plan:
Cash and cash equivalents	0% – 5%		1	%		2	%
Equity securities:
U.S. large-capitalization	29% – 39%		34	%		34	%
U.S. small- and mid-capitalization	3% – 13%		7	%		7	%
International and emerging markets	9% – 19%		13	%		12	%
Total equity	51% – 61%		54	%		53	%
Debt securities	35% – 45%		40	%		41	%
Real estate	0% – 9%		5	%		4	%
Private equity	0% – 5%		(a)			(a)
Total			100	%		100	%
Postretirement Plans:
Cash and cash equivalents	0% – 7%		4	%		4	%
Equity securities:
U.S. large-capitalization	34% – 44%		39	%		40	%
U.S. small- and mid-capitalization	2% – 12%		7	%		7	%
International	9% – 19%		13	%		13	%
Total equity	55% – 65%		59	%		60	%
Debt securities	33% – 43%		37	%		36	%
Total			100	%		100	%

(a)	Less than 1% of plan assets.

In general, the United States large-capitalization equity investments are passively managed or indexed, whereas the international, emerging markets, United States small-capitalization, and United States mid-capitalization equity investments are actively managed by investment managers. Debt securities include a broad range of fixed-income vehicles. Debt security investments in high-yield securities, emerging market securities, and non-United-States-dollar-denominated securities are owned by the plans, but in limited quantities to reduce risk. Most of the debt security investments are under active management by investment managers. Real estate investments include private real estate vehicles; however, Ameren does not, by policy, hold direct investments in real estate property. Ameren’s investment in private equity funds is spread among eight different limited partnerships, with invested capital ranging from less than $1 million to $4 million in each, which invest primarily in a diversified number of small United States-based companies. Ameren is seeking to eliminate its private equity investments over time. Additionally, Ameren’s investment committee allows investment managers to use derivatives, such as index futures, exchange traded funds, foreign exchange futures, and options, in certain situations, to increase or to reduce market exposure in an efficient and timely manner.

Fair Value Measurements of Plan Assets

Investments in the pension and postretirement benefit plans were stated at fair value as of December 31, 2015. The fair value of an asset is the amount that would be received upon its sale in an orderly transaction between market participants at the measurement date. Cash and cash equivalents have initial maturities of three months or less and are recorded at cost plus accrued interest. The carrying amounts of cash and cash equivalents approximate fair value because of the short-term nature of these instruments. Investments traded in active markets on national or international securities exchanges are valued at closing prices on the last business day on or before the measurement date. Securities traded in over-the-counter markets are valued based on quoted market prices, broker or dealer quotations, or alternative pricing sources with reasonable levels of price transparency. Investments measured under net asset valuation are based on the fair values of the underlying assets provided by the funds and their administrators. Derivative contracts are valued at fair value, as determined by the investment managers (or independent third parties on behalf of the investment managers), who use proprietary models and take into consideration exchange quotations on underlying instruments, dealer quotations, and other market information. The fair value of real estate is based on annual appraisal reports prepared by an independent real estate appraiser.

The following table sets forth, by level within the fair value hierarchy discussed in Note 8 – Fair Value Measurements, the pension plan assets measured at fair value as of December 31, 2015:

	Quoted Prices in Active Markets for Identified Assets (Level 1)				Significant Other Observable Inputs (Level 2)				Significant Other Unobservable Inputs (Level 3)				Total
Cash and cash equivalents	$	—			$	20			$	—			$	20
Equity securities:
U.S. large-capitalization	—				1,296				—				1,296
U.S. small- and mid-capitalization	268				—				—				268
International and emerging markets	122				369				—				491
Debt securities:
Corporate bonds	—				631				—				631
Municipal bonds	—				104				—				104
U.S. Treasury and agency securities	6				751				—				757
Other	—				5				—				5
Real estate	—				—				168				168
Private equity	—				—				8				8
Total	$	396			$	3,176			$	176			$	3,748
Less: Medical benefit assets at December 31(a)													(123		)
Plus: Net receivables at December 31(b)													28
Fair value of pension plans assets at year end													$	3,653

(a)	Medical benefit (health and welfare) component for accounts maintained in accordance with Section 401(h) of the Internal Revenue Code to fund a portion of the postretirement obligation.

(b)	Receivables related to pending security sales, offset by payables related to pending security purchases.

The following table sets forth, by level within the fair value hierarchy discussed in Note 8 – Fair Value Measurements, the pension plan assets measured at fair value as of December 31, 2014:

	Quoted Prices in Active Markets for Identified Assets or Liabilities (Level 1)				Significant Other Observable Inputs (Level 2)				Significant Other Unobservable Inputs (Level 3)				Total
Cash and cash equivalents	$	—			$	38			$	—			$	38
Equity securities:
U.S. large-capitalization	—				1,331				—				1,331
U.S. small- and mid-capitalization	270				—				—				270
International and emerging markets	134				360				—				494
Debt securities:
Corporate bonds	—				1,026				—				1,026
Municipal bonds	—				175				—				175
U.S. Treasury and agency securities	6				366				—				372
Other	—				31				—				31
Real estate	—				—				147				147
Private equity	—				—				13				13
Derivative assets	1				—				—				1
Total	$	411			$	3,327			$	160			$	3,898
Less: Medical benefit assets at December 31(a)													(125		)
Plus: Net receivables at December 31(b)													21
Fair value of pension plans assets at year end													$	3,794

(a)	Medical benefit (health and welfare) component for accounts maintained in accordance with Section 401(h) of the Internal Revenue Code to fund a portion of the postretirement obligation.

(b)	Receivables related to pending security sales, offset by payables related to pending security purchases.

The following table summarizes the changes in the fair value of the pension plan assets classified as Level 3 in the fair value hierarchy for each of the years ended December 31, 2015 and 2014:

	Beginning Balance at January 1,				Actual Return on Plan Assets Related to Assets Still Held at the Reporting Date				Actual Return on Plan Assets Related to Assets Sold During the Period				Purchases, Sales, and Settlements, Net				Net Transfers into (out of) of Level 3				Ending Balance at December 31,
2015:
Real estate	$	147			$	14			$	—			$	7			$	—			$	168
Private equity	13				(9		)		9				(5		)		—				8
2014:
Real estate	$	131			$	11			$	—			$	5			$	—			$	147
Private equity	15				(9		)		10				(3		)		—				13

The following table sets forth, by level within the fair value hierarchy discussed in Note 8 – Fair Value Measurements, the postretirement benefit plans assets measured at fair value as of December 31, 2015:

	Quoted Prices in Active Markets for Identified Assets (Level 1)				Significant Other Observable Inputs (Level 2)				Significant Other Unobservable Inputs (Level 3)				Total
Cash and cash equivalents	$	61			$	—			$	—			$	61
Equity securities:
U.S. large-capitalization	272				98				—				370
U.S. small- and mid-capitalization	65				—				—				65
International	33				93				—				126
Other	—				7				—				7
Debt securities:
Corporate bonds	—				138				—				138
Municipal bonds	—				114				—				114
U.S. Treasury and agency securities	—				55				—				55
Other	—				40				—				40
Total	$	431			$	545			$	—			$	976
Plus: Medical benefit assets at December 31(a)													123
Less: Net payables at December 31(b)													(28		)
Fair value of postretirement benefit plans assets at year end													$	1,071

(a)	Medical benefit (health and welfare) component for 401(h) accounts to fund a portion of the postretirement obligation. These 401(h) assets are included in the pension plan assets shown above.

(b)	Payables related to pending security purchases, offset by interest receivables and receivables related to pending security sales.

The following table sets forth, by level within the fair value hierarchy discussed in Note 8 – Fair Value Measurements, the postretirement benefit plans assets measured at fair value as of December 31, 2014:

	Quoted Prices in Active Markets for Identified Assets (Level 1)				Significant Other Observable Inputs (Level 2)				Significant Other Unobservable Inputs (Level 3)				Total
Cash and cash equivalents	$	89			$	—			$	—			$	89
Equity securities:
U.S. large-capitalization	291				101				—				392
U.S. small- and mid-capitalization	70				—				—				70
International	37				94				—				131
Other	—				7				—				7
Debt securities:
Corporate bonds	—				105				—				105
Municipal bonds	—				111				—				111
U.S. Treasury and agency securities	—				89				—				89
Other	—				44				—				44
Total	$	487			$	551			$	—			$	1,038
Plus: Medical benefit assets at December 31(a)													125
Less: Net payables at December 31(b)													(54		)
Fair value of postretirement benefit plans assets at year end													$	1,109

(a)	Medical benefit (health and welfare) component for 401(h) accounts to fund a portion of the postretirement obligation. These 401(h) assets are included in the pension plan assets shown above.

(b)	Payables related to pending security purchases, offset by Medicare, interest receivables, and receivables related to pending security sales.

Net Periodic Benefit Cost

The following table presents the components of the net periodic benefit cost of Ameren's pension and postretirement benefit plans during 2015, 2014, and 2013:

	Pension Benefits(a)				Postretirement Benefits(a)
2015
Service cost	$	92			$	24
Interest cost	174				48
Expected return on plan assets	(248		)		(68		)
Amortization of:
Prior service credit	(1		)		(5		)
Actuarial loss	74				5
Settlement Loss	1				—
Net periodic benefit cost	$	92			$	4
2014
Service cost	$	79			$	19
Interest cost	183				50
Expected return on plan assets	(229		)		(65		)
Amortization of:
Prior service credit	(1		)		(5		)
Actuarial (gain) loss	49				(7		)
Net periodic benefit cost (benefit)	$	81			$	(8	)
2013
Service cost	$	91			$	22
Interest cost	163				46
Expected return on plan assets	(218		)		(62		)
Amortization of:
Prior service credit	(2		)		(6		)
Actuarial loss	87				8
Curtailment gain	(12		)		(7		)
Net periodic benefit cost(b)	$	109			$	1

(a)	Includes amounts for Ameren registrant and nonregistrant subsidiaries.

(b)

The net periodic benefit cost includes a $6 million and a $7 million net gain for pension benefits and postretirement benefits, respectively, which was included in "Income (loss) from discontinued operations, net of taxes" on Ameren's consolidated statement of income (loss). This net gain includes the curtailment gain recognized in 2013 as a result of a significant reduction in employees as of the December 2, 2013 closing date of the New AER divestiture. See Note 16 – Divestiture Transactions and Discontinued Operations for additional information on the divestiture.

The estimated amounts that will be amortized from regulatory assets and accumulated OCI into Ameren's net periodic benefit cost in 2016 are as follows:

	Pension Benefits(a)				Postretirement Benefits(a)
Regulatory assets:
Prior service credit	$	(1	)		$	(4	)
Net actuarial loss	46				(3		)
Accumulated OCI:
Net actuarial (gain) loss	(3		)		(2		)
Total	$	42			$	(9	)

(a)	Includes amounts for Ameren registrant and nonregistrant subsidiaries.

Prior service cost is amortized on a straight-line basis over the average future service of active participants benefiting under the plan amendment. The net actuarial (gain) loss subject to amortization is amortized on a straight-line basis over 10 years.

The Ameren Companies are responsible for their share of the pension and postretirement benefit costs. The following table presents the pension costs and the postretirement benefit costs incurred and included in continuing operations for the years ended December 31, 2015, 2014, and 2013:

	Pension Costs												Postretirement Costs
	2015				2014				2013				2015				2014				2013
Ameren Missouri(a)	$	54			$	50			$	69			$	8			$	3			$	8
Ameren Illinois	38				30				41				(3		)		(9		)		—
Other	—				1				5				(1		)		(2		)		—
Ameren(b)	92				81				115				4				(8		)		8

(a)	Does not include the impact of the regulatory tracking mechanism for the difference between the level of pension and postretirement benefit costs incurred by Ameren Missouri under GAAP and the level of such costs included in rates.

(b)	Includes amounts for Ameren registrant and nonregistrant subsidiaries.

The expected pension and postretirement benefit payments from qualified trust and company funds, which reflect expected future service, as of December 31, 2015, are as follows:

	Pension Benefits								Postretirement Benefits
	Paid from Qualified Trust Funds				Paid from Company Funds				Paid from Qualified Trust Funds				Paid from Company Funds
2016	$	233			$	3			$	55			$	2
2017	244				3				58				2
2018	250				3				60				2
2019	257				3				62				2
2020	261				3				65				2
2021 – 2025	1,377				13				341				12

The following table presents the assumptions used to determine net periodic benefit cost for our pension and postretirement benefit plans for the years ended December 31, 2015, 2014, and 2013:

	Pension Benefits									Postretirement Benefits
	2015			2014			2013			2015			2014			2013
Discount rate at measurement date	4.00	%		4.75	%		4.00	%		4.00	%		4.75	%		4.00	%
Expected return on plan assets	7.25			7.25			7.50			7.00			7.00			7.25
Increase in future compensation	3.50			3.50			3.50			3.50			3.50			3.50
Medical cost trend rate (initial)	(a)			(a)			(a)			5.00			5.00			5.00
Medical cost trend rate (ultimate)	(a)			(a)			(a)			5.00			5.00			5.00
Years to ultimate rate	(a)			(a)			(a)			—			—			—

(a)	Not applicable

The table below reflects the sensitivity of Ameren’s plans to potential changes in key assumptions:

	Pension Benefits								Postretirement Benefits
	Service Cost and Interest Cost				Projected Benefit Obligation				Service Cost and Interest Cost				Postretirement Benefit Obligation
0.25% decrease in discount rate	$	(1	)		$	130			$	1			$	37
0.25% increase in salary scale	2				14				—				—
1.00% increase in annual medical trend	—				—				3				44
1.00% decrease in annual medical trend	—				—				(3		)		(44		)

Other

Ameren sponsors a 401(k) plan for eligible employees. The Ameren 401(k) plan covered all eligible employees at December 31, 2015. The plan allows employees to contribute a portion of their compensation in accordance with specific guidelines. Ameren matches a percentage of the employee contributions up to certain limits. The following table presents the portion of the matching contribution to the Ameren 401(k) plan attributable to the continuing operations for each of the Ameren Companies for the years ended December 31, 2015, 2014, and 2013:

	2015				2014				2013
Ameren Missouri	$	16			$	16			$	16
Ameren Illinois	12				11				10
Other	1				1				1
Ameren(a)	29				28				27

(a)	Includes amounts for Ameren registrant and nonregistrant subsidiaries.

NOTE 12 – STOCK-BASED COMPENSATION

The 2014 Incentive Plan is Ameren’s long-term stock compensation plan for eligible employees and directors. The 2006 Incentive Plan was replaced prospectively for new grants beginning in April 2014. The 2014 Incentive Plan provides for a maximum of 8 million common shares to be available for grant to eligible employees and directors. To the extent that the issuance of a share that is subject to an outstanding award under the 2006 Incentive Plan would cause Ameren to exceed the maximum authorized shares under the 2006 Incentive Plan, the issuance of that share will take place under the 2014 Incentive Plan. This will reduce the maximum number of shares that may be granted under the 2014 Incentive Plan. The 2014 Incentive Plan awards may be stock options, stock appreciation rights, restricted stock, restricted stock units, performance shares, performance share units, cash-based awards, and other stock-based awards.

A summary of nonvested shares at December 31, 2015, and changes during the year ended December 31, 2015, under the 2006 Incentive Plan and the 2014 Incentive Plan are presented below:

	Performance Share Units
	Share Units			Weighted-average Fair Value per Share Unit
Nonvested at January 1, 2015	1,162,377			$	35.35
Granted(a)	570,313			52.88
Forfeitures	(1,944	)		34.75
Earned and vested(b)	(705,876	)		33.93
Nonvested at December 31, 2015	1,024,870			$	46.08

(a)	Includes performance share units (share units) granted to certain executive and nonexecutive officers and other eligible employees in 2015 under the 2014 Incentive Plan.

(b)	Includes share units granted in 2013 that vested as of December 31, 2015, that were earned pursuant to the terms of the award grants. Also includes share units that vested due to attainment of retirement eligibility by certain employees. Actual shares issued for retirement-eligible employees will vary depending on actual performance over the three-year measurement period.

Ameren recorded compensation expense of $19 million, $19 million, and $20 million for the years ended December 31, 2015, 2014, and 2013, respectively, and a related tax benefit of $7 million, $7 million, and $8 million for the years ended December 31, 2015, 2014, and 2013, respectively. Ameren settled performance share units of $27 million, $33 million, and $11 million for the years ended December 31, 2015, 2014, and 2013. There were no significant compensation costs capitalized related to the performance share units during the years ended December 31, 2015, 2014, and 2013. As of December 31, 2015, total compensation cost of $21 million related to nonvested awards not yet recognized is expected to be recognized over a weighted-average period of 23 months.

Performance Share Units

A share unit vests and entitles an employee to receive shares of Ameren common stock (plus accumulated dividends) if, at the end of the three-year performance period, certain specified performance or market conditions have been met and if the individual remains employed by Ameren through the required vesting period. The exact number of shares issued pursuant to a share unit varies from 0% to 200% of the target award, depending on actual company performance relative to the performance goals. The vesting period for share units awarded in 2015 extended beyond the three-year performance period to the payout date, while the vesting period for share units awarded in 2013 and 2014 matched the three-year performance period.

The fair value of each share unit awarded in 2015 under the

2014 Incentive Plan was determined to be $52.88, which was based on Ameren's closing common share price of $46.13 at December 31, 2014, and lattice simulations. Lattice simulations are used to estimate expected share payout based on Ameren's total shareholder return for a three-year performance period relative to the designated peer group beginning January 1, 2015. The simulations can produce a greater fair value for the share unit than the applicable closing common share price because they include the weighted payout scenarios in which an increase in the share price has occurred. The significant assumptions used to calculate fair value also included a three-year risk-free rate of 1.10%, volatility of 12% to 18% for the peer group, and Ameren's attainment of a three-year average earnings per share threshold during the performance period.

The fair value of each share unit awarded in 2014, excluding the grants issued in April 2014 for certain executive officers, under the 2006 Incentive Plan and the 2014 Incentive Plan was determined to be $38.90, which was based on Ameren’s closing common share price of $36.16 at December 31, 2013, and lattice simulations. Lattice simulations are used to estimate expected share payout based on Ameren’s total shareholder return for a three-year performance period relative to the designated peer group beginning January 1, 2014. The significant assumptions used to calculate fair value also included a three-year risk-free rate of 0.78%, volatility of 12% to 18% for the peer group, and Ameren’s attainment of a three-year average earnings per share threshold during the performance period.

NOTE 13 – INCOME TAXES

The following table presents the principal reasons for the difference between the effective income tax rate and the statutory federal income tax rate for the years ended December 31, 2015, 2014, and 2013:

	Ameren Missouri			Ameren Illinois			Ameren
2015
Statutory federal income tax rate:	35	%		35	%		35	%
Increases (decreases) from:
Depreciation differences	—			(2	)		(1	)
Amortization of investment tax credit	(1	)		—			(1	)
State tax	3			5			5
Other permanent items	—			(1	)		—
Effective income tax rate	37	%		37	%		38	%
2014
Statutory federal income tax rate:	35	%		35	%		35	%
Increases (decreases) from:
Amortization of investment tax credit	(1	)		—			(1	)
State tax	3			6			4
Other permanent items	—			—			1
Effective income tax rate	37	%		41	%		39	%
2013
Statutory federal income tax rate:	35	%		35	%		35	%
Increases (decreases) from:
Depreciation differences	—			(1	)		—
Amortization of investment tax credit	(1	)		—			(1	)
State tax	3			6			4
Other permanent items	1			—			—
Effective income tax rate	38	%		40	%		38	%

The following table presents the components of income tax expense (benefit) for the years ended December 31, 2015, 2014, and 2013:

	Ameren Missouri				Ameren Illinois				Other				Ameren
2015
Current taxes:
Federal	$	110			$	(83	)		$	(29	)		$	(2	)
State	17				(11		)		(10		)		(4		)
Deferred taxes:
Federal	71				193				35				299
State	16				29				31				76
Deferred investment tax credits, amortization	(5		)		(1		)		—				(6		)
Total income tax expense	$	209			$	127			$	27			$	363
2014
Current taxes:
Federal	$	(13	)		$	(51	)		$	27			$	(37	)
State	(3		)		(2		)		(32		)		(37		)
Deferred taxes:
Federal	222				159				(12		)		369
State	28				38				22				88
Deferred investment tax credits, amortization	(5		)		(1		)		—				(6		)
Total income tax expense	$	229			$	143			$	5			$	377
2013
Current taxes:
Federal	$	136			$	(15	)		$	(239	)	(a)	$	(118	)
State	41				21				(43		)	(a)	19
Deferred taxes:
Federal	64				99				205			(a)	368
State	6				6				36			(a)	48
Deferred investment tax credits, amortization	(5		)		(1		)		—				(6		)
Total income tax expense (benefit)	$	242			$	110			$	(41	)		$	311

(a)	These amounts are substantially related to the reversal of unrecognized tax benefits as a result of IRS guidance related to the deductibility of expenditures to maintain, replace, or improve steam or electric power generation property, along with casualty loss deductions for storm damage. The amounts also reflect the increase in deferred tax expense due to available net operating losses.

The Illinois corporate income tax rate was increased to 9.5% from January 2011 through December 2014. The tax rate decreased to 7.75% on January 1, 2015, and is scheduled to decrease to 7.3% on January 1, 2025.

The following table presents the deferred tax assets and deferred tax liabilities recorded as a result of temporary differences at December 31, 2015 and 2014:

	Ameren Missouri				Ameren Illinois				Other				Ameren
2015
Accumulated deferred income taxes, net liability (asset):
Plant related	$	2,931			$	1,587			$	37			$	4,555
Regulatory assets, net	81				(1		)		—				80
Deferred employee benefit costs	(76		)		(40		)		(91		)		(207		)
Revenue requirement reconciliation adjustments	—				66				—				66
Tax carryforwards	(65		)		(133		)		(405		)		(603		)
Other	(27		)		1				20				(6		)
Total net accumulated deferred income tax liabilities (assets) (a)	$	2,844			$	1,480			$	(439	)		$	3,885
2014
Accumulated deferred income taxes, net liability (asset):
Plant related	$	2,776			$	1,393			$	16			$	4,185
Regulatory assets, net	82				(5		)		1				78
Deferred employee benefit costs	(80		)		(45		)		(95		)		(220		)
Revenue requirement reconciliation adjustments	—				66				3				69
Tax carryforwards	(107		)		(139		)		(429		)		(675		)
Other	86				(22		)		70				134
Total net accumulated deferred income tax liabilities (assets) (a)	$	2,757			$	1,248			$	(434	)		$	3,571

(a)	Reflects the adoption of the new authoritative accounting guidance for the balance sheet classification of deferred income taxes. See Note 1 – Summary of Significant Accounting Policies for additional information.

The following table presents the components of deferred tax assets relating to net operating loss carryforwards, tax credit carryforwards, and charitable contribution carryforwards at December 31, 2015:

	Ameren Missouri				Ameren Illinois				Other				Ameren
Net operating loss carryforwards:
Federal(a)	$	35			$	127			$	245			$	407
State(b)	4				4				38				46
Total net operating loss carryforwards	$	39			$	131			$	283			$	453
Tax credit carryforwards:
Federal(c)	$	26			$	1			$	78			$	105
State(d)	—				1				40				41
State valuation allowance(e)	—				—				(2		)		(2		)
Total tax credit carryforwards	$	26			$	2			$	116			$	144
Charitable contribution carryforwards(f)	$	—			$	—			$	10			$	10
Valuation allowance(e)	—				—				(4		)		(4		)
Total charitable contribution carryforwards	$	—			$	—			$	6			$	6

(a)	Will begin to expire in 2029.

(b)	Will begin to expire in 2023.

(c)	Will begin to expire in 2029.

(d)	Will begin to expire in 2016.

(e)	See Schedule II under Part IV, Item 15, in this report for information on changes in the valuation allowance.

(f)	Will begin to expire in 2016.

The following table presents the components of deferred tax assets relating to net operating loss carryforwards, tax credit carryforwards, and charitable contribution carryforwards at December 31, 2014:

	Ameren Missouri				Ameren Illinois				Other				Ameren
Net operating loss carryforwards:
Federal(a)	$	75			$	127			$	255			$	457
State(b)	11				10				53				74
Total net operating loss carryforwards	$	86			$	137			$	308			$	531
Tax credit carryforwards:
Federal(c)	$	21			$	1			$	77			$	99
State(d)	1				2				33				36
State valuation allowance(e)	(1		)		(1		)		(2		)		(4		)
Total tax credit carryforwards	$	21			$	2			$	108			$	131
Charitable contribution carryforwards(f)	$	—			$	—			$	19			$	19
Valuation allowance(e)	—				—				(6		)		(6		)
Total charitable contribution carryforwards	$	—			$	—			$	13			$	13

(a)	Will begin to expire in 2028

(b)	Will begin to expire in 2019.

(c)	Will begin to expire in 2029.

(d)	Began to expire in 2013.

(e)	See Schedule II under Part IV, Item 15, in this report for information on changes in the valuation allowance.

(f)	Began to expire in 2013.

Uncertain Tax Positions

A reconciliation of the change in the unrecognized tax benefit balance during the years ended December 31, 2013, 2014, and 2015, is as follows:

	Ameren Missouri				Ameren Illinois				Other				Ameren
Unrecognized tax benefits – January 1, 2013	$	136			$	13			$	7			$	156
Increases based on tax positions prior to 2013	—				2				5				7
Decreases based on tax positions prior to 2013	(122		)		(16		)		(5		)		(143		)
Increases based on tax positions related to 2013	16				—				53			(a)	69
Changes related to settlements with taxing authorities	—				—				—				—
Decreases related to the lapse of statute of limitations	1				—				—				1
Unrecognized tax benefits – December 31, 2013	$	31			$	(1	)		$	60			$	90
Increases based on tax positions prior to 2014	1				1				4				6
Decreases based on tax positions prior to 2014	(32		)		(1		)		(9		)		(42		)
Increases based on tax positions related to 2014	—				—				—				—
Changes related to settlements with taxing authorities	—				—				—				—
Increases related to the lapse of statute of limitations	—				—				—				—
Unrecognized tax benefits – December 31, 2014	$	—			$	(1	)		$	55			$	54
Increases based on tax positions prior to 2015	—				1				1				2
Decreases based on tax positions prior to 2015	—				—				(56		)	(a)	(56		)
Increases based on tax positions related to 2015	—				—				—				—
Changes related to settlements with taxing authorities	—				—				—				—
Increases related to the lapse of statute of limitations	—				—				—				—
Unrecognized tax benefits – December 31, 2015	$	—			$	—			$	—			$	—
Total unrecognized tax benefits that, if recognized, would affect the effective tax rates as of December 31, 2013	$	3			$	—			$	51		(a)	$	54
Total unrecognized tax benefits (detriments) that, if recognized, would affect the effective tax rates as of December 31, 2014	$	—			$	(1	)		$	53		(a)	$	52
Total unrecognized tax benefits that, if recognized, would affect the effective tax rates as of December 31, 2015	$	—			$	—			$	—			$	—

(a)	Primarily due to tax positions relating to the New AER divestiture. The income statement impact of this unrecognized tax benefit was included in "Income (loss) from discontinued operations, net of taxes" on Ameren's consolidated statement of income (loss). See Note 16 – Divestiture Transactions and Discontinued Operations for additional information.

The Ameren Companies recognize interest charges (income) and penalties accrued on tax liabilities on a pretax basis as interest charges (income) or miscellaneous expense, respectively, in the statements of income.

A reconciliation of the change in the liability for interest on unrecognized tax benefits during the years ended December 31, 2013, 2014, and 2015, is as follows:

	Ameren Missouri				Ameren Illinois				Other				Ameren
Liability for interest – January 1, 2013	$	8			$	1			$	(3	)		$	6
Interest charges (income) for 2013	(8		)		(1		)		4				(5		)
Liability for interest – December 31, 2013	$	—			$	—			$	1			$	1
Interest charges (income) for 2014	—				—				(1		)		(1		)
Liability for interest – December 31, 2014	$	—			$	—			$	—			$	—
Interest charges (income) for 2015	—				—				—				—
Liability for interest – December 31, 2015	$	—			$	—			$	—			$	—

As of December 31, 2013, 2014, and 2015, the Ameren Companies have accrued no amount for penalties with respect to unrecognized tax benefits.

In 2015, final settlements for tax years 2012 and 2013 were reached with the IRS. There were no uncertain tax positions related to the 2012 tax year, as of December 31, 2014, so this settlement did not affect the amount of recorded unrecognized tax benefits during 2015. The settlement related to the 2013 tax year resolved the uncertain tax position associated with the final tax basis of New AER and the related tax benefit resulting from the divested merchant generation business. The settlement resulted in a reduction of Ameren's unrecognized tax benefits of $53 million and an increase to net income from discontinued operations. See Note 16 – Divestiture Transactions and Discontinued Operations for additional information.

In 2014, final settlements for tax years 2007 through 2011 were reached with the IRS. These settlements, which resolved the uncertain tax positions associated with the timing of research tax deductions for these years, resulted in a decrease in Ameren’s and Ameren Missouri’s unrecognized tax benefits of $20 million, and $13 million, respectively. In addition, the settlement for tax years 2007 through 2011 provided certainty for the previously uncertain tax positions associated with the timing of research tax deductions for the remaining open tax years of 2012, 2013, and 2014. The certainty provided from the settlement resulted in an $18 million decrease in both Ameren’s and Ameren Missouri’s unrecognized tax benefits. The settlement also resulted in a $2 million increase to Ameren’s state unrecognized tax benefits. The net reduction in unrecognized tax benefits in 2014 did not materially affect income tax expense for the Ameren Companies.

In 2013, unrecognized tax benefits related to the deductibility of expenditures to maintain, replace, or improve steam or electric power generation property, along with casualty loss deductions for storm damage, were reduced by $103 million, $95 million, and $5 million for Ameren, Ameren Missouri, and Ameren Illinois, respectively. This reduction in unrecognized tax benefits did not affect income tax expense for the Ameren Companies. However, the liability for interest related to these unrecognized tax benefits was released in 2013. In 2013, Ameren adopted an accounting method change as a result of guidance issued by the IRS, with respect to the amount and timing of the deductions to maintain, replace, or improve generation property.

State income tax returns are generally subject to examination for a period of three years after filing. The state impact of any federal changes remains subject to examination by various states for up to one year after formal notification to the states. The Ameren Companies currently do not have material state income tax issues under examination, administrative appeals, or litigation.

Ameren Missouri has an uncertain tax position tracker. Under Missouri's regulatory framework, uncertain tax positions do not reduce Ameren Missouri's electric rate base. When an uncertain income tax position liability is resolved, the MoPSC requires, through the uncertain tax position tracker, the creation of a regulatory asset or regulatory liability to reflect the time value, using the weighted-average cost of capital included in each of the electric rate orders in effect before the tax position was resolved, of the difference between the uncertain tax position liability that was excluded from rate base and the final tax liability. The resulting regulatory asset or liability will affect earnings in the year it is created and then will be amortized over three years, beginning on the effective date of new rates established in the next electric rate case.

NOTE 14 – RELATED PARTY TRANSACTIONS

In the normal course of business, the Ameren Companies have engaged in, and may in the future engage in, affiliate transactions. These transactions primarily consist of natural gas and power purchases and sales, services received or rendered, and borrowings and lendings. Transactions between affiliates are reported as intercompany transactions on their financial statements, but are eliminated in consolidation for Ameren’s financial statements. Below are the material related party agreements.

Electric Power Supply Agreements

Ameren Illinois must acquire capacity and energy sufficient to meet its obligations to customers. Ameren Illinois uses periodic RFP processes that are administered by the IPA and approved by the ICC, to contract capacity and energy on behalf of its customers. Ameren Missouri participates in the RFP process and has been a winning supplier for certain periods.

Capacity Supply Agreements

In 2010, Ameren Missouri contracted to supply a portion of Ameren Illinois’ capacity requirements for less than $1 million for the period from June 1, 2010, through May 31, 2013. In a procurement event in 2012, Ameren Missouri contracted to supply a portion of Ameren Illinois' capacity requirements for $1 million and $3 million for the 12 months ending May 31, 2014, and 2015, respectively. In a procurement event in 2015, Ameren Missouri contracted to supply a portion of Ameren Illinois' capacity requirements for $15 million for the 12 months ending May 31, 2017.

Energy Swaps and Energy Products

As a result of an IPA procurement event in 2011, Ameren Missouri and Ameren Illinois entered into energy product agreements by which Ameren Missouri agreed to sell and Ameren Illinois agreed to purchase approximately 40,800 megawatthours at approximately $29 per megawatthour during the 12 months ended May 31, 2013, and approximately 40,800 megawatthours at approximately $28 per megawatthour during the 12 months ended May 31, 2014. The energy product agreements for the period ended May 31, 2013, were for off-peak hours only.

As a result of an IPA procurement event in 2014, Ameren Missouri and Ameren Illinois entered into energy product agreements by which Ameren Missouri agreed to sell and Ameren Illinois agreed to purchase approximately 168,400 megawatthours at approximately $51 per megawatthour during the period of January 1, 2015, through February 28, 2017.

As a result of an IPA procurement event in April 2015, Ameren Missouri and Ameren Illinois entered into energy product agreements by which Ameren Missouri agreed to sell and Ameren Illinois agreed to purchase 667,000 megawatthours at an average price of $36 per megawatthour during the period of June 1, 2015, through June 30, 2017. Also in September 2015, Ameren Missouri and Ameren Illinois entered into energy product agreements by which Ameren Missouri agreed to sell and Ameren Illinois agreed to purchase 339,000 megawatthours at an average price of $38 per megawatthour during the period of November 1, 2015, through May 31, 2018.

Interconnection and Transmission Agreements

Ameren Missouri and Ameren Illinois are parties to an interconnection agreement for the use of their respective transmission lines and other facilities for the distribution of power. These agreements have no contractual expiration date, but may be terminated by either party with three years’ notice.

Support Services Agreements

Ameren Services provides support services to its affiliates. The costs of support services, including wages, employee benefits, professional services, and other expenses, are based on, or are an allocation of, actual costs incurred. The support services agreement can be terminated at any time by the mutual agreement of Ameren Services and that affiliate or by either party with 60 days' notice before the end of a calendar year.

In addition, Ameren Missouri and Ameren Illinois provide affiliates, primarily Ameren Services, with access to their facilities for administrative purposes. The costs of the rent and facility services are based on, or are an allocation of, actual costs incurred.

Separately, Ameren Missouri and Ameren Illinois provide storm-related and miscellaneous support services to each other on an as-needed basis.

Transmission Services

Ameren Illinois takes transmission service from MISO for the retail load it serves in the AMIL pricing zone. ATXI is one of the

transmission owners in the AMIL pricing zone. Accordingly, ATXI receives transmission payments from Ameren Illinois through the MISO billing process.

Money Pool

See Note 4 – Short-term Debt and Liquidity and Note 5 – Long-term Debt and Equity Financings for a discussion of affiliate borrowing arrangements.

Collateral Postings

Under the terms of the Illinois power procurement agreements entered into through RFP processes administered by the IPA, suppliers must post collateral under certain market conditions to protect Ameren Illinois in the event of nonperformance. The collateral postings are unilateral, which means that only the suppliers can be required to post collateral. Therefore, Ameren Missouri, as a winning supplier in the RFP process, may be required to post collateral. As of December 31, 2015 and 2014, there were no collateral postings required of Ameren Missouri related to the Illinois power procurement agreements.

Tax Allocation Agreement

See Note 1 – Summary of Significant Accounting Policies for a discussion of the tax allocation agreement. At December 31, 2015 and 2014, Ameren Missouri accrued capital contributions from Ameren (parent) of $38 million and $9 million, respectively, pursuant to the tax allocation agreement.

The following table presents the impact on Ameren Missouri and Ameren Illinois of related party transactions for the years ended December 31, 2015, 2014, and 2013. It is based primarily on the agreements discussed above and the money pool arrangements discussed in Note 4 – Short-term Debt and Liquidity.

Agreement	Income Statement Line Item				Ameren Missouri			Ameren Illinois
Ameren Missouri power supply agreements	Operating Revenues		2015	$	15		$	(a)
with Ameren Illinois			2014		5			(a)
			2013		3			(a)
Ameren Missouri and Ameren Illinois	Operating Revenues		2015		25			4
rent and facility services			2014		21			2
			2013		21			1
Ameren Missouri and Ameren Illinois	Operating Revenues		2015		2			(b)
miscellaneous support services			2014		1			(b)
			2013		1			3
Total Operating Revenues			2015	$	42		$	4
			2014		27			2
			2013		25			4
Ameren Illinois power supply	Purchased Power		2015	$	(a)		$	15
agreements with Ameren Missouri			2014		(a)			5
			2013		(a)			3
Ameren Illinois transmission	Purchased Power		2015		(a)			2
services with ATXI			2014		(a)			2
			2013		(a)			2
Total Purchased Power			2015	$	(a)		$	17
			2014		(a)			7
			2013		(a)			5
Ameren Services support services	Other Operations and		2015	$	131		$	119
agreement	Maintenance		2014		124			109
			2013		116			93
Total Other Operations and			2015	$	131		$	119
Maintenance Expenses			2014		124			109
			2013		116			93
Money pool borrowings (advances)	Interest (Charges)		2015	$	(b)		$	(b)
	Income		2014		(b)			(b)
			2013		(b)			(b)

(a)	Not applicable.

(b)	Amount less than $1 million.

NOTE 15 – COMMITMENTS AND CONTINGENCIES

We are involved in legal, tax, and regulatory proceedings before various courts, regulatory commissions, authorities, and governmental agencies with respect to matters that arise in the ordinary course of business, some of which involve substantial amounts of money. We believe that the final disposition of these proceedings, except as otherwise disclosed in these notes to our financial statements, will not have a material adverse effect on our results of operations, financial position, or liquidity.

See also Note 1 – Summary of Significant Accounting Policies, Note 2 – Rate and Regulatory Matters, Note 10 – Callaway Energy Center, and Note 14 – Related Party Transactions in this report.

Callaway Energy Center

The following table presents insurance coverage at Ameren Missouri’s Callaway energy center at December 31, 2015. The property coverage and the nuclear liability coverage must be renewed on April 1 and January 1, respectively, of each year.

Type and Source of Coverage	Maximum Coverages				Maximum Assessments
Public liability and nuclear worker liability:
American Nuclear Insurers	$	375			$	—
Pool participation	13,114			(a)	127			(b)
	$	13,489		(c)	$	127
Property damage:
Nuclear Electric Insurance Limited	$	2,750		(d)	$	27		(e)
European Mutual Association for Nuclear Insurance	500			(f)	—
	$	3,250			$	27
Replacement power:
Nuclear Electric Insurance Limited	$	490		(g)	$	10		(e)

(a)	Provided through mandatory participation in an industrywide retrospective premium assessment program.

(b)	Retrospective premium under the Price-Anderson Act. This is subject to retrospective assessment with respect to a covered loss in excess of $375 million in the event of an incident at any licensed United States commercial reactor, payable at $19 million per year.

(c)

Limit of liability for each incident under the Price-Anderson liability provisions of the Atomic Energy Act of 1954, as amended. A company could be assessed up to $127 million per incident for each licensed reactor it operates, with a maximum of $19 million per incident to be paid in a calendar year for each reactor. This limit is subject to change to account for the effects of inflation and changes in the number of licensed reactors.

(d)	NEIL provides $2.25 billion in property damage, decontamination, and premature decommissioning insurance for both radiation and nonradiation events. An additional $500 million is provided for radiation events only for a total of $2.75 billion.

(e)	All NEIL-insured plants could be subject to assessments should losses exceed the accumulated funds from NEIL.

(f)	European Mutual Association for Nuclear Insurance provides $500 million in excess of the $2.75 billion and $2.25 billion property coverage for radiation and nonradiation events, respectively, provided by NEIL.

(g)	Provides replacement power cost insurance in the event of a prolonged accidental outage. Weekly indemnity is up to $4.5 million for 52 weeks, which commences after the first twelve weeks of an outage, plus up to $3.6 million per week for a minimum of 71 weeks thereafter, for a total not exceeding the policy limit of $490 million. Nonradiation events are sub-limited to $328 million.

The Price-Anderson Act is a federal law that limits the liability for claims from an incident involving any licensed United States commercial nuclear energy center. The limit is based on the number of licensed reactors. The limit of liability and the maximum potential annual payments are adjusted at least every five years for inflation to reflect changes in the Consumer Price Index. The most recent five-year inflationary adjustment became effective in September 2013. Owners of a nuclear reactor cover this exposure through a combination of private insurance and mandatory participation in a financial protection pool, as established by the Price-Anderson Act.

Losses resulting from terrorist attacks on nuclear facilities are covered under NEIL’s policies, subject to an industrywide aggregate policy coverage limit of $3.24 billion within a 12-month period, or $1.83 billion for events not involving radiation contamination.

If losses from a nuclear incident at the Callaway energy center exceed the limits of, or are not covered by, insurance or if coverage is unavailable, Ameren Missouri is at risk for any uninsured losses. If a serious nuclear incident were to occur, it could have a material adverse effect on Ameren’s and Ameren Missouri’s results of operations, financial position, and liquidity.

Leases

We lease various facilities, office equipment, plant equipment, and rail cars under capital and operating leases. The following table presents our lease obligations at December 31, 2015:

	2016				2017				2018				2019				2020				After 5 Years				Total
Ameren:(a)
Minimum capital lease payments(b)	$	33			$	33			$	32			$	32			$	32			$	329			$	491
Less amount representing interest	27				27				26				25				25				73				203
Present value of minimum capital lease payments	$	6			$	6			$	6			$	7			$	7			$	256			$	288
Operating leases(c)	14				13				12				12				11				30				92
Total lease obligations	$	20			$	19			$	18			$	19			$	18			$	286			$	380
Ameren Missouri:
Minimum capital lease payments(b)	$	33			$	33			$	32			$	32			$	32			$	329			$	491
Less amount representing interest	27				27				26				25				25				73				203
Present value of minimum capital lease payments	$	6			$	6			$	6			$	7			$	7			$	256			$	288
Operating leases(c)	12				11				11				11				10				29				84
Total lease obligations	$	18			$	17			$	17			$	18			$	17			$	285			$	372
Ameren Illinois:
Operating leases(c)	$	1			$	1			$	1			$	1			$	1			$	1			$	6

(a)	Includes amounts for Ameren registrant and nonregistrant subsidiaries and intercompany eliminations.

(b)	See Properties under Part I, Item 2, and Note 3 – Property and Plant, Net, of this report for additional information.

(c)	Amounts related to certain land-related leases have indefinite payment periods. The annual obligations of $3 million, $2 million, and $1 million for Ameren, Ameren Missouri, and Ameren Illinois for these items are included in the 2016 through 2020 columns, respectively.

The following table presents total rental expense included in operating expenses for the years ended December 31, 2015, 2014, and 2013:

	2015				2014				2013
Ameren(a)	$	36			$	37			$	32
Ameren Missouri	34				32				29
Ameren Illinois	28				25				21

(a)	Includes amounts for Ameren registrant and nonregistrant subsidiaries and intercompany eliminations.

Other Obligations

To supply a portion of the fuel requirements of our energy centers, we have entered into various long-term commitments for the procurement of coal, natural gas, nuclear fuel, and methane gas. We also have entered into various long-term commitments for purchased power and natural gas for distribution. The table below presents our estimated fuel, purchased power, and other commitments for fuel at December 31, 2015. Ameren’s and Ameren Missouri’s purchased power commitments include a 102-megawatt power purchase agreement with a wind farm operator, which expires in 2024. Ameren’s and Ameren Illinois’ purchased power commitments include the Ameren Illinois power purchase agreements entered into as part of the IPA-administered power procurement process. Included in the Other column are minimum purchase commitments under contracts for equipment, design and construction, and meter reading services at December 31, 2015.

	Coal				Natural Gas(a)				Nuclear Fuel				Purchased Power(b)				Methane Gas				Other				Total
Ameren:(c)
2016	$	664			$	249			$	51			$	241			$	3			$	115			$	1,323
2017	685				190				46				147				4				73				1,145
2018	204				127				68				72				5				55				531
2019	110				89				24				58				5				56				342
2020	—				43				51				58				6				57				215
Thereafter	—				60				108				539				71				350				1,128
Total	$	1,663			$	758			$	348			$	1,115			$	94			$	706			$	4,684
Ameren Missouri:
2016	$	664			$	46			$	51			$	23			$	3			$	46			$	833
2017	685				36				46				23				4				32				826
2018	204				24				68				23				5				28				352
2019	110				14				24				23				5				29				205
2020	—				10				51				23				6				30				120
Thereafter	—				23				108				84				71				183				469
Total	$	1,663			$	153			$	348			$	199			$	94			$	348			$	2,805
Ameren Illinois:
2016	$	—			$	203			$	—			$	218			$	—			$	31			$	452
2017	—				154				—				124				—				25				303
2018	—				103				—				49				—				24				176
2019	—				75				—				35				—				27				137
2020	—				33				—				35				—				27				95
Thereafter	—				37				—				455				—				167				659
Total	$	—			$	605			$	—			$	916			$	—			$	301			$	1,822

(a)	Includes amounts for generation and for distribution.

(b)	The purchased power amounts for Ameren and Ameren Illinois include agreements through 2032 for renewable energy credits with various renewable energy suppliers. The agreements contain a provision that allows Ameren Illinois to reduce the quantity purchased in the event that Ameren Illinois would not be able to recover the costs associated with the renewable energy credits.

(c)	Includes amounts for Ameren registrant and nonregistrant subsidiaries.

Environmental Matters

We are subject to various environmental laws and regulations enforced by federal, state, and local authorities. From the beginning phases of siting and development to the operation of electric generation, transmission, and distribution facilities and natural gas storage, transmission, and distribution facilities, our activities involve compliance with diverse environmental laws and regulations. These laws and regulations address emissions, discharges to water, water usage, impacts to air, land, and water, and chemical and waste handling. Complex and lengthy processes are required to obtain and renew approvals, permits, and licenses for new, existing or modified facilities. Additionally, the use and handling of various chemicals or hazardous materials require release prevention plans and emergency response procedures.

The EPA has promulgated several environmental

regulations that will have a significant impact on the electric utility industry. Over time, compliance with these regulations could be costly for certain companies, including Ameren Missouri, that operate coal-fired power plants. Significant new rules include the regulation of CO2 emissions from existing power plants through the Clean Power Plan and from new power plants through the revised NSPS; the CSAPR, which requires further reductions of SO2 emissions and NOx emissions from power plants; a regulation governing management and storage of CCR; the MATS, which require reduction of emissions of mercury, toxic metals, and acid gases from power plants; revised NSPS for particulate matter, SO2, and NOx emissions from new sources; new effluent standards applicable to wastewater discharges from power plants and new regulations under the Clean Water Act that could require significant capital expenditures, such as modifications to water intake structures or new cooling towers at Ameren Missouri’s energy centers. The EPA also periodically

reviews and revises national ambient air quality standards, including those standards associated with emissions from power plants, such as particulate matter, ozone, SO2 and NOx. Certain of these new regulations are being or are likely to be challenged through litigation, so their ultimate implementation, as well as the timing of any such implementation, is uncertain. Although many details of future regulations are unknown, individually or the combined effects of new environmental regulations could result in significant capital expenditures and increased operating costs for Ameren and Ameren Missouri. Compliance with all of these environmental laws and regulations could be prohibitively expensive, result in the closure or alteration of the operation of some of Ameren Missouri’s energy centers, or require capital investment. Ameren and Ameren Missouri expect that these costs would be recoverable through rates, subject to MoPSC prudence review, but the nature and timing of costs could result in regulatory lag.

Ameren Missouri's current plan for compliance with existing environmental regulations for air emissions includes burning ultra-low-sulfur coal and installing new or optimizing existing pollution control equipment. Ameren and Ameren Missouri estimate that they will need to make capital expenditures of $600 million to $700 million in the aggregate from 2016 through 2020 in order to comply with existing environmental regulations. Ameren Missouri may be required to install additional air emissions controls within the next six to 10 years. This estimate includes our capital expenditures required for the CCR regulations that were published in 2015, the rule applicable to cooling water intake structures at existing power plants under the Clean Water Act, and the effluent limitation guidelines applicable to steam electric generating units under the Clean Water Act, all of which are discussed below. These estimates do not include the impacts of the Clean Power Plan discussed below. Considerable uncertainty remains in these estimates. The actual amount of capital expenditures required to comply with existing environmental regulations may vary substantially from the above estimate due to uncertainty as to the precise compliance strategies that will be used and their ultimate cost, among other things.

The following sections describe the more significant new environmental laws and rules and environmental enforcement and remediation matters that affect or could affect our operations.

Clean Air Act

Federal and state laws require significant reductions in SO2 and NOx through either emission source reductions or the use and retirement of emission allowances. The CSAPR became effective in 2015. There will be further emission reduction requirements in 2017 and potentially more in subsequent years. To achieve compliance with CSAPR, Ameren Missouri burns ultra-low-sulfur coal and operates two scrubbers at its Sioux energy center. Ameren Missouri does not expect to make additional capital investments to comply with the current CSAPR requirements. However, Ameren Missouri expects to incur additional costs as it lowers its emissions at one or more of its energy centers to comply with the CSAPR in future years. These

higher costs are expected to be collected from customers through the FAC or higher base rates.

In December 2011, the EPA issued the MATS under the Clean Air Act, which requires reductions in emissions of mercury and other hazardous air pollutants, such as acid gases, trace metals, and hydrogen chloride. The MATS do not require a specific control technology to achieve the emission reductions. The MATS apply to each unit at a coal-fired power plant. However, in certain cases, compliance can be achieved by averaging emissions from similar units at the same power plant. Compliance was required by April 2015 or, with a case-by-case extension, by April 2016. All of Ameren Missouri's coal-fired power plants will be in compliance before the required due dates. As part of Ameren Missouri's compliance plan, the Meramec energy center will burn natural gas at two of its units beginning in April 2016, thereby excluding such units from the MATS. In addition, Ameren Missouri is incurring additional costs to comply with the MATS. These higher costs are being collected from customers through the FAC or higher base rates.

CO2 Emissions Standards

The Clean Power Plan, which sets forth CO2 emissions standards applicable to existing power plants, was issued by the EPA but stayed by the United States Supreme Court pending the outcome of various appeals, as discussed below.

If the Clean Power Plan is ultimately upheld as issued, Ameren Missouri expects to incur increased fuel and operating costs, and make new or accelerated capital expenditures, in addition to the costs of making modifications to existing operations in order to achieve compliance. The Clean Power Plan required Missouri and Illinois to reduce CO2 emissions from power plants within their states significantly below 2005 levels by 2030. The rule contains interim compliance periods commencing in 2022 that require each state to demonstrate progress in achieving its CO2 reduction target. Ameren is evaluating the Clean Power Plan's potential impacts to its operations, including those related to electric system reliability, and to its level of investment in customer energy efficiency programs, renewable energy, and other forms of generation investment. Significant uncertainty exists regarding the impact of the Clean Power Plan, as its implementation will depend upon plans to be developed by the states. Numerous legal challenges are pending, which could result in the rule being declared invalid or the nature and timing of CO2 emissions reductions being revised. In February 2016, the United States Supreme Court stayed the Clean Power Plan and all implementation requirements until such time as legal appeals are concluded. The District of Columbia Circuit Court of Appeals has scheduled hearings for June 2016 on the legality of the rule. A decision by the District of Columbia Circuit Court of Appeals is expected to be issued later this year and additional appeals before the United States Supreme Court are likely. Appeals are not expected to conclude prior to 2018. We cannot predict the outcome of such legal challenges or their impact on our results of operations, financial position, or liquidity. If the rule is ultimately upheld and implemented in substantially similar form to the rule when issued, compliance measures could result in the closure or

alteration of the operation of some of Ameren Missouri’s coal and natural-gas-fired energy centers, which could result in increased operating costs. Ameren Missouri expects substantially all of these increased costs to be recoverable, subject to MoPSC prudence review, through higher rates to customers, which could be significant.

Also, in August 2015, the EPA issued final regulations that set CO2 emissions standards for new power plants. These new standards establish separate emissions limits for new natural-gas-fired combined cycle plants and new coal-fired plants.

Federal and state legislation or regulations that mandate limits on the emission of CO2 may result in significant increases in capital expenditures and operating costs, which could lead to increased liquidity needs and higher financing costs. Mandatory limits on the emission of CO2 could increase costs for Ameren Missouri’s customers or have a material adverse effect on Ameren's and Ameren Missouri's results of operations, financial position, and liquidity if regulators delay or deny recovery in rates of these compliance costs. The cost of Ameren Illinois’ purchased power and gas purchased for resale could increase. However, Ameren Illinois expects these costs would be recovered from customers with no material adverse effect on its results of operations, financial position, or liquidity. Ameren's and Ameren Missouri's earnings might benefit from increased investment to comply with CO2 emission limitations to the extent that the investments are reflected and recovered on a timely basis in rates charged to customers.

NSR and Clean Air Litigation

In January 2011, the Department of Justice, on behalf of the EPA, filed a complaint against Ameren Missouri in the United States District Court for the Eastern District of Missouri. The EPA's complaint, as amended in October 2013, alleges that in performing projects at its Rush Island coal-fired energy center in 2007 and 2010, Ameren Missouri violated provisions of the Clean Air Act and Missouri law. Ameren Missouri anticipates that a trial of this case could occur as early as 2016. Ameren Missouri believes its defenses are meritorious and is defending itself vigorously. However, there can be no assurances that it will be successful in its efforts.

The ultimate resolution of this matter could have a material adverse effect on the results of operations, financial position, and liquidity of Ameren and Ameren Missouri. A resolution of this matter could result in increased capital expenditures for the installation of pollution control equipment and increased operations and maintenance expenses. We are unable to predict the ultimate resolution of these matters or the costs that might be incurred.

Clean Water Act

In August 2014, the EPA issued its final rule applicable to cooling water intake structures at existing power plants. The rule requires a case-by-case evaluation and plan for reducing aquatic organisms impinged on the facility’s intake screens or entrained through the plant's cooling water system. All of Ameren

Missouri’s coal-fired and nuclear energy centers are subject to this rule. Each of Ameren Missouri’s affected energy centers will become subject to the revised limitations when it renews its water discharge permit. These permits are scheduled to be renewed between 2018 and 2023. The rule could have an adverse effect on Ameren’s and Ameren Missouri’s results of operations, financial position, and liquidity if its implementation requires the installation of cooling towers or extensive modifications to the cooling water systems at our energy centers and if those investments are not recovered on a timely basis in electric rates charged to Ameren Missouri's customers.

In September 2015, the EPA issued its final rule under the Clean Water Act to revise the effluent limitation guidelines applicable to steam electric generating units. Effluent limitation guidelines are national standards for water discharges that are based on the effectiveness of available control technology. The EPA's rule prohibits effluent discharges of certain, but not all, waste streams and imposes more stringent limitations on certain components in water discharges from power plants. All of Ameren Missouri’s coal-fired energy centers are subject to this rule and its implementation will be consistent with the water discharge permit process described above beginning as early as 2018. Ameren Missouri is evaluating the final rule, which became effective in January 2016, and the possible effects on its operations.

Ash Management

In 2015, the EPA issued regulations regarding the management and disposal of CCR, that will affect future CCR disposal and handling costs at Ameren Missouri's energy centers. The regulations allow for the management of CCR as a solid waste, as well as for its continued beneficial uses, such as recycling, which could reduce the amount to be disposed. The regulations also establish criteria regarding the structural integrity, location, and operation of CCR impoundments and landfills. They require groundwater monitoring and closure of impoundments if the groundwater standards are not achieved. During 2015, Ameren and Ameren Missouri recorded an increase to their AROs associated with CCR storage facilities and accelerated the closure of certain CCR storage facilities at its energy centers as a result of the new regulations. Ameren Missouri plans to close these CCR storage facilities between 2018 and 2023. See Note 1 – Summary of Significant Accounting Policies in this report for additional information. Ameren Missouri's capital expenditure plan includes the cost of constructing landfills as part of its environmental compliance plan.

The new regulations do not apply to ash ponds at plants no longer in operation, such as Ameren’s Meredosia and Hutsonville energy centers.

Remediation

The Ameren Companies are involved in a number of remediation actions to clean up sites affected by hazardous substances, as required by federal and state law. Such laws require that responsible parties fund remediation actions regardless of their degree of fault, the legality of original disposal,

or the ownership of a disposal site. Ameren Missouri and Ameren Illinois have each been identified by federal or state governments as a potentially responsible party at several contaminated sites.

As of December 31, 2015, Ameren Illinois owned or was otherwise responsible for 44 former MGP sites in Illinois, which are in various stages of investigation, evaluation, remediation, and closure. Ameren Illinois estimates it could substantially conclude remediation efforts by 2025. The ICC allows Ameren Illinois to recover remediation and litigation costs associated with its former MGP sites from its electric and natural gas utility customers through environmental adjustment rate riders. Costs are subject to annual prudence review by the ICC. As of December 31, 2015, Ameren Illinois estimated the obligation related to these former MGP sites at $232 million to $313 million. Ameren and Ameren Illinois recorded a liability of $232 million to represent their estimated minimum obligation for these sites, as no other amount within the range was a better estimate.

The scope and extent to which these former MGP sites are remediated may increase as remediation efforts continue. Considerable uncertainty remains in these estimates, as many factors can influence the ultimate actual costs, including site-specific unanticipated underground structures, the degree to which groundwater is encountered, regulatory changes, local ordinances, and site accessibility. The actual costs may vary substantially from these estimates.

Ameren Illinois formerly used an off-site landfill, which Ameren Illinois did not own, in connection with the operation of a previously owned energy center. Ameren Illinois could be required to perform certain maintenance activities at that landfill, which is now closed. As of December 31, 2015, Ameren Illinois estimated the obligation related to this site at $0.5 million to $6 million. Ameren Illinois recorded a liability of $0.5 million to represent its estimated minimum obligation for this site, as no other amount within the range was a better estimate. Ameren Illinois is also responsible for the cleanup of some underground storage tanks and a water treatment plant in Illinois. As of December 31, 2015, Ameren Illinois recorded a liability of $0.7 million to represent its best estimate of the obligation for these sites.

In 2008, the EPA issued an administrative order to Ameren Missouri pertaining to a former coal tar distillery in St. Louis, Missouri, operated by Koppers Company or its predecessor and successor companies. While Ameren Missouri is the current owner of the site, it did not conduct any of the manufacturing operations involving coal tar or its byproducts. Ameren Missouri, along with two other potentially responsible parties, have completed site investigation activities and have submitted their findings to the EPA. As of December 31, 2015, Ameren Missouri estimated its obligation at $2 million to $5 million. Ameren Missouri recorded a liability of $2 million to represent its estimated minimum obligation, as no other amount within the range was a better estimate.

Ameren Missouri also participated in the investigation of several sites located in Sauget, Illinois. In 2000, the EPA notified

Ameren Missouri and numerous other companies, including Solutia, Inc., that former landfills and lagoons at those sites may contain soil and groundwater contamination. These sites are known as Sauget Area 2. From about 1926 until 1976, Ameren Missouri operated an energy center adjacent to Sauget Area 2. Ameren Missouri currently owns a parcel of property at Sauget Area 2 that was once used as a landfill.

In December 2013, the EPA issued its record of decision for Sauget Area 2 approving the investigation and the remediation alternatives recommended by the potentially responsible parties. Further negotiation among the potentially responsible parties will determine how to fund the implementation of the EPA-approved cleanup remedies. As of December 31, 2015, Ameren Missouri estimated its obligation related to Sauget Area 2 at $1 million to $2.5 million. Ameren Missouri recorded a liability of $1 million to represent its estimated minimum obligation, as no other amount within the range was a better estimate.

In December 2012, Ameren Missouri signed an administrative order with the EPA and agreed to investigate soil and groundwater conditions at an Ameren Missouri-owned substation in St. Charles, Missouri. As of December 31, 2015, Ameren Missouri estimated and recorded a $0.6 million liability related to the site. Although monitoring will continue for some time, no significant additional remediation measures are anticipated.

Our operations or those of our predecessor companies involve the use of, disposal of, and in appropriate circumstances, the cleanup of substances regulated under environmental laws. We are unable to determine whether such practices will result in future environmental commitments or will affect our results of operations, financial position, or liquidity.

Pumped-storage Hydroelectric Facility Breach

In December 2005, there was a breach of the upper reservoir at Ameren Missouri's Taum Sauk pumped-storage hydroelectric energy center. The breach resulted in significant flooding in the local area, which damaged a state park. Ameren Missouri had liability insurance coverage for the Taum Sauk incident, subject to certain limits and deductibles.

As of December 31, 2015, Ameren Missouri had an insurance receivable of $41 million. In February 2016, Ameren Missouri and an insurer that was providing Ameren Missouri with liability coverage on the date of the Taum Sauk incident reached a settlement that resulted in Ameren Missouri receiving $42 million. As a result of this settlement, the receivable was included in “Miscellaneous accounts and notes receivable” on Ameren’s and Ameren Missouri’s balance sheets as of December 31, 2015 whereas previously this receivable was included in “Other assets” on their respective balance sheets as of December 31, 2014.

Asbestos-related Litigation

Ameren, Ameren Missouri, and Ameren Illinois have been named, along with numerous other parties, in a number of lawsuits filed by plaintiffs claiming varying degrees of injury from

asbestos exposure at our present or former energy centers. Most have been filed in the Circuit Court of Madison County, Illinois. The total number of defendants named in each case varies, with 75 as the average number of parties as of December 31, 2015. Each lawsuit seeks unspecified damages that, if awarded at trial, typically would be shared among the various defendants.

The following table presents the pending asbestos-related lawsuits filed against Ameren Missouri and Ameren Illinois as of December 31, 2015:

Ameren Missouri		Ameren Illinois		Total(a)
26		38		48

(a)	Total does not equal the sum of the subsidiary unit lawsuits because some of the lawsuits name multiple Ameren entities as defendants.

At December 31, 2015, Ameren, Ameren Missouri, and Ameren Illinois had liabilities of $8 million, $3 million, and $5 million, respectively, recorded to represent their best estimates of their obligations related to asbestos claims.

Ameren Illinois has a tariff rider to recover the costs of IP asbestos-related litigation claims, subject to the following terms: 90% of the cash expenditures in excess of the amount included in base electric rates is to be recovered from a trust fund that was established when Ameren acquired IP. At December 31, 2015, the trust fund balance was $22 million, including accumulated interest. If cash expenditures are less than the amount in base rates, Ameren Illinois will contribute 90% of the difference to the trust fund. Once the trust fund is depleted, 90% of allowed cash expenditures in excess of base rates will be recovered through charges assessed to customers under the tariff rider. The rider will permit recovery from electric customers within IP’s historical service territory.

Ameren Missouri Municipal Taxes

The cities of Creve Coeur and Winchester, Missouri, on behalf of themselves and other municipalities in Ameren Missouri’s service area, filed a class action lawsuit in November 2011 against Ameren Missouri in the Circuit Court of St. Louis

County, Missouri. The lawsuit alleges that Ameren Missouri failed to collect and pay gross receipts taxes or license fees on certain revenues. Ameren and Ameren Missouri recorded immaterial liabilities on their respective balance sheets as of December 31, 2015, representing their estimate of taxes and fees due as a result of this lawsuit. The ultimate resolution of any unpaid municipal tax or fees could have a material adverse effect on the results of operations, financial position, and liquidity of Ameren and Ameren Missouri. Ameren Missouri believes its defenses are meritorious and is defending itself vigorously; however, there can be no assurances that Ameren Missouri will be successful in its efforts.

NOTE 16 – DIVESTITURE TRANSACTIONS AND DISCONTINUED OPERATIONS

On December 2, 2013, Ameren completed the divestiture of New AER to IPH in accordance with the transaction agreement between Ameren and IPH dated March 14, 2013, as amended by a letter agreement dated December 2, 2013. Pursuant to that agreement, in 2015, Ameren paid $25 million related to a previously-recorded liability and concluded its obligations to provide credit support to New AER with no resulting additional impact to its results of operations. The transaction agreement with IPH, as amended, provides that if the Elgin, Gibson City, and Grand Tower gas-fired energy centers are subsequently sold by Medina Valley and if Medina Valley receives additional proceeds from such sale, Medina Valley will pay Genco any proceeds from such sale, net of taxes and other expenses, in excess of the $137.5 million previously paid to Genco.

On January 31, 2014, Medina Valley completed the sale of the Elgin, Gibson City, and Grand Tower gas-fired energy centers to Rockland Capital for a total purchase price of $168 million. The agreement with Rockland Capital required a portion of the purchase price to be held in escrow until January 31, 2016, to fund certain indemnity obligations, if any, of Medina Valley. Medina Valley received the escrow balance from Rockland Capital and expects to pay Genco its portion of that escrow balance during the first quarter of 2016.

Discontinued Operations Presentation

All matters related to the final tax basis of New AER and the related tax benefit resulting from the divested merchant generation business have been resolved with the completion of the IRS audit for 2013. During 2015, based on the completion of the IRS audit, Ameren removed a reserve for unrecognized tax benefits recorded in 2013 and recognized a tax benefit from discontinued operations. See Note 13 – Income Taxes for additional information regarding the Ameren Companies’ uncertain tax positions.

The following table presents the components of discontinued operations in Ameren's consolidated statement of income (loss) for the years ended December 31, 2015, 2014, and 2013:

	Year ended
	2015				2014				2013
Operating revenues	$	—			$	1			$	1,037
Operating benefits (expenses)	1				(2		)		(1,207		)	(a)
Operating income (loss)	1				(1		)		(170		)
Other income (loss)	—				—				(1		)
Interest charges	—				—				(39		)
Income (loss) before income taxes	1				(1		)		(210		)
Income tax (expense) benefit	50				—				(13		)
Income (loss) from discontinued operations, net of taxes	$	51			$	(1	)		$	(223	)

(a)	Includes a $201 million pretax loss on disposal relating to the New AER divestiture.

The following table presents the carrying amounts of the components of assets and liabilities of Ameren's discontinued operations, which consist primarily of AROs and related deferred income tax assets associated with the abandoned Meredosia and Hutsonville energy centers, at December 31, 2015 and 2014:

	December 31, 2015				December 31, 2014
Assets of discontinued operations
Accumulated deferred income taxes, net	$	14			$	15
Total assets of discontinued operations	$	14			$	15
Liabilities of discontinued operations
Accounts payable and other current obligations	$	1			$	1
Asset retirement obligations(a)	28				32
Total liabilities of discontinued operations	$	29			$	33

(a)	Ameren is demolishing the Hutsonville energy center and expects to demolish the Meredosia energy center beginning in 2016.

NOTE 17 – SEGMENT INFORMATION

Ameren has two reportable segments: Ameren Missouri and Ameren Illinois. Ameren Missouri and Ameren Illinois each have one reportable segment. The Ameren Missouri segment for both Ameren and Ameren Missouri includes all the operations of Ameren Missouri as described in Note 1 – Summary of Significant Accounting Policies. The Ameren Illinois segment for

both Ameren and Ameren Illinois consists of all of the operations of Ameren Illinois as described in Note 1 – Summary of Significant Accounting Policies. The category called Other primarily includes Ameren parent company activities, Ameren Services, and ATXI. The Other category also includes certain corporate activities previously included in the Merchant Generation segment. See Note 16 – Divestiture Transactions and Discontinued Operations for additional information.

The following table presents information about the reported revenues and specified items reflected in Ameren’s net income attributable to Ameren common shareholders and capital expenditures from continuing operations for the years ended December 31, 2015, 2014, and 2013, and total assets in continuing operations as of December 31, 2015, 2014, and 2013:

	Ameren Missouri				Ameren Illinois				Other				Intersegment Eliminations				Consolidated
2015
External revenues	$	3,566			$	2,462			$	70			$	—			$	6,098
Intersegment revenues	43				4				2				(49		)		—
Depreciation and amortization	492				295				9				—				796
Interest and dividend income	28				12				1				—				41
Interest charges	219				131				5				—				355
Income taxes	209				127				27				—				363
Net income attributable to Ameren common shareholders from continuing operations	352				214				13				—				579
Capital expenditures	622				918				377			(a)	—				1,917
Total assets(c)	13,851				8,903				1,139				(267		)		23,626			(b)
2014
External revenues	$	3,526			$	2,496			$	31			$	—			$	6,053
Intersegment revenues	27				2				2				(31		)		—
Depreciation and amortization	473				263				9				—				745
Interest and dividend income	28				7				2				—				37
Interest charges	211				112				18				—				341
Income taxes	229				143				5				—				377
Net income (loss) attributable to Ameren common shareholders from continuing operations	390				201				(4		)		—				587
Capital expenditures	747				835				203			(a)	—				1,785
Total assets(c)	13,474				8,204				799				(203		)		22,274			(b)
2013
External revenues	$	3,516			$	2,307			$	15			$	—			$	5,838
Intersegment revenues	25				4				2				(31		)		—
Depreciation and amortization	454				243				9				—				706
Interest and dividend income	27				2				1				—				30
Interest charges	210				143				45				—				398
Income taxes (benefit)	242				110				(41		)		—				311
Net income (loss) attributable to Ameren common shareholders from continuing operations	395				160				(43		)		—				512
Capital expenditures	648				701				30			(a)	—				1,379
Total assets(c)	12,867				7,397				711				(233		)		20,742			(b)

(a)	Includes the elimination of intercompany transfers.

(b)	Excludes total assets from discontinued operations of $14 million, $15 million, and $165 million as of December 31, 2015, 2014, and 2013, respectively.

(c)	Reflects the adoption of the new authoritative accounting guidance for the presentation of debt issuance costs and balance sheet classification of deferred income taxes. See Note 1 – Summary of Significant Accounting Policies for additional information.

SELECTED QUARTERLY INFORMATION (Unaudited) (In millions, except per share amounts)

Ameren	2015																	2014
Quarter ended(a)	March 31				June 30				September 30				December 31					March 31				June 30				September 30				December 31
Operating revenues	$	1,556			$	1,401			$	1,833			$	1,308				$	1,594			$	1,419			$	1,670			$	1,370
Operating income	256				237				626				140					246				322				561				125
Net income	110				151				345				30					98				150				295				49
Net income attributable to Ameren common shareholders – continuing operations	$	108			$	98			$	343			$	30				$	97			$	150			$	294			$	46
Net income (loss) attributable to Ameren common shareholders – discontinued operations	—				52				—				(1		)			(1		)		(1		)		(1		)		2
Net income attributable to Ameren common shareholders	$	108			$	150			$	343			$	29				$	96			$	149			$	293			$	48
Earnings per common share – basic – continuing operations	$	0.45			$	0.40			$	1.42			$	0.12				$	0.40			$	0.62			$	1.21			$	0.19
Earnings (loss) per common share – basic – discontinued operations	—				0.21				—				—					—				(0.01		)		—				0.01
Earnings per common share – basic	$	0.45			$	0.61			$	1.42			$	0.12				$	0.40			$	0.61			$	1.21			$	0.20
Earnings per common share – diluted – continuing operations	$	0.45			$	0.40			$	1.41			$	0.12				$	0.40			$	0.62			$	1.20			$	0.19
Earnings (loss) per common share – diluted – discontinued operations	—				0.21				—				—					—				(0.01		)		—				0.01
Earnings per common share – diluted	$	0.45			$	0.61			$	1.41			$	0.12				$	0.40			$	0.61			$	1.20			$	0.20

(a)	The sum of quarterly amounts, including per share amounts, may not equal amounts reported for year-to-date periods. This is because of the effects of rounding and the changes in the number of weighted-average diluted shares outstanding each period.

Ameren Missouri Quarter ended		Operating Revenues				Operating Income				Net Income (Loss)				Net Income (Loss) Available to Common Shareholder
March 31, 2015		$	800			$	115			$	42			$	41
March 31, 2014		817				119				48				47
June 30, 2015		884				146				62				61
June 30, 2014		900				243				127				126
September 30, 2015		1,171				423				240				239
September 30, 2014		1,097				394				223				222
December 31, 2015		754				58				11				11
December 31, 2014		739				29				(5		)		(5		)

Ameren Illinois Quarter ended		Operating Revenues				Operating Income				Net Income				Net Income Available to Common Shareholder
March 31, 2015		$	745			$	120			$	54			$	53
March 31, 2014		774				120				54				53
June 30, 2015		513				83				32				31
June 30, 2014		519				75				29				28
September 30, 2015		655				189				98				98
September 30, 2014		572				158				75				75
December 31, 2015		553				74				33				32
December 31, 2014		633				97				46				45