Item 8. FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA

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Item 8. FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA

Report of Independent Registered Public Accounting Firm

To the Board of Directors and Shareholders

of Ameren Corporation:

Opinions on the Financial Statements and Internal Control over Financial Reporting

We have audited the accompanying consolidated balance sheets of Ameren Corporation and its subsidiaries (the “Company”) as of December 31, 2018 and 2017, and the related consolidated statements of income and comprehensive income, of shareholders’ equity and of cash flows for each of the three years in the period ended December 31, 2018, including the related notes and financial statement schedules listed in the index appearing under Item 15(a)(2) (collectively referred to as the “consolidated financial statements”). We also have audited the Company’s internal control over financial reporting as of December 31, 2018, based on criteria established in Internal Control - Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission (COSO).

In our opinion, the consolidated financial statements referred to above present fairly, in all material respects, the financial position of the Company as of December 31, 2018 and 2017, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2018, in conformity with accounting principles generally accepted in the United States of America. Also in our opinion, the Company maintained, in all material respects, effective internal control over financial reporting as of December 31, 2018, based on criteria established in Internal Control - Integrated Framework (2013) issued by the COSO.

Basis for Opinions

The Company’s management is responsible for these consolidated financial statements, 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 the Company’s consolidated financial statements and on the Company’s internal control over financial reporting based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (“PCAOB”) and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audits to obtain reasonable assurance about whether the consolidated financial statements are free of material misstatement, whether due to error or fraud, and whether effective internal control over financial reporting was maintained in all material respects.

Our audits of the consolidated financial statements included performing procedures to assess the risks of material misstatement of the consolidated financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the consolidated financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the consolidated financial statements. 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.

Definition and Limitations of Internal Control over Financial Reporting

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

St. Louis, Missouri

February 26, 2019

We have served as the Company’s auditor since at least 1932. We have not been able to determine the specific year we began serving as auditor of the Company.

Report of Independent Registered Public Accounting Firm

To the Board of Directors and Shareholders

of Union Electric Company:

Opinion on the Financial Statements

We have audited the accompanying balance sheets of Union Electric Company (the “Company”) as of December 31, 2018 and 2017, and the related statements of income, of shareholders’ equity and of cash flows for each of the three years in the period ended December 31, 2018, including the related notes and financial statement schedule listed in the index appearing under Item 15(a)(2) (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2018 and 2017, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2018, in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinion

These financial statements are the responsibility of the Company’s management. Our responsibility is to express an opinion on the Company’s financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (“PCAOB”) and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits of these financial statements in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud. The Company is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting. As part of our audits we are required to obtain an understanding of internal control over financial reporting but not for the purpose of expressing an opinion on the effectiveness of the Company’s internal control over financial reporting. Accordingly, we express no such opinion.

Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. We believe that our audits provide a reasonable basis for our opinion.

/s/ PricewaterhouseCoopers LLP

St. Louis, Missouri

February 26, 2019

We have served as the Company’s auditor since at least 1932. We have not been able to determine the specific year we began serving as auditor of the Company.

Report of Independent Registered Public Accounting Firm

To the Board of Directors and Shareholders

of Ameren Illinois Company:

Opinion on the Financial Statements

We have audited the accompanying balance sheets of Ameren Illinois Company (the “Company”) as of December 31, 2018 and 2017, and the related statements of income and comprehensive income, of shareholders’ equity and of cash flows for each of the three years in the period ended December 31, 2018, including the related notes and financial statement schedule listed in the index appearing under Item 15(a)(2) (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2018 and 2017, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2018, in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinion

/s/ PricewaterhouseCoopers LLP

St. Louis, Missouri

February 26, 2019

We have served as the Company’s auditor since 1998.

AMEREN CORPORATION CONSOLIDATED STATEMENT OF INCOME AND COMPREHENSIVE INCOME (In millions, except per share amounts)

	Year Ended December 31,
	2018			2017		2016
Operating Revenues:
Electric	$	5,339		$	5,307	$	5,196
Natural gas	952			867		880
Total operating revenues	6,291			6,174		6,076
Operating Expenses:
Fuel	769			737		745
Purchased power	581			638		623
Natural gas purchased for resale	374			311		341
Other operations and maintenance	1,772			1,705		1,733
Depreciation and amortization	955			896		845
Taxes other than income taxes	483			477		467
Total operating expenses	4,934			4,764		4,754
Operating Income	1,357			1,410		1,322
Other Income, Net	102			86		101
Interest Charges	401			391		382
Income Before Income Taxes	1,058			1,105		1,041
Income Taxes	237			576		382
Net Income	821			529		659
Less: Net Income Attributable to Noncontrolling Interests	6			6		6
Net Income Attributable to Ameren Common Shareholders	$	815		$	523	$	653


Net Income	$	821		$	529	$	659
Other Comprehensive Income (Loss), Net of Taxes
Pension and other postretirement benefit plan activity, net of income taxes (benefit) of $(1), $3, and $(7), respectively	(4		)	5		(20		)
Comprehensive Income	817			534		639
Less: Comprehensive Income Attributable to Noncontrolling Interests	6			6		6
Comprehensive Income Attributable to Ameren Common Shareholders	$	811		$	528	$	633


Earnings per Common Share – Basic	$	3.34		$	2.16	$	2.69

Earnings per Common Share – Diluted	$	3.32		$	2.14	$	2.68

Weighted-average Common Shares Outstanding – Basic	243.8			242.6		242.6
Weighted-average Common Shares Outstanding – Diluted	245.8			244.2		243.4

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,
	2018			2017
ASSETS
Current Assets:
Cash and cash equivalents	$	16		$	10
Accounts receivable – trade (less allowance for doubtful accounts of $18 and $19, respectively)	463			445
Unbilled revenue	295			323
Miscellaneous accounts receivable	79			70
Inventories	483			522
Current regulatory assets	134			144
Other current assets	63			98
Total current assets	1,533			1,612
Property, Plant, and Equipment, Net	22,810			21,466
Investments and Other Assets:
Nuclear decommissioning trust fund	684			704
Goodwill	411			411
Regulatory assets	1,127			1,230
Other assets	650			522
Total investments and other assets	2,872			2,867
TOTAL ASSETS	$	27,215		$	25,945
LIABILITIES AND EQUITY
Current Liabilities:
Current maturities of long-term debt	$	580		$	841
Short-term debt	597			484
Accounts and wages payable	817			902
Taxes accrued	53			52
Interest accrued	93			99
Customer deposits	116			108
Current regulatory liabilities	149			128
Other current liabilities	282			326
Total current liabilities	2,687			2,940
Long-term Debt, Net	7,859			7,094
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes, net	2,623			2,506
Accumulated deferred investment tax credits	43			49
Regulatory liabilities	4,637			4,387
Asset retirement obligations	627			638
Pension and other postretirement benefits	558			545
Other deferred credits and liabilities	408			460
Total deferred credits and other liabilities	8,896			8,585
Commitments and Contingencies (Notes 2, 9, and 14)
Ameren Corporation Shareholders’ Equity:
Common stock, $.01 par value, 400.0 shares authorized – shares outstanding of 244.5 and 242.6, respectively	2			2
Other paid-in capital, principally premium on common stock	5,627			5,540
Retained earnings	2,024			1,660
Accumulated other comprehensive loss	(22		)	(18		)
Total Ameren Corporation shareholders’ equity	7,631			7,184
Noncontrolling Interests	142			142
Total equity	7,773			7,326
TOTAL LIABILITIES AND EQUITY	$	27,215		$	25,945

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,
	2018			2017			2016
Cash Flows From Operating Activities:
Net income	$	821		$	529		$	659
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	938			876			835
Amortization of nuclear fuel	95			76			88
Amortization of debt issuance costs and premium/discounts	20			22			22
Deferred income taxes and investment tax credits, net	224			539			386
Allowance for equity funds used during construction	(36		)	(24		)	(27		)
Stock-based compensation costs	20			17			17
Other	44			(10		)	4
Changes in assets and liabilities:
Receivables	(24		)	(53		)	(71		)
Inventories	39			17			11
Accounts and wages payable	(22		)	32			19
Taxes accrued	(10		)	55			13
Regulatory assets and liabilities	201			36			215
Assets, other	2			34			(21		)
Liabilities, other	(117		)	(7		)	(17		)
Pension and other postretirement benefits	(25		)	(21		)	(16		)
Net cash provided by operating activities	2,170			2,118			2,117
Cash Flows From Investing Activities:
Capital expenditures	(2,286		)	(2,132		)	(2,076		)
Nuclear fuel expenditures	(52		)	(63		)	(55		)
Purchases of securities – nuclear decommissioning trust fund	(315		)	(321		)	(322		)
Sales and maturities of securities – nuclear decommissioning trust fund	299			305			304
Other	18			7			(9		)
Net cash used in investing activities	(2,336		)	(2,204		)	(2,158		)
Cash Flows From Financing Activities:
Dividends on common stock	(451		)	(431		)	(416		)
Dividends paid to noncontrolling interest holders	(6		)	(6		)	(6		)
Short-term debt, net	112			(74		)	257
Maturities of long-term debt	(841		)	(681		)	(395		)
Issuances of long-term debt	1,352			1,345			396
Issuances of common stock	74			—			—
Debt issuance costs	(14		)	(11		)	(9		)
Repurchases of common stock for stock-based compensation	—			(24		)	(51		)
Employee payroll taxes related to stock-based compensation	(19		)	(15		)	(32		)
Other	(2		)	(1		)	(2		)
Net cash provided by (used in) financing activities	205			102			(258		)
Net change in cash, cash equivalents, and restricted cash	39			16			(299		)
Cash, cash equivalents, and restricted cash at beginning of year	68			52			351
Cash, cash equivalents, and restricted cash at end of year	$	107		$	68		$	52

Noncash financing activity – Issuance of common stock for stock-based compensation	$	35		$	—		$	—

Cash Paid (Refunded) During the Year:
Interest (net of $21, $14, and $15 capitalized, respectively)	$	387		$	370		$	358
Income taxes, net	21			(19		)	(12		)

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

AMEREN CORPORATION CONSOLIDATED STATEMENT OF SHAREHOLDERS’ EQUITY (In millions)

	December 31,
	2018			2017			2016
Common Stock	$	2		$	2		$	2

Other Paid-in Capital:
Beginning of year	5,540			5,556			5,616
Shares issued under the DRPlus and 401(k) plan	74			—			—
Stock-based compensation activity	13			(16		)	(60		)
Other paid-in capital, end of year	5,627			5,540			5,556
Retained Earnings:
Beginning of year	1,660			1,568			1,331
Net income attributable to Ameren common shareholders	815			523			653
Dividends	(451		)	(431		)	(416		)
Retained earnings, end of year	2,024			1,660			1,568
Accumulated Other Comprehensive Income (Loss):
Deferred retirement benefit costs, beginning of year	(18		)	(23		)	(3		)
Change in deferred retirement benefit costs	(4		)	5			(20		)
Deferred retirement benefit costs, end of year	(22		)	(18		)	(23		)
Total accumulated other comprehensive loss, end of year	(22		)	(18		)	(23		)
Total Ameren Corporation Shareholders’ Equity	$	7,631		$	7,184		$	7,103

Noncontrolling Interests:
Beginning of year	142			142			142
Net income attributable to noncontrolling interest holders	6			6			6
Dividends paid to noncontrolling interest holders	(6		)	(6		)	(6		)
Noncontrolling interests, end of year	142			142			142
Total Equity	$	7,773		$	7,326		$	7,245


Common stock shares outstanding at beginning of year	242.6			242.6			242.6
Shares issued under the DRPlus and 401(k) plan	1.2			—			—
Shares issued for stock-based compensation	0.7			—			—
Common stock shares outstanding at end of year	244.5			242.6			242.6

Dividends per common share	$	1.8475		$	1.7775		$	1.7150

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

UNION ELECTRIC COMPANY (d/b/a AMEREN MISSOURI) STATEMENT OF INCOME (In millions)

	Year Ended December 31,
	2018		2017		2016
Operating Revenues:
Electric	$	3,451	$	3,411	$	3,396
Natural gas	138		126		128
Total operating revenues	3,589		3,537		3,524
Operating Expenses:
Fuel	769		737		745
Purchased power	164		245		254
Natural gas purchased for resale	56		47		49
Other operations and maintenance	972		925		912
Depreciation and amortization	550		533		514
Taxes other than income taxes	329		328		325
Total operating expenses	2,840		2,815		2,799
Operating Income	749		722		725
Other Income, Net	56		65		62
Interest Charges	200		207		211
Income Before Income Taxes	605		580		576
Income Taxes	124		254		216
Net Income	$	481	$	326	$	360
Preferred Stock Dividends	3		3		3
Net Income Available to Common Shareholder	$	478	$	323	$	357

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,
	2018		2017
ASSETS
Current Assets:
Cash and cash equivalents	$	—	$	—
Accounts receivable – trade (less allowance for doubtful accounts of $7 and $7, respectively)	223		200
Accounts receivable – affiliates	14		11
Unbilled revenue	155		165
Miscellaneous accounts receivable	42		35
Inventories	358		388
Current regulatory assets	14		56
Other current assets	26		50
Total current assets	832		905
Property, Plant, and Equipment, Net	12,103		11,751
Investments and Other Assets:
Nuclear decommissioning trust fund	684		704
Regulatory assets	366		395
Other assets	306		288
Total investments and other assets	1,356		1,387
TOTAL ASSETS	$	14,291	$	14,043
LIABILITIES AND SHAREHOLDERS’ EQUITY
Current Liabilities:
Current maturities of long-term debt	$	580	$	384
Short-term debt	55		39
Accounts and wages payable	428		475
Accounts payable – affiliates	69		60
Taxes accrued	27		30
Interest accrued	52		54
Current regulatory liabilities	68		19
Other current liabilities	123		103
Total current liabilities	1,402		1,164
Long-term Debt, Net	3,418		3,577
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes, net	1,534		1,650
Accumulated deferred investment tax credits	42		48
Regulatory liabilities	2,799		2,664
Asset retirement obligations	623		634
Pension and other postretirement benefits	228		213
Other deferred credits and liabilities	16		12
Total deferred credits and other liabilities	5,242		5,221
Commitments and Contingencies (Notes 2, 9, 13, and 14)
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	1,903		1,858
Preferred stock	80		80
Retained earnings	1,735		1,632
Total shareholders’ equity	4,229		4,081
TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY	$	14,291	$	14,043

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,
	2018			2017			2016
Cash Flows From Operating Activities:
Net income	$	481		$	326		$	360
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	533			514			506
Amortization of nuclear fuel	95			76			88
Amortization of debt issuance costs and premium/discounts	6			6			6
Deferred income taxes and investment tax credits, net	(9		)	82			179
Allowance for equity funds used during construction	(27		)	(21		)	(23		)
Other	17			4			5
Changes in assets and liabilities:
Receivables	(32		)	(46		)	5
Inventories	30			18			(4		)
Accounts and wages payable	(21		)	27			(18		)
Taxes accrued	(1		)	(1		)	11
Regulatory assets and liabilities	201			26			84
Assets, other	2			31			(25		)
Liabilities, other	(13		)	(23		)	(1		)
Pension and other postretirement benefits	(2		)	(2		)	(4		)
Net cash provided by operating activities	1,260			1,017			1,169
Cash Flows From Investing Activities:
Capital expenditures	(914		)	(773		)	(738		)
Nuclear fuel expenditures	(52		)	(63		)	(55		)
Purchases of securities – nuclear decommissioning trust fund	(315		)	(321		)	(322		)
Sales and maturities of securities – nuclear decommissioning trust fund	299			305			304
Money pool advances, net	—			161			(125		)
Other	6			7			(1		)
Net cash used in investing activities	(976		)	(684		)	(937		)
Cash Flows From Financing Activities:
Dividends on common stock	(375		)	(362		)	(355		)
Dividends on preferred stock	(3		)	(3		)	(3		)
Short-term debt, net	16			39			—
Maturities of long-term debt	(384		)	(431		)	(266		)
Issuances of long-term debt	423			399			149
Debt issuance costs	(5		)	(3		)	(3		)
Capital contribution from parent	45			30			44
Net cash used in financing activities	(283		)	(331		)	(434		)
Net change in cash, cash equivalents, and restricted cash	1			2			(202		)
Cash, cash equivalents, and restricted cash at beginning of year	7			5			207
Cash, cash equivalents, and restricted cash at end of year	$	8		$	7		$	5

Cash Paid During the Year:
Interest (net of $14, $10, and $12 capitalized, respectively)	$	196		$	202		$	209
Income taxes, net	128			178			27

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,
	2018			2017			2016
Common Stock	$	511		$	511		$	511

Other Paid-in Capital:
Beginning of year	1,858			1,828			1,822
Capital contribution from parent	45			30			6
Other paid-in capital, end of year	1,903			1,858			1,828

Preferred Stock	80			80			80

Retained Earnings:
Beginning of year	1,632			1,671			1,669
Net income	481			326			360
Common stock dividends	(375		)	(362		)	(355		)
Preferred stock dividends	(3		)	(3		)	(3		)
Retained earnings, end of year	1,735			1,632			1,671

Total Shareholders’ Equity	$	4,229		$	4,081		$	4,090

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,
	2018		2017		2016
Operating Revenues:
Electric	$	1,761	$	1,784	$	1,735
Natural gas	815		743		754
Total operating revenues	2,576		2,527		2,489
Operating Expenses:
Purchased power	429		417		399
Natural gas purchased for resale	318		264		292
Other operations and maintenance	799		799		828
Depreciation and amortization	374		341		319
Taxes other than income taxes	144		137		132
Total operating expenses	2,064		1,958		1,970
Operating Income	512		569		519
Other Income, Net	42		12		34
Interest Charges	149		144		140
Income Before Income Taxes	405		437		413
Income Taxes	98		166		158
Net Income	307		271		255
Other Comprehensive Loss, Net of Taxes:
Pension and other postretirement benefit plan activity, net of income tax benefit of $-, $-, and $(1), respectively	—		—		(5		)
Comprehensive Income	$	307	$	271	$	250


Net Income	$	307	$	271	$	255
Preferred Stock Dividends	3		3		3
Net Income Available to Common Shareholder	$	304	$	268	$	252

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,
	2018		2017
ASSETS
Current Assets:
Cash and cash equivalents	$	—	$	—
Accounts receivable – trade (less allowance for doubtful accounts of $11 and $12, respectively)	224		234
Accounts receivable – affiliates	21		9
Unbilled revenue	140		158
Miscellaneous accounts receivable	40		35
Inventories	125		134
Current regulatory assets	110		87
Other current assets	16		15
Total current assets	676		672
Property, Plant, and Equipment, Net	9,198		8,293
Investments and Other Assets:
Goodwill	411		411
Regulatory assets	759		822
Other assets	275		147
Total investments and other assets	1,445		1,380
TOTAL ASSETS	$	11,319	$	10,345
LIABILITIES AND SHAREHOLDERS’ EQUITY
Current Liabilities:
Current maturities of long-term debt	$	—	$	457
Short-term debt	72		62
Accounts and wages payable	302		337
Accounts payable – affiliates	58		70
Taxes accrued	23		19
Interest accrued	31		33
Customer deposits	76		69
Current environmental remediation	42		42
Current regulatory liabilities	62		92
Other current liabilities	130		177
Total current liabilities	796		1,358
Long-term Debt, Net	3,296		2,373
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes, net	1,119		1,021
Regulatory liabilities	1,741		1,629
Pension and other postretirement benefits	280		285
Environmental remediation	109		134
Other deferred credits and liabilities	204		235
Total deferred credits and other liabilities	3,453		3,304
Commitments and Contingencies (Notes 2, 13, and 14)
Shareholders’ Equity:
Common stock, no par value, 45.0 shares authorized – 25.5 shares outstanding	—		—
Other paid-in capital	2,173		2,013
Preferred stock	62		62
Retained earnings	1,539		1,235
Total shareholders’ equity	3,774		3,310
TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY	$	11,319	$	10,345

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,
	2018			2017			2016
Cash Flows From Operating Activities:
Net income	$	307		$	271		$	255
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	375			341			318
Amortization of debt issuance costs and premium/discounts	13			13			14
Deferred income taxes and investment tax credits, net	88			171			154
Other	11			—			(1		)
Changes in assets and liabilities:
Receivables	—			(7		)	(72		)
Inventories	8			(1		)	15
Accounts and wages payable	(13		)	19			12
Taxes accrued	(13		)	18			1
Regulatory assets and liabilities	1			16			120
Assets, other	(1		)	(2		)	(3		)
Liabilities, other	(92		)	3			(9		)
Pension and other postretirement benefits	(25		)	(14		)	(8		)
Net cash provided by operating activities	659			828			796
Cash Flows From Investing Activities:
Capital expenditures	(1,258		)	(1,076		)	(924		)
Other	10			6			6
Net cash used in investing activities	(1,248		)	(1,070		)	(918		)
Cash Flows From Financing Activities:
Dividends on common stock	—			—			(110		)
Dividends on preferred stock	(3		)	(3		)	(3		)
Short-term debt, net	10			11			51
Maturities of long-term debt	(457		)	(250		)	(129		)
Issuances of long-term debt	929			496			247
Debt issuance costs	(9		)	(6		)	(4		)
Capital contribution from parent	160			8			—
Other	(2		)	(1		)	(1		)
Net cash provided by financing activities	628			255			51
Net change in cash and cash equivalents	39			13			(71		)
Cash, cash equivalents, and restricted cash at beginning of year	41			28			99
Cash, cash equivalents, and restricted cash at end of year	$	80		$	41		$	28

Cash Paid (Refunded) During the Year:
Interest (net of $7, $4, and $3 capitalized, respectively)	$	144		$	139		$	127
Income taxes, net	28			(22		)	8

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,
	2018			2017			2016
Common Stock	$	—		$	—		$	—

Other Paid-in Capital
Beginning of year	2,013			2,005			2,005
Capital contribution from parent	160			8			—
Other paid-in capital, end of year	2,173			2,013			2,005

Preferred Stock	62			62			62

Retained Earnings:
Beginning of year	1,235			967			825
Net income	307			271			255
Common stock dividends	—			—			(110		)
Preferred stock dividends	(3		)	(3		)	(3		)
Retained earnings, end of year	1,539			1,235			967

Accumulated Other Comprehensive Income:
Deferred retirement benefit costs, beginning of year	—			—			5
Change in deferred retirement benefit costs	—			—			(5		)
Deferred retirement benefit costs, end of year	—			—			—
Total accumulated other comprehensive income, end of year	—			—			—

Total Shareholders’ Equity	$	3,774		$	3,310		$	3,034

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, 2018

NOTE 1 – SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

General

Ameren, headquartered in St. Louis, Missouri, is a public utility holding company whose primary assets are its equity interests in its subsidiaries. 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. Ameren also has other subsidiaries that conduct other activities, such as providing shared services.


•	Union Electric Company, doing business as Ameren Missouri, operates a rate-regulated electric generation, transmission, and distribution business and a rate-regulated natural gas 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, which 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.

•

Union Electric Company, doing business as Ameren Missouri, operates a rate-regulated electric generation, transmission, and distribution business and a rate-regulated natural gas 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, which 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 transmission, electric distribution, and natural gas distribution businesses in Illinois. Ameren Illinois was incorporated in Illinois in 1923 and is 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 a 40,000 square mile area in central and southern Illinois. Ameren Illinois supplies electric service to 1.2 million customers and natural gas service to 0.8 million customers.

•

Ameren Illinois Company, doing business as Ameren Illinois, operates rate-regulated electric transmission, electric distribution, and natural gas distribution businesses in Illinois. Ameren Illinois was incorporated in Illinois in 1923 and is 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 a 40,000 square mile area in central and southern Illinois. Ameren Illinois supplies electric service to 1.2 million customers and natural gas service to 0.8 million customers.


•	Ameren Transmission Company of Illinois, doing business as ATXI, operates a FERC rate-regulated electric transmission business. ATXI was incorporated in Illinois in 2006. ATXI is constructing MISO-approved electric transmission projects, including the Illinois Rivers and Mark Twain projects, and operates the Spoon River project, which was placed in service in February 2018. Ameren also evaluates competitive electric transmission investment opportunities as they arise.

•

Ameren Transmission Company of Illinois, doing business as ATXI, operates a FERC rate-regulated electric transmission business. ATXI was incorporated in Illinois in 2006. ATXI is constructing MISO-approved electric transmission projects, including the Illinois Rivers and Mark Twain projects, and operates the Spoon River project, which was placed in service in February 2018. Ameren also evaluates competitive electric transmission investment opportunities as they arise.

Ameren’s financial statements are prepared on a consolidated basis and therefore include the accounts of its majority-owned subsidiaries. All intercompany transactions have been eliminated. Ameren Missouri and Ameren Illinois have no subsidiaries. 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. 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 regulatory rate review.

In Ameren Missouri’s and Ameren Illinois’ natural gas businesses, changes in natural gas costs are reflected in billings to their respective 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 customers in a subsequent period.

Ameren Missouri has a FAC that allows an adjustment of electric rates three times per year, without a traditional rate proceeding, for a pass-through to customers of 95% of the variance in net energy costs from 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 customers in a subsequent period.

In Ameren Illinois’ electric distribution business, changes in purchased power and transmission service costs are reflected in billings to its 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 customers in a subsequent period.

In addition to the rate-adjustment mechanisms discussed above, 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 position tracker, a tracker on certain excess deferred taxes, a renewable energy standards cost tracker, a solar rebate program tracker, PISA, and a RESRAM. Ameren Illinois’ and ATXI’s electric transmission rates are determined pursuant to formula ratemaking. Ameren Illinois participates in performance-based formula ratemaking for its electric distribution business and its electric energy-efficiency investments. Ameren Illinois also has environmental cost riders, an asbestos-related litigation rider, a natural gas energy-efficiency rider, a QIP rider, a VBA rider, a bad debt rider, and cost recovery mechanisms for renewable energy credits and zero emission credits. See Note 2 – Rate and Regulatory Matters for additional information on the regulatory assets and liabilities recorded at December 31, 2018 and 2017.

Ameren, Ameren Missouri, and Ameren Illinois continually assess the recoverability of their regulatory assets. 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 reductions in customers rates or refunds to customers related to regulatory liabilities are no longer probable, the amounts are credited to earnings.

Cash, Cash Equivalents, and Restricted Cash

Cash and cash equivalents include short-term, highly liquid investments purchased with an original maturity of three months or less. Cash and cash equivalents subject to legal or contractual restrictions and not readily available for use for general corporate purposes are classified as restricted cash.

In November 2016, the FASB issued authoritative guidance that requires, including on a retrospective basis, restricted cash to be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. Our adoption of this guidance, effective January 2018, did not result in material changes to previously reported cash flows from operating, investing, or financing activities. The changes in our restricted cash balances during the year ended December 31, 2018, were primarily reflected as increases in cash provided by operating activities as a result of our adoption of this guidance.

The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the balance sheets as of December 31, 2018 and 2017:



	December 31, 2018									December 31, 2017
Ameren			Ameren Missouri			Ameren Illinois			Ameren		Ameren Missouri		Ameren Illinois
Cash and cash equivalents	$	16		$	—		$	—		$	10	$	—	$	—
Restricted cash included in “Other current assets”	13			4			6			21		5		6
Restricted cash included in “Other assets”	74			—			74			35		—		35
Restricted cash included in “Nuclear decommissioning trust fund”	4			4			—			2		2		—
Total cash, cash equivalents, and restricted cash	$	107		$	8		$	80		$	68	$	7	$	41

Restricted cash included in Ameren’s other current assets primarily represents participant funds from Ameren (parent)’s DRPlus and funds held by an irrevocable Voluntary Employee Beneficiary Association (VEBA) trust, which provides health care benefits for active employees. Restricted cash included in Ameren Missouri’s and Ameren Illinois’ other current assets primarily represents funds held by the VEBA trust.

Restricted cash included in Ameren’s and Ameren Illinois’ other assets primarily represents amounts in a trust fund restricted for the use of funding certain asbestos-related claims and amounts collected under a cost recovery rider that are restricted for use in the procurement of renewable energy credits.

Accounts Receivable

“Accounts receivable – trade” on Ameren’s and Ameren Illinois’ balance sheets include certain receivables purchased at a discount from alternative retail electric suppliers that elect to participate in the utility consolidated billing program. At December 31, 2018 and 2017, “Other current liabilities” on Ameren’s and Ameren Illinois’ balance sheets included payables for purchased receivables of $33 million and $31 million, respectively.

For the years ended December 31, 2018, 2017, and 2016 the Ameren Companies recorded immaterial bad debt expense.

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.

Inventories

Inventories are recorded at the lower of weighted-average cost or net realizable value. Inventories are capitalized when purchased and then expensed as consumed or capitalized as property, plant, and equipment when installed, as appropriate. The following table presents a breakdown of inventories for each of the Ameren Companies at December 31, 2018 and 2017:



	Ameren Missouri		Ameren Illinois		Ameren
2018
Fuel(a)	$	123	$	—	$	123
Natural gas stored underground	7		64		71
Materials, supplies, and other	228		61		289
Total inventories	$	358	$	125	$	483
2017
Fuel(a)	$	154	$	—	$	154
Natural gas stored underground	8		74		82
Materials, supplies, and other	226		60		286
Total inventories	$	388	$	134	$	522


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

Property, Plant, and Equipment, Net

We capitalize the cost of additions to, and betterments of, units of property, plant, and equipment. 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 section below and Note 3 – Property, Plant, and Equipment, Net for additional information.

Ameren Missouri’s cost of nuclear fuel is capitalized as a part of “Property, Plant, and Equipment, Net” on the balance sheet 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.

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 2018, 2017, and 2016 ranged from 3% to 4% of the average depreciable cost. See Note 3 – Property, Plant, and Equipment, Net for additional information on estimated depreciable lives.

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 and GAAP. 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 average allowance for funds used during construction debt and equity blended rates that were applied to construction projects in 2018, 2017, and 2016:



	2018		2017		2016
Ameren Missouri	7	%	7	%	7	%
Ameren Illinois	5	%	4	%	5	%

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 had goodwill of $411 million at December 31, 2018 and 2017. Ameren has four reporting units: Ameren Missouri, Ameren Illinois Electric Distribution, Ameren Illinois Natural Gas, and Ameren Transmission. Ameren Illinois has three reporting units: Ameren Illinois Electric Distribution, Ameren Illinois Natural Gas, and Ameren Illinois Transmission. Ameren Illinois Electric Distribution, Ameren Illinois Natural Gas, and Ameren Illinois Transmission had goodwill of $238 million, $80 million, and $93 million, respectively, at December 31, 2018 and 2017. The Ameren Transmission reporting unit had the same $93 million of goodwill as the Ameren Illinois Transmission reporting unit at December 31, 2018 and 2017.

Ameren and Ameren Illinois evaluate goodwill for impairment in each of their reporting units 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 their reporting units below their carrying amounts. To determine whether the fair value of a reporting unit is more likely than not greater than its carrying amount, Ameren and Ameren Illinois elect to perform either a qualitative assessment or to bypass the qualitative assessment and perform a quantitative test, on an annual basis.

Ameren and Ameren Illinois elected to perform a qualitative assessment for their annual goodwill impairment test conducted as of October 31, 2018. The results of Ameren’s and Ameren Illinois’ qualitative assessment indicated that it was more likely than not that the fair value of each reporting unit significantly exceeded its carrying value as of October 31, 2018, resulting in no impairment of Ameren’s or Ameren Illinois’ goodwill. The following factors, among others, were considered by Ameren and Ameren Illinois when they assessed whether it was more likely than not that the fair value of each of their reporting units exceeded its carrying value as of October 31, 2018:


•	macroeconomic conditions, including those conditions within Ameren Illinois’ service territory;


•	pending regulatory rate review outcomes and projections of future regulatory rate review outcomes;


•	changes in laws and potential law changes;


•	observable industry market multiples;


•	achievement of IEIMA and FEJA performance metrics and the yield of the 30-year United States Treasury bonds;


•	changes in the FERC-allowed return on equity with respect to transmission services; and


•	projected operating results and cash flows.

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 that 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 2018 and 2017.

Variable Interest Entities

As of December 31, 2018, Ameren and Ameren Missouri had interests in unconsolidated variable interest entities that were established to construct wind generation facilities and, ultimately, sell those constructed facilities to Ameren Missouri. Neither Ameren nor Ameren Missouri are the primary beneficiary of these variable interest entities because neither has the power to direct matters that most significantly affect the entities' activities, which include designing, financing, and constructing the wind generation facilities. As a result, these variable interest entities are not required to be consolidated. As of December 31, 2018, the maximum exposure to loss related to these variable interest entities was approximately $16 million, which represents the portion of interconnection study costs that may be incurred by Ameren and Ameren Missouri. The risk of a loss was assessed to be remote and, accordingly, Ameren and Ameren Missouri have not recognized a liability associated with any portion of the maximum exposure to loss. See Note 2 – Rate and Regulatory Matters for additional information on the agreements to acquire these wind generation facilities.

As of December 31, 2018 and 2017, Ameren also had investments in unconsolidated variable interest entities totaling $22 million and $17 million, respectively, included in “Other assets” on Ameren’s consolidated balance sheet. These investments are accounted for as equity method investments. Ameren is not the primary beneficiary of these variable interest entities because it does not have the power to direct matters that most significantly affect the entities' activities. As a result, these variable interest entities are not required to be consolidated. As of December 31, 2018, the maximum exposure to loss related to these variable interest entities is limited to the investment in these partnerships of $22 million plus associated outstanding funding commitments of $16 million.

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 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 capitalize a corresponding amount as part of the book value of the related long-lived asset. In subsequent periods, we adjust AROs based on changes in the estimated fair values of the obligations with a corresponding increase or decrease in the asset book value. Asset book values, reflected within “Property, Plant, and Equipment, Net” on the balance sheet, are depreciated over the remaining useful life of the related asset. Due to regulatory recovery, that depreciation is deferred as a regulatory balance. The depreciation of the asset book values at Ameren Missouri was $14 million, $26 million, and $31 million for the years ended December 31, 2018, 2017, and 2016, respectively, which was deferred as a reduction to the net regulatory liability. The net regulatory liability also reflects deferrals of net realized and unrealized gains and losses within the nuclear decommissioning trust fund for the Callaway energy center. The depreciation deferred to the regulatory asset at Ameren Illinois was immaterial in each respective period. 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, 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. Asset removal costs 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, 2018 and 2017:



	Ameren Missouri				Ameren Illinois				Ameren
Balance at December 31, 2016	$	644			$	6			$	650
Liabilities settled	(12		)		(1		)		(13		)
Accretion(a)	26				—				26
Change in estimates(b)	(18		)		(1		)		(19		)
Balance at December 31, 2017	$	640		(c)	$	4		(d)	$	644		(c)
Liabilities settled	(7		)		—				(7		)
Accretion(a)	27				—				27
Change in estimates(e)	(14		)		—				(14		)
Balance at December 31, 2018	$	646		(c)	$	4		(d)	$	650		(c)


(a)	Ameren Missouri’s accretion expense was deferred as a decrease to regulatory liabilities.


(b)	Ameren Missouri changed its fair value estimate primarily because of an extension of the remediation period of certain CCR storage facilities, an update to the decommissioning of the Callaway energy center to reflect the cost study and funding analysis filed with the MoPSC in 2017, and an increase in the assumed discount rate.


(c)	Balance included $23 million and $6 million in “Other current liabilities” on the balance sheet as of December 31, 2018 and 2017, respectively.


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


(e)	Ameren Missouri changed its fair value estimate primarily due to a reduction in the cost estimate for closure of certain CCR storage facilities.

Company-owned Life Insurance

Ameren and Ameren Illinois have company-owned life insurance, which is recorded at the net cash surrender value. The net cash surrender value is the amount that can be realized under the insurance policies at the balance sheet date. As of December 31, 2018, the cash surrender value of company-owned life insurance at Ameren and Ameren Illinois was $244 million (December 31, 2017 – $265 million) and $122 million (December 31, 2017 – $129 million), respectively, while total borrowings against the policies were $113 million (December 31, 2017 – $120 million) at both Ameren and Ameren Illinois. Ameren and Ameren Illinois have the right to offset the borrowings against the cash surrender value of the policies and, consequently, present the net asset in “Other assets” on their respective balance sheets.

Noncontrolling Interests

As of December 31, 2018 and 2017, Ameren’s noncontrolling interests included the preferred stock of Ameren Missouri and Ameren Illinois.

Operating Revenues

In the first quarter of 2018, we adopted authoritative accounting guidance related to revenue from contracts with customers using the full retrospective method, with no material changes to the amount or timing of revenue recognition. We record revenues from contracts with customers for various electric and natural gas services, which primarily consist of retail distribution, electric transmission, and off-system arrangements. When more than one performance obligation exists in a contract, the consideration under the contract is allocated to the performance obligations based on the relative standalone selling price.

Electric and natural gas retail distribution revenues are earned when the commodity is delivered to our customers. We accrue an estimate of electric and natural gas retail distribution revenues for service provided but unbilled at the end of each accounting period.

Electric transmission revenues are earned as electric transmission services are provided.

Off-system revenues are primarily comprised of MISO revenues and wholesale bilateral revenues. MISO revenues include the sale of electricity, capacity, and ancillary services. Wholesale bilateral revenues include the sale of electricity and capacity. MISO-related electricity and wholesale bilateral electricity revenues are earned as electricity is delivered. MISO-related capacity and ancillary service revenues and wholesale bilateral capacity revenues are earned as services are provided.

Retail distribution, electric transmission, and off-system revenues, including the underlying components described above, represent a series of goods or services that are substantially the same and have the same pattern of transfer over time to our customers. Revenues from contracts with customers are equal to the amounts billed and our estimate of electric and natural gas retail distribution services provided but unbilled at the end of each accounting period. Revenues are billed at least monthly, and payments are due less than one month after goods and/or services are provided. See Note 15 – Segment Information for disaggregated revenue information.

For certain regulatory recovery mechanisms that are alternative revenue programs rather than revenues from contracts with customers, we recognize revenues that have been authorized for rate recovery, are objectively determinable and probable of recovery, and are expected to be collected from customers within two years from the end of the year. Our alternative revenue programs include revenue requirement reconciliations, MEEIA, and VBA. These revenues are subsequently recognized as revenues from contracts with customers when billed, with an offset to alternative revenue program revenues.

The Ameren Companies elected not to disclose the aggregate amount of the transaction price allocated to the performance obligations that are unsatisfied as of the end of the reporting period for contracts with an initial expected term of one year or less. As of December 31, 2018 and 2017, our remaining performance obligations were immaterial.

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. Revenues are recognized once the resettlement amount is received. There were no material MISO resettlements in 2018, 2017, or 2016.

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 vesting period. See Note 11 – Stock-based Compensation for additional information.

Deferred Compensation

As of December 31, 2018, and 2017, “Other deferred credits and liabilities” on Ameren’s balance sheet included deferred compensation obligations of $80 million and $86 million, respectively, recorded at the present value of future benefits to be paid.

Excise Taxes

Ameren Missouri and Ameren Illinois collect from their customers excise taxes, including municipal and state excise taxes and gross receipts taxes, that are levied on the sale or distribution of natural gas and electricity. The following table presents the excise taxes recorded on a gross basis in “Operating Revenues – Electric,” “Operating Revenues – Natural gas” and “Operating Expenses – Taxes other than income taxes” on the statements of income for the years ended December 31, 2018, 2017, and 2016:



	2018		2017			2016
Ameren Missouri	$	164	$	153		$	151
Ameren Illinois	118		112		(a)	108		(a)
Ameren	$	282	$	265		$	259


(a)	Amounts have been adjusted from those previously reported to reflect additional excise taxes for the years ended December 31, 2017 and 2016.

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 agreement fees are amortized over the term of the agreement.

Income Taxes

Ameren uses an asset and liability approach for its financial accounting and reporting of income taxes. 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 expect that regulators will reduce future revenues for deferred tax liabilities that were initially recorded at rates in excess of the current statutory rate. Therefore, reductions in certain 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 increases. To the extent deferred tax balances are included in rate base, the revaluation of deferred taxes is recorded as a regulatory asset or liability on the balance sheet and will be collected from, or refunded to, customers. For deferred tax balances not included in rate base, the revaluation of deferred taxes is recorded as an adjustment to income tax expense on the income statement. See Note 12 – Income Taxes for further information regarding the revaluation of deferred taxes related to the TCJA and Missouri and Illinois state corporate income tax rate changes.

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 using a stand-alone calculation, which is similar to that which would be owed or refunded had the party been separately subject to tax considering the impact of consolidation. Any net benefit attributable to Ameren (parent) is reallocated to the other parties. This reallocation is treated as a capital contribution to the party receiving the benefit. See Note 13 – Related-party Transactions for information regarding capital contributions under the tax allocation agreement.

Earnings per Share

Earnings per basic and diluted share are computed by dividing “Net Income Attributable to Ameren Common Shareholders” by the weighted-average number of basic and diluted common shares outstanding, respectively, during the period. Earnings per diluted share reflects the potential dilution that would occur if certain stock-based performance share units and restricted stock units were settled. The number of shares from performance share units assumed to be settled was 2.0 million, 1.6 million, and 0.8 million for the years ended December 31, 2018, 2017, and 2016, respectively. The number of shares from restricted stock units assumed to be settled was immaterial for the year ended December 31, 2018, and not applicable for the years ended December 31, 2017 and 2016. There were no potentially dilutive securities excluded from the diluted earnings per share calculations for the years ended December 31, 2018, 2017, and 2016.

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.

In the first quarter of 2018, the Ameren Companies adopted authoritative accounting guidance on various topics. See the Operating Revenues section above for more information on our adoption of the guidance on revenue from contracts with customers. See Note 10 – Retirement Benefits for more information on our adoption of the guidance on the presentation of net periodic pension and postretirement benefit cost. See the Cash, Cash Equivalents, and Restricted Cash section above for more information on our adoption of the guidance on

restricted cash. Our adoption of the guidance on the recognition and measurement of financial assets and financial liabilities did not have a material impact on our results of operations or financial position.

Leases

In February 2016, the FASB issued authoritative guidance that requires an entity to recognize assets and liabilities arising from all leases with a term greater than one year. This guidance will affect the Ameren Companies’ financial position by increasing the assets and liabilities recorded relating to operating leases. Ameren expects both its assets and liabilities to increase by approximately $40 million, largely due to an increase at Ameren Missouri. We do not expect the impacts of this guidance to be material to our results of operations or cash flows. Consistent with current GAAP, the recognition, measurement, and presentation of expenses and cash flows arising from a lease will depend on its classification as a finance lease 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. We will adopt this guidance using the January 1, 2019 effective date as the date of our application of the standard. No adjustment to comparative periods will be made. This guidance will be effective for the Ameren Companies in the first quarter of 2019. See Note 14 – Commitments and Contingencies for additional information on our leases.

Measurement of Credit Losses on Financial Instruments

In June 2016, the FASB issued authoritative guidance that requires an entity to recognize an allowance for financial instruments that reflects its current estimate of credit losses expected to be incurred over the life of the financial instruments. The guidance requires an entity to measure expected credit losses using relevant information about past events, current conditions, and reasonable and supportable forecasts that affect the collectibility of the reported amount. We are currently assessing the impacts of this guidance on our results of operations, financial position, and disclosures. This guidance will be effective for the Ameren Companies in the first quarter of 2020, and will require changes to be applied retrospectively with a cumulative effect adjustment to retained earnings as of the adoption date.

Fair Value Measurement Disclosures

In August 2018, the FASB issued authoritative guidance that affects disclosure requirements for fair value measurements. This guidance will be effective for the Ameren Companies in the first quarter of 2020, with early adoption permitted. We are currently assessing the impacts of this guidance on our disclosures.

Defined Benefit Plan Disclosures

In August 2018, the FASB issued authoritative guidance that affects disclosure requirements for defined benefit plans. This guidance will be effective for the Ameren Companies in the fourth quarter of 2020, and will require changes to be applied retrospectively to each period presented. Early adoption is permitted. We are currently assessing the impacts of this guidance on our disclosures.

Implementation Costs Incurred in Certain Cloud Computing Arrangements

In August 2018, the FASB issued authoritative guidance that aligns the requirements for capitalizing implementation costs incurred in certain hosting arrangements with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. This guidance requires capitalized implementation costs to be expensed over the term of the hosting arrangement and presented in the same line item in the statement of income as the fees of the associated hosting arrangement. Capitalized implementation costs must be presented in the balance sheet in the same line item that a prepayment for the fees of the associated hosting arrangement would be presented, and payments for capitalized implementation costs must be classified in the statement of cash flows in the same manner as payments for hosting arrangement fees. The Ameren Companies early adopted this guidance in the third quarter of 2018 and applied the guidance prospectively to all implementation costs incurred after the date of adoption. Implementation costs capitalized in 2018 were immaterial.

Classification of Certain Cash Receipts and Cash Payments

In August 2016, the FASB issued authoritative guidance that specifies the classification and presentation of certain cash flow items to reduce diversity in practice. This guidance was effective for the Ameren Companies in the first quarter of 2018 and was applied retrospectively. Our adoption of this guidance did not result in material changes to previously reported cash flows from operating, investing, or financing activities.

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 final decisions of the various agencies and courts, or the effect on our results of operations, financial position, or liquidity.

Missouri

Missouri Senate Bill 564

On June 1, 2018, Missouri Senate Bill 564 was enacted. The provision of the law applicable to the TCJA was effective immediately; the remaining provisions, including the ability to elect PISA, became effective August 28, 2018. The law required the MoPSC to authorize a reduction in Ameren Missouri’s rates to pass through the effect of the TCJA within 90 days of the law’s effective date. In July 2018, the MoPSC authorized Ameren Missouri to reduce its annual revenue requirement by $167 million and reflect that reduction in rates beginning August 1, 2018. The reduction included $74 million for the amortization of excess accumulated deferred income taxes. In addition, Ameren Missouri recorded a reduction to revenue and a corresponding regulatory liability of $60 million for the excess amounts collected in rates related to the TCJA from January 1, 2018, through July 31, 2018. The regulatory liability will be reflected in customer rates over a period of time to be determined by the MoPSC in the next regulatory rate review.

Pursuant to its PISA election, Ameren Missouri is permitted to defer and recover 85% of the depreciation expense and a weighted-average cost of capital return on rate base on certain property, plant, and equipment placed in service after September 1, 2018, and not included in base rates. The rate base on which the return is calculated incorporates qualifying capital expenditures since the PISA election date, and changes in total accumulated depreciation excluding retirements and plant-related deferred income taxes. The debt return on rate base is recognized in earnings as a reduction of “Interest Charges” until PISA deferrals are reflected in customer rates, while the equity return is recognized in earnings as “Operating Revenues – Electric” when billed to customers. Accumulated PISA deferrals earn carrying costs at the weighted-average cost of capital, and all approved PISA deferrals will be added to rate base prospectively and recovered over a period of 20 years following a regulatory rate review. PISA mitigates the impacts of regulatory lag between regulatory rate reviews. The remaining 15% of certain property, plant, and equipment placed in service and not eligible for recovery under PISA, unless eligible for recovery under the RESRAM, remain subject to regulatory lag. See below for discussion of the RESRAM. Amounts deferred under PISA were immaterial as of December 31, 2018.

As a result of Ameren Missouri’s PISA election, additional provisions of Missouri law apply, including provisions limiting customer rate increases to a 2.85% compound annual growth rate in the average overall customer rate per kilowatthour, based on the electric rates that became effective in April 2017, less half of the annual savings from the TCJA that was passed on to customers as approved in the July 2018 MoPSC order. Additionally, Ameren Missouri’s electric base rates, as determined in the July 2018 MoPSC order, are frozen until April 1, 2020. Customer rates under the MEEIA, the FAC, and the RESRAM riders have not been frozen. If rate changes from the FAC or the RESRAM riders would cause rates to temporarily exceed the 2.85% rate cap, the overage would be deferred for future recovery in the next regulatory rate review; however, rates established in such regulatory rate review will be subject to the rate cap. Any deferred overages approved for recovery will be recovered in a manner consistent with costs recovered under PISA. Excluding customer rates under the MEEIA rider, which are not subject to the rate cap, Ameren Missouri would incur a penalty equal to the amount of deferred overage that would cause customer rates to exceed the 2.85% rate cap. Both the rate cap and PISA election are effective through December 2023, unless Ameren Missouri requests and receives MoPSC approval of an extension through December 2028.

Wind Generation Facilities and RESRAM

In the second quarter of 2018, Ameren Missouri entered into a build-transfer agreement with a subsidiary of Terra-Gen, LLC to acquire, after construction, a 400-megawatt wind generation facility, which is expected to be located in northeastern Missouri. In October 2018, the MoPSC issued an order approving a unanimous stipulation and agreement regarding a requested certificate of convenience and necessity for the facility. In December 2018, Ameren Missouri received FERC approval to acquire the facility after construction. A transmission interconnection agreement with the MISO for this facility is expected in the fall of 2019. Also, in October 2018, Ameren Missouri entered into a build-transfer agreement with a subsidiary of EDF Renewables, Inc. to acquire, after construction, a wind generation facility of up to 157 megawatts. In February 2019, Ameren Missouri filed with the MoPSC a nonunanimous stipulation and agreement regarding a requested certificate of convenience and necessity for the facility. The up to 157-megawatt facility is expected to be located in northwestern Missouri. A transmission interconnection agreement with the MISO for this facility is expected in early 2020. Both facilities are expected to be completed by the end of 2020 and would help Ameren Missouri comply with the Missouri renewable energy standard. Each acquisition is subject to certain conditions, including entering into a MISO transmission interconnection agreement at an acceptable cost for each facility and obtaining FERC approval and the issuance of a certificate of convenience and necessity by the MoPSC for the up to 157-megawatt facility, as well as other customary contract terms and conditions. These agreements collectively represent approximately $1 billion in capital expenditures expected in 2020, which is included in Ameren Missouri’s Smart Energy Plan.

As a part of its May 2018 filing, Ameren Missouri requested the MoPSC to authorize a proposed RESRAM that would allow Ameren Missouri to adjust customer rates on an annual basis without a traditional regulatory rate review. In October and December 2018, the MoPSC issued orders approving the RESRAM. In January 2019, the MoOPC filed an appeal with the Missouri Court of Appeals, Western District, challenging the MoPSC’s December 2018 order allowing Ameren Missouri to recover, through the RESRAM, the 15% of capital investment not recovered under PISA. Ameren Missouri expects a decision by the end of 2019. The RESRAM is designed to mitigate the impacts of

regulatory lag for the cost of compliance with renewable energy standards, including recovery of investments in wind and other renewable generation, by providing more timely recovery of costs and a return on investments not already provided for in customer rates or recovered under PISA. RESRAM regulatory assets earn carrying costs at short-term interest rates.

Renewable Choice Program

In June 2018, the MoPSC approved Ameren Missouri’s Renewable Choice Program, which allows large commercial and industrial customers and municipalities to elect to receive up to 100% of their energy from renewable resources. The tariff-based program is designed to recover the costs of the election, net of changes in the market price of such energy. Based on customer contracts, the program enables Ameren Missouri to supply up to 400 megawatts of renewable wind energy generation, up to 200 megawatts of which it could own. As applicable, the addition of generation by Ameren Missouri would be subject to the issuance of a certificate of convenience and necessity by the MoPSC, obtaining transmission interconnection agreements with MISO or other RTOs, and FERC approval. Ameren Missouri anticipates finalizing customer interest and pursuing renewable energy projects to fulfill requirements in 2019. Without extension, the option to elect into the program will terminate in the third quarter of 2023.

MEEIA

In July 2018, the Missouri Supreme Court overturned a 2016 decision by the Missouri Court of Appeals, Western District, which had upheld a 2015 MoPSC order regarding the determination of a certain input used to calculate the MEEIA 2013 performance incentive, and remanded the matter to the MoPSC. In January 2019, the MoPSC issued an order approving an additional $9 million MEEIA 2013 performance incentive. Accordingly, Ameren Missouri recognized the additional performance incentive in the first quarter of 2019. In November 2016, the MoPSC approved a $28 million MEEIA 2013 performance incentive based on a stipulation and agreement among Ameren Missouri, the MoPSC staff, and the MoOPC. Ameren Missouri collected $28 million of the performance incentive over a two-year period that began in February 2017.

The MEEIA 2016 plan provides Ameren Missouri with a performance incentive 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 beginning March 2016, with the potential to earn more if Ameren Missouri’s energy savings exceed those goals. In September 2017, Ameren Missouri received an order from the MoPSC approving Ameren Missouri’s energy savings results for the first year of the MEEIA 2016 plan. In October 2018, Ameren Missouri received an order from the MoPSC approving Ameren Missouri’s energy savings results for the second year of the MEEIA 2016 plan. As a result of these orders and in accordance with revenue recognition guidance, Ameren Missouri recognized $5 million of revenues in the first quarter of 2018, $6 million of additional revenues in the fourth quarter of 2018, and $11 million of additional revenues in the first quarter of 2019 relating to the MEEIA 2016 performance incentive.

In December 2018, the MoPSC issued an order approving Ameren Missouri’s MEEIA 2019 plan. The plan includes a portfolio of customer energy-efficiency programs through December 2021 and low-income customer energy-efficiency programs through December 2024, along with a regulatory recovery mechanism. Ameren Missouri intends to invest $226 million over the life of the plan, including $65 million per year through 2021. The plan includes the continued use of the MEEIA rider, which allows Ameren Missouri to collect from, or refund to, customers any difference in actual MEEIA program costs and related lost electric margins and the amounts collected from customers. In addition, the plan includes a performance incentive that provides Ameren Missouri an opportunity to earn additional revenues by achieving certain customer energy-efficiency goals, including $30 million if 100% of the goals are achieved during the period ended December 2021. Additional revenues may be earned if Ameren Missouri exceeds 100% of its energy savings goals.

2018 Natural Gas Delivery Service Regulatory Rate Review

In December 2018, Ameren Missouri filed a request with the MoPSC to increase its annual revenues for natural gas delivery service by approximately $4 million. The natural gas delivery service rate increase request was based on a 10.30% return on equity, a capital structure composed of 51.84% common equity, a rate base of $259 million, and a test year ended June 30, 2018, with certain pro-forma adjustments through the anticipated true-up date of May 31, 2019. In December 2018, the MoPSC issued an order approving a stipulation and agreement for an interim rate reduction of $2 million to reflect cost of service updates including the reduction in the federal corporate income tax rate and the amortization of excess deferred taxes as a result of the TCJA. The interim rate reduction became effective January 2, 2019, and will continue until new rates are approved by the MoPSC in this regulatory rate review.

Mark Twain Project Return on Equity Incentive Adder

In November 2018, the FERC issued an order approving a 50 basis point return on equity incentive adder for the Mark Twain project, effective as of February 14, 2018, based on the unique nature of risks involved in the project. This incentive adder is in addition to the current 50 basis point incentive adder for participation in an RTO and the total return on equity, inclusive of all incentive adders, is subject to the top of the zone of reasonableness. The impact to Ameren’s 2018 earnings was immaterial.

Illinois

IEIMA & FEJA

Under a formula ratemaking framework effective through 2022, Ameren Illinois’ electric distribution service rates are subject to an annual revenue requirement reconciliation to its actual recoverable costs and allowed return on equity. The formula ratemaking framework qualifies as an alternative revenue program under GAAP. 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. As of December 31, 2018, Ameren Illinois had recorded regulatory assets of $16 million and $54 million, including interest, to reflect its expected 2018 and its approved 2017 revenue requirement reconciliation adjustments, respectively. As of December 31, 2017, Ameren Illinois had recorded a $24 million regulatory asset to reflect its approved 2016 revenue requirement reconciliation adjustment, which was collected, with interest, from customers during 2018.

In November 2018, the ICC issued an order in Ameren Illinois’ annual update filing that approved a $72 million increase in Ameren Illinois’ electric distribution service rates beginning in January 2019. This order reflected an increase to the annual formula rate based on 2017 actual costs and expected net plant additions for 2018, and an increase to include the 2017 revenue requirement reconciliation adjustment. It also included a decrease for the conclusion of the 2016 revenue requirement reconciliation adjustment, which was fully collected from customers in 2018, consistent with the ICC’s December 2017 annual update filing order.

The FEJA revised certain portions of the IEIMA, including extending the IEIMA formula ratemaking framework through 2022, and clarifying that a common equity ratio up to and including 50% is prudent. Beginning in 2017, the FEJA permitted Ameren Illinois to recover, within the following two years, its electric distribution revenue requirement for a given year, independent of actual sales volumes.

The FEJA allows Ameren Illinois to earn a return on its electric energy-efficiency program investments. Ameren Illinois’ electric energy-efficiency investments are deferred as a regulatory asset and earn a return at its weighted-average cost of capital, with the equity return based on the annual average of the monthly yields of the 30-year United States Treasury bonds plus 580 basis points. The equity portion of Ameren Illinois’ return on electric energy-efficiency investments can be increased or decreased by up to 200 basis points, depending on the achievement of annual energy savings goals. In 2018, there were no performance-related basis point adjustments. In September 2017, the ICC issued an order approving Ameren Illinois’ implementation of the FEJA electric energy-efficiency savings targets and investments for 2018 through 2021. Ameren Illinois plans to invest approximately $100 million per year in electric energy-efficiency programs through 2023, consistent with targets established by the FEJA. The ICC has the ability to reduce electric energy-efficiency savings goals if there are insufficient cost-effective programs available or if the savings goals would require investment levels that exceed amounts allowed by legislation. The electric energy-efficiency program investments and the return on those investments are collected from customers through a rider and are not included in the electric distribution formula ratemaking framework.

In June 2018, Ameren Illinois filed its annual electric customer energy-efficiency formula rate update to establish the revenue requirement to be used for 2019 rates with the ICC. In November 2018, the ICC issued an order that approved 2019 rates of $35 million for electric customer energy-efficiency investments, which represents an increase of $20 million from 2018 rates.

2018 Natural Gas Delivery Service Regulatory Rate Review

In January 2018, Ameren Illinois filed a request with the ICC seeking approval to increase its annual rates for natural gas delivery service. In November 2018, the ICC issued an order approving a stipulation and agreement that resulted in an annual natural gas rate increase of $32 million, based on a 9.87% return on common equity, a capital structure composed of 50% common equity, and a rate base of $1.6 billion. This increase reflects the reduction in the federal statutory corporate income tax rate enacted under the TCJA, as well as the increase in the Illinois corporate income tax rate that became effective in July 2017, which collectively decreased annual rates by approximately $17 million. The new customer rates were effective in November 2018. As a result of this order, the rate base under the QIP rider was reset to zero. Ameren Illinois used a 2019 future test year in this proceeding.

Income Tax Regulatory Mechanisms

In February 2018, the ICC granted Ameren Illinois’ request, filed in January 2018, to establish a rider to reduce Ameren Illinois’ electric distribution customer rates for the effect of the reduction in the federal statutory corporate income tax rate enacted under the TCJA and the return of excess deferred taxes, net of the increase in state income taxes enacted in July 2017. Ameren Illinois' electric distribution customer rates were reduced as a result of the rider beginning in the first quarter of 2018. The estimated reduction of approximately $50 million per year will continue through 2019, as base rates will be adjusted to reflect the current income tax rates starting in 2020.

In April 2018, the ICC approved a rider for the difference between revenues billed under natural gas rates established pursuant to Ameren Illinois’ most recent natural gas rate order and the revenues that would have been billed had the state and federal tax rate changes

discussed above been in effect. The rider required Ameren Illinois to record this difference as a regulatory liability beginning January 25, 2018. Ameren Illinois’ natural gas customer rates were reduced as a result of the rider beginning in May 2018. As base rates were updated with the November 2018 natural gas rate order discussed above, a reduction of approximately $15 million will be reflected in customer rates substantially over a one-year period.

ATXI’s Illinois Rivers Project

In August 2017, the Illinois Circuit Court for Edgar County dismissed several of ATXI’s condemnation cases related to one line segment in the Illinois Rivers project. These cases had been filed to obtain easements and rights of way necessary to complete the line segment. The court found that required notice was not given to the relevant landowners during the underlying ICC proceeding. Upon appeal, in October 2018, the Illinois Supreme Court reversed the Illinois Circuit Court for Edgar County’s decision and remanded the case for further proceedings. In December 2018, the Illinois Supreme Court issued an order to stay its October 2018 ruling. In February 2019, the landowners filed an appeal with the United States Supreme Court. The October 2018 ruling is further stayed pending resolution of the appeal. Construction of the Illinois Rivers project is substantially complete. Delays associated with the condemnation proceedings or a rehearing arising from the Illinois Supreme Court’s ruling will delay the expected completion date to 2020, which is not expected to materially affect 2019 earnings. The estimated line segment capital expenditure investment is approximately $81 million, of which $38 million was invested as of December 31, 2018. The other eight line segments of the Illinois Rivers project are not affected by these proceedings.

Federal

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 FERC-regulated transmission rate base under the MISO tariff from 12.38% to 9.15%. In September 2016, the FERC issued a final order in the November 2013 complaint case, which lowered the allowed base return on common equity to 10.32%, or a 10.82% total allowed return on common equity with the inclusion of a 50 basis point incentive adder for participation in an RTO, effective since September 2016. In 2017, Ameren and Ameren Illinois refunded $21 million and $17 million, respectively related to the November 2013 complaint case. The 10.82% allowed return on common equity may be replaced prospectively after the FERC issues a final order in the February 2015 complaint case, discussed below.

Since 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. MISO transmission owners subsequently filed a motion to dismiss the February 2015 complaint, as discussed below. The February 2015 complaint case seeks a further reduction in the allowed base return on common equity for FERC-regulated transmission rate base under the MISO tariff. In June 2016, an administrative law judge issued an initial decision in the February 2015 complaint case. If approved by the FERC, it would lower the allowed base return on common equity for the 15-month period of February 2015 to May 2016 to 9.70%, or a 10.20% total allowed return on equity with the inclusion of a 50 basis point incentive adder for participation in an RTO. It would also require customer refunds, with interest, for that 15-month period. A final FERC order would also establish the allowed return on common equity that will apply prospectively from the effective date of such order, replacing the current 10.82% total return on common equity. In the second quarter of 2017, the United States Court of Appeals for the District of Columbia Circuit vacated and remanded to the FERC an order in an unrelated case in which the FERC established the allowed base return on common equity methodology subsequently used in the two MISO complaint cases described above. In October 2018, the FERC issued an order addressing the remanded issues in an unrelated case. That order proposed a new methodology for determining the base return on equity and required further briefs from the participants. In November 2018, the FERC issued an order related to the February 2015 complaint case and the September 2016 final order, which required briefs from the participants to be filed in February 2019 regarding a new methodology for determining the base return on common equity and whether and how to apply the new methodology to the two MISO complaint cases. Ameren is unable to predict the ultimate impact of the proposed methodology on these complaint cases at this time. As the FERC is under no deadline to issue a final order, the timing of the issuance of the final order in the February 2015 complaint case, or any potential impact to the amounts refunded as a result of the September 2016 final order, is uncertain.

In September 2017, MISO transmission owners, including Ameren Missouri, Ameren Illinois, and ATXI, filed a motion to dismiss the February 2015 complaint case with the FERC. The MISO transmission owners maintain that the February 2015 complaint was predicated on the now superseded 12.38% allowed base return on common equity and is therefore inapplicable given the current 10.32% allowed base return on common equity. The MISO transmission owners further maintain that the current 10.32% allowed base return on common equity has not been proven to be unjust and unreasonable based on information provided, including the base return on common equity methodology ranges set forth in the February 2015 complaint case and in the initial decision issued by an administrative law judge in June 2016. Additionally, the MISO transmission owners maintain that the February 2015 complaint should be dismissed because the approach utilized in the case to assert that a return on common equity was unjust and unreasonable was insufficient. That same approach was rejected by the United States Court of Appeals for the District of Columbia Circuit in an unrelated case, as discussed above. The FERC is under no deadline to issue an order on this motion.

As of December 31, 2018, Ameren and Ameren Illinois had recorded current regulatory liabilities of $44 million and $26 million, respectively, to reflect the expected refunds, including interest, associated with the reduced allowed returns on common equity in the initial decision in the February 2015 complaint case. Ameren Missouri does not expect that a reduction in the FERC-allowed base return on common equity would be material to its results of operations, financial position, or liquidity.

FERC Federal Income Tax Proceeding and Formula Rate Change

In March 2018, the FERC granted a request filed in February 2018 by MISO transmission owners with forward-looking rate formulas, including Ameren Illinois and ATXI, to allow revisions to their 2018 electric transmission rates to reflect the effect of the reduction in federal income taxes enacted under the TCJA. Ameren Illinois and ATXI’s 2018 electric transmission rates were reduced by $27 million and $23 million, respectively.

In May 2018, the FERC accepted Ameren Illinois, and ATXI’s tariff filings to change the formula rate calculation. The change allows for the recovery or refund of both excess deferred taxes resulting from tax law or rate changes and the effect of permanent income tax differences and were reflected in Ameren Illinois’ and ATXI’s electric transmission rates starting in January 2019.

Regulatory Assets and Liabilities

The following table presents our regulatory assets and regulatory liabilities at December 31, 2018 and 2017:



	2018									2017
	Ameren Missouri			Ameren Illinois			Ameren				Ameren Missouri			Ameren Illinois			Ameren
Regulatory assets:
Under-recovered FAC(a)	$	3		$	—		$	3			$	47		$	—		$	47
Under-recovered PGA(b)	—			7			7				1			13			14
MTM derivative losses(c)	19			197			216				12			217			229
IEIMA revenue requirement reconciliation adjustment(d)(e)	—			70			70				—			78			78
FERC revenue requirement reconciliation adjustment(f)	—			16			30				—			25			37
Under-recovered VBA rider(g)	—			—			—				—			15			15
Pension and postretirement benefit costs(h)	103			149			252				84			215			299
Income taxes(i)	119			68			185				139			56			197
Callaway costs(e)(j)	22			—			22				25			—			25
Unamortized loss on reacquired debt(k)	58			40			98				61			49			110
Environmental cost riders(l)	—			148			148				—			173			173
Storm costs(e)(m)	—			13			13				—			10			10
Demand-side costs before the MEEIA implementation(e)(n)	5			—			5				11			—			11
Workers’ compensation claims(o)	4			7			11				5			7			12
Construction accounting for pollution control equipment(e)(p)	16			—			16				18			—			18
Solar rebate program(e)(q)	14			—			14				31			—			31
FEJA energy-efficiency riders(e)(r)	—			136			136				—			41			41
Other	17			18			35				17			10			27
Total regulatory assets	$	380		$	869		$	1,261			$	451		$	909		$	1,374
Less: current regulatory assets	(14		)	(110		)	(134		)		(56		)	(87		)	(144		)
Noncurrent regulatory assets	$	366		$	759		$	1,127			$	395		$	822		$	1,230
Regulatory liabilities:
Over-recovered FAC(a)	$	34		$	—		$	34			$	4		$	—		$	4
Over-recovered Illinois electric power costs(b)	—			12			12				—			16			16
Over-recovered PGA(b)	7			3			10				—			1			1
Over-recovered VBA rider(g)	—			8			8				—			—			—
MTM derivative gains(c)	5			3			8				16			—			16
FERC revenue requirement reconciliation adjustment(f)	—			17			19				—			—			—
Energy-efficiency riders(s)	19			3			22				2			40			42
Estimated refund for FERC complaint case(t)	—			26			44				—			25			42
Income taxes(i)	1,484			843			2,413				1,392			842			2,323
Asset removal costs(u)	1,027			774			1,811				995			725			1,725
AROs(v)	175			—			175				223			—			223
Pension and postretirement benefit costs tracker(w)	43			—			43				35			—			35
Renewable energy credits and zero emission credits(x)	—			102			102				—			58			58
Excess income taxes collected in 2018(y)	60			—			60				—			—			—
Other	13			12			25				16			14			30
Total regulatory liabilities	$	2,867		$	1,803		$	4,786			$	2,683		$	1,721		$	4,515
Less: current regulatory liabilities	(68		)	(62		)	(149		)		(19		)	(92		)	$	(128	)
Noncurrent regulatory liabilities	$	2,799		$	1,741		$	4,637			$	2,664		$	1,629		$	4,387


(a)	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.


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


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


(d)	The difference between Ameren Illinois’ electric distribution service annual revenue requirement calculated under the performance-based formula ratemaking framework and the revenue requirement included in customer rates for that year. Any under-recovery or over-recovery will be recovered from, or refunded to, customers with interest within two years.


(e)	These assets earn a return.


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


(g)	Under-recovered or over-recovered natural gas revenue caused by sales volume deviations from weather normalized sales approved by the ICC in rate regulatory reviews. Each year’s amount will be recovered from, or refunded to, customers from April through December of the following year.


(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 10 – Retirement Benefits for additional information.


(i)	The regulatory assets represent deferred income taxes that will be recovered from customers related to the equity component of allowance for funds used during construction and the effects of tax rate changes from the TCJA and the increased income tax rate in Illinois. The regulatory liabilities represent deferred income taxes that will be refunded to customers related to depreciation differences, other tax liabilities, and the unamortized portion of investment tax credits recorded at rates in excess of current statutory rates. Amounts associated with the equity component of allowance for funds used during construction, and the unamortized portion of investment tax credits will be amortized over the expected life of the related assets. The amortization periods for depreciation differences are determined in rate orders by the applicable regulators and range from 7 to 60 years. See Note 12 – Income Taxes for amounts related to the revaluation of deferred income taxes under the TCJA.

(i)

The regulatory assets represent deferred income taxes that will be recovered from customers related to the equity component of allowance for funds used during construction and the effects of tax rate changes from the TCJA and the increased income tax rate in Illinois. The regulatory liabilities represent deferred income taxes that will be refunded to customers related to depreciation differences, other tax liabilities, and the unamortized portion of investment tax credits recorded at rates in excess of current statutory rates. Amounts associated with the equity component of allowance for funds used during construction, and the unamortized portion of investment tax credits will be amortized over the expected life of the related assets. The amortization periods for depreciation differences are determined in rate orders by the applicable regulators and range from 7 to 60 years. See Note 12 – Income Taxes for amounts related to the revaluation of deferred income taxes under the TCJA.


(j)	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 original remaining life of the energy center.


(k)	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.


(l)	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 14 – Commitments and Contingencies for additional information.


(m)	Storm costs from 2015, 2016, and 2018 deferred in accordance with the IEIMA. These costs are being amortized over five-year periods beginning in the year the storm occurred.


(n)	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. The MoPSC’s March 2017 electric rate order modified certain amortization periods for these costs. Costs incurred from May 2008 through September 2008, and from January 2010 through July 2012, are being amortized over a two-year period that began in April 2017. Costs incurred from October 2008 through December 2009 are no longer being amortized as of April 2017, and a new amortization period for these costs will be determined in a future regulatory rate review. Costs incurred from August 2012 through December 2012 are being amortized over a six-year period that began in June 2015.

(n)

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. The MoPSC’s March 2017 electric rate order modified certain amortization periods for these costs. Costs incurred from May 2008 through September 2008, and from January 2010 through July 2012, are being amortized over a two-year period that began in April 2017. Costs incurred from October 2008 through December 2009 are no longer being amortized as of April 2017, and a new amortization period for these costs will be determined in a future regulatory rate review. Costs incurred from August 2012 through December 2012 are being amortized over a six-year period that began in June 2015.


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


(p)	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, currently through 2033.


(q)	Costs associated with Ameren Missouri’s solar rebate program to fulfill its renewable energy requirements. Costs incurred from 2010 to 2014 are being amortized over a two-year period that began in April 2017 as modified per the MoPSC’s March 2017 electric rate order. Costs incurred from 2015 to 2016 are being amortized over a three-year period that began in April 2017.

(r)

Electric energy-efficiency program investment deferrals which earn a return at Ameren Illinois’ weighted-average cost of capital with the equity return based on the annual average of the monthly yields of the 30-year United States Treasury bonds plus 580 basis points. The investments are being amortized over their weighted-average useful lives beginning in the period in which they were made, with current remaining amortization periods ranging from 8 to 12 years.

(s)

The Ameren Missouri balance relates to the MEEIA. The MEEIA rider allows 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, lost electric margins, and the performance incentive. Under the MEEIA rider, collections from or refunds to customers occur one year after the program costs, and lost electric margins are incurred or any performance incentive are earned. The Ameren Illinois balance relates to a regulatory tracking mechanism to recover its electric pre-FEJA costs 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 year following the plan year.


(t)	Estimated refunds to transmission customers related to the February 2015 FERC complaint case discussed above.


(u)	Estimated funds collected for the eventual dismantling and removal of plant retired from service, net of salvage value.


(v)	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.

(w)

A regulatory tracking mechanism for the difference between the level of pension and postretirement benefit costs incurred by Ameren Missouri and the level of such costs included in customer rates. For costs incurred prior to August 2012, the amounts are being amortized over a two-year period that began in April 2017 as modified per the MoPSC’s March 2017 electric rate order. For costs incurred between August 2012 and December 2014, the MoPSC’s May 2015 electric rate order directed the amortization period to occur over a five-year period that began in June 2015. For costs incurred between January 2015 and December 2016, the MoPSC’s March 2017 electric rate order directed the amortization period to occur over a five-year period that began in April 2017. For costs incurred after December 2016, the amortization period will be determined in a future electric regulatory rate review.


(x)	Funds collected for the purchase of renewable energy credits and zero emission credits through IPA procurements. The balance will be amortized as the credits are purchased.


(y)	The excess amount collected in rates related to the TCJA from January 1, 2018, through July 31, 2018. The regulatory liability will be reflected in customer rates over a period of time to be determined by the MoPSC in the next regulatory rate review.

NOTE 3 – PROPERTY, PLANT, AND EQUIPMENT, NET

The following table presents property, plant, and equipment, net, for each of the Ameren Companies at December 31, 2018 and 2017:



	Ameren Missouri(a)		Ameren Illinois		Other		Ameren(a)
2018
Property, plant, and equipment at original cost:(b)
Electric generation	$	11,432	$	—	$	—	$	11,432
Electric distribution	5,989		5,970		—		11,959
Electric transmission	1,277		2,647		1,385		5,309
Natural gas	500		2,701		—		3,201
Other(c)	1,008		863		230		2,101
	20,206		12,181		1,615		34,002
Less: Accumulated depreciation and amortization	8,726		3,294		253		12,273
	11,480		8,887		1,362		21,729
Construction work in progress:
Nuclear fuel in process	217		—		—		217
Other	406		311		147		864
Property, plant, and equipment, net	$	12,103	$	9,198	$	1,509	$	22,810
2017
Property, plant, and equipment at original cost:(b)
Electric generation	$	11,132	$	—	$	—	$	11,132
Electric distribution	5,766		5,649		—		11,415
Electric transmission	1,201		2,298		1,167		4,666
Natural gas	474		2,419		—		2,893
Other(c)	922		757		242		1,921
	19,495		11,123		1,409		32,027
Less: Accumulated depreciation and amortization	8,305		3,082		246		11,633
	11,190		8,041		1,163		20,394
Construction work in progress:
Nuclear fuel in process	148		—		—		148
Other	413		252		259		924
Property, plant, and equipment, net	$	11,751	$	8,293	$	1,422	$	21,466

(a)

Amounts in Ameren and Ameren Missouri include two CTs under separate agreements. The gross cumulative asset value of those agreements was $235 million and $233 million at December 31, 2018 and 2017, respectively. The total accumulated depreciation associated with the two CTs was $89 million and $83 million at December 31, 2018 and 2017, respectively. See Note 5 – Long-term Debt and Equity Financings for additional information on these agreements.


(b)	The estimated lives for each asset group are as follows: 5 to 72 years for electric generation, excluding Ameren Missouri’s hydro generating assets which have useful lives of up to 150 years, 20 to 80 years for electric distribution, 50 to 75 years for electric transmission, 20 to 80 years for natural gas, and 5 to 55 years for other.


(c)	Other property, plant, and equipment includes assets used to support electric and natural gas services.

Capitalized software costs are classified within “Property, Plant, and Equipment, Net” on the balance sheet and are amortized on a straight-line basis over the expected period of benefit, ranging from 5 to 10 years. The following table presents the amortization expense of capitalized software, the gross carrying value of capitalized software, and the related accumulated amortization by year:



	Amortization Expense(a)						Gross Carrying Value				Accumulated Amortization
	2018		2017		2016		2018		2017		2018			2017
Ameren	$	71	$	58	$	52	$	734	$	655	$	(514	)	$	(466	)
Ameren Missouri	24		20		17		223		191		(125		)	(107		)
Ameren Illinois	44		36		33		297		241		(183		)	(146		)


(a)	As of December 31, 2018, the estimated amortization expense of capitalized software for each of the five succeeding years is not expected to differ materially from the current year expense.

The following table provides accrued capital and nuclear fuel expenditures at December 31, 2018, 2017, and 2016, which represent noncash investing activity excluded from the accompanying statements of cash flows:



	Ameren		Ameren Missouri		Ameren Illinois
Accrued capital expenditures:
2018	$	272	$	121	$	138
2017	361		159		175
2016	251		116		87
Accrued nuclear fuel expenditures:
2018	$	20	$	20	$	—
2017	10		10		—
2016	20		20		—

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 affiliate borrowings.

Credit Agreements

In December 2018, the Credit Agreements, which were scheduled to mature in December 2021, were extended and now mature in December 2022. The Credit Agreements provide $2.1 billion of credit cumulatively through maturity. The maturity date may be extended for an additional one-year period upon mutual consent of the borrowers and lenders. Credit available under the agreements is provided by a group of 22 international, national, and regional lenders, with no single lender providing more than $118 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 (parent) or any other subsidiary of Ameren. The following table presents the maximum aggregate amount available to each borrower under each facility:



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


(a)	Not applicable.

The borrowers have 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. Ameren (parent) borrowings are due and payable no later than the maturity date of the Credit Agreements. Ameren Missouri and Ameren Illinois borrowings under the applicable Credit Agreement are due and payable no later than the earlier of the maturity date or 364 days after the originating date of the borrowing.

The obligations of the 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 affiliate loan arrangements. 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, subject to borrowing sublimits. As of December 31, 2018, based on commercial paper outstanding and letters of credit issued under the Credit Agreements, along with cash and cash equivalents, the net liquidity available to Ameren (parent), Ameren Missouri, and Ameren Illinois, collectively, was $1.5 billion.

Ameren, Ameren Missouri, and Ameren Illinois did not borrow under the Credit Agreements for the years ended December 31, 2018 and 2017.

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, 2018 and 2017:



	Ameren (parent)			Ameren Missouri			Ameren Illinois			Ameren Consolidated
2018
Average daily commercial paper outstanding	$	410		$	61		$	108		$	579
Outstanding borrowings at period-end	470			55			72			597
Weighted-average interest rate	2.31		%	1.94		%	2.26		%	2.26		%
Peak outstanding commercial paper during period(a)	$	543		$	481		$	442		$	1,295
Peak interest rate	3.10		%	2.80		%	2.85		%	3.10		%
2017
Average daily commercial paper outstanding	$	573		$	5		$	90		$	668
Outstanding borrowings at period-end	383			39			62			484
Weighted-average interest rate	1.30		%	1.24		%	1.35		%	1.31		%
Peak outstanding commercial paper during period(a)	$	841		$	64		$	469		$	948
Peak interest rate	1.90		%	1.78		%	2.00		%	2.00		%


(a)	The timing of peak outstanding commercial paper issuances varies by company. Therefore, the sum of the peak amounts presented by the companies may not equal the Ameren consolidated peak amount 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 conditions 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 obtaining 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 certain 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, 2018, the ratios of consolidated indebtedness to total consolidated capitalization, calculated in accordance with the provisions of the Credit Agreements, were 53%, 47%, and 48%, for Ameren, Ameren Missouri, and Ameren Illinois, respectively.

The Credit Agreements contain default provisions that apply separately to each borrower. However, a default of Ameren Missouri or Ameren Illinois under the applicable credit agreement is also deemed to constitute a default of Ameren (parent) 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 $100 million in the aggregate (including under the other credit agreement). However, under the default provisions of the Credit Agreements, any default of Ameren (parent) under either credit agreement that results solely from a default of Ameren Missouri or Ameren Illinois does not result in a cross-default of Ameren (parent) under the other credit agreement. Further, the Credit Agreements default provisions provide that an Ameren (parent) default under either of the Credit Agreements does not constitute a default by Ameren Missouri or Ameren Illinois.

None of the 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 the Credit Agreements at December 31, 2018.

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 (parent) 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 utility 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 utility money pool for the year ended December 31, 2018, was 2.10% (2017 – 1.19%).

See Note 13 – Related-party Transactions for the amount of interest income and expense from the utility money pool agreement recorded by the Ameren Companies for the years ended December 31, 2018, 2017, and 2016.

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, 2018 and 2017:



	2018			2017
Ameren (Parent):
2.70% Senior unsecured notes due 2020	$	350		$	350
3.65% Senior unsecured notes due 2026	350			350
Total long-term debt, gross	700			700
Less: Unamortized debt issuance costs	(3		)	(4		)
Long-term debt, net	$	697		$	696
Ameren Missouri:
Bonds and notes:
6.00% Senior secured notes due 2018(a)	—			179
5.10% Senior secured notes due 2018(a)	—			199
6.70% Senior secured notes due 2019(a)(b)	329			329
5.10% Senior secured notes due 2019(a)	244			244
5.00% Senior secured notes due 2020(a)	85			85
1992 Series bonds due 2022(c)(d)	47			47
3.50% Senior secured notes due 2024(a)	350			350
2.95% Senior secured notes due 2027(a)	400			400
5.45% First mortgage bonds due 2028(e)	(e)			(e)
1998 Series A bonds due 2033(c)(d)	60			60
1998 Series B bonds due 2033(c)(d)	50			50
1998 Series C bonds due 2033(c)(d)	50			50
5.50% Senior secured notes due 2034(a)	184			184
5.30% Senior secured notes due 2037(a)	300			300
8.45% Senior secured notes due 2039(a)(b)	350			350
3.90% Senior secured notes due 2042(a)(b)	485			485
3.65% Senior secured notes due 2045(a)	400			400
4.00% First mortgage bonds due 2048(f)	425			—
Finance obligations:
City of Bowling Green agreement (Peno Creek CT) due 2022(g)	30			36
Audrain County agreement (Audrain County CT) due 2023(g)	240			240
Total long-term debt, gross	4,029			3,988
Less: Unamortized discount and premium	(9		)	(7		)
Less: Unamortized debt issuance costs	(22		)	(20		)
Less: Maturities due within one year	(580		)	(384		)
Long-term debt, net	$	3,418		$	3,577



	2018			2017
Ameren Illinois:
Bonds and notes:
6.25% Senior secured notes due 2018(h)	—			144
9.75% Senior secured notes due 2018(h)	—			313
2.70% Senior secured notes due 2022(h)(i)	400			400
5.90% First mortgage bonds due 2023(j)	(j)			(j)
5.70% First mortgage bonds due 2024(k)	(k)			(k)
3.25% Senior secured notes due 2025(h)	300			300
6.125% Senior secured notes due 2028(h)	60			60
1993 Series B-1 Senior unsecured notes due 2028(d)	17			17
3.80% First mortgage bonds due 2028(l)	430			—
6.70% Senior secured notes due 2036(h)	61			61
6.70% Senior secured notes due 2036(m)	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)	490			490
3.70% First mortgage bonds due 2047(l)	500			500
4.50% First mortgage bonds due 2049(l)	500			—
Total long-term debt, gross	3,330			2,857
Less: Unamortized discount and premium	(3		)	(3		)
Less: Unamortized debt issuance costs	(31		)	(24		)
Less: Maturities due within one year	—			(457		)
Long-term debt, net	$	3,296		$	2,373
ATXI:
3.43% Senior notes due 2050(n)	$	450		$	450
Total long-term debt, gross	450			450
Less: Unamortized debt issuance costs	(2		)	(2		)
Long-term debt, net	$	448		$	448
Ameren consolidated long-term debt, net	$	7,859		$	7,094

(a)

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 2048 maturity of the 4.00% first mortgage bonds and the restrictions preventing a release date to occur that are attached to certain senior secured notes described in footnote (b) below, Ameren Missouri does not expect the first mortgage lien protection associated with these notes to fall away.

(b)

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 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.


(c)	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.


(d)	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 average interest rates for 2018 and 2017 were as follows:



	2018	2017
Ameren Missouri 1992 Series due 2022	2.37%	1.43%
Ameren Missouri 1998 Series A due 2033	2.76%	1.77%
Ameren Missouri 1998 Series B due 2033	2.79%	1.75%
Ameren Missouri 1998 Series C due 2033	2.83%	1.73%
Ameren Illinois 1993 Series B-1 due 2028	1.58%	1.08%


(e)	These bonds are first mortgage bonds issued by Ameren Missouri under the Ameren Missouri mortgage bond indenture. They are secured by substantially all Ameren Missouri property and franchises. Less than $1 million principal amount of the bonds remain outstanding.


(f)	These bonds are first mortgage bonds issued by Ameren Missouri under the Ameren Missouri bond indenture. They are secured by substantially all Ameren Missouri property and franchises.

(g)

Payments due related to these financing obligations are paid to a trustee, which is authorized to utilize the cash only to pay equal amounts due to Ameren Missouri under related bonds issued by the city/county and held by Ameren Missouri. The timing and amounts of payments due from Ameren Missouri under the agreements are equal to the timing and amount of bond service payments due to Ameren Missouri, resulting in no net cash flow. The balance of both the financing obligations and the related investments in debt securities, recorded in "Other Assets," was $270 million and $276 million, respectively, as of December 31, 2018 and 2017.

(h)

These notes are collaterally secured by first mortgage bonds issued by Ameren Illinois under its 1992 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 its 1992 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 2049 maturity date of the 4.50% first mortgage bonds, Ameren Illinois does not expect the first mortgage lien protection associated with these

notes to fall away.


(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.


(j)	These bonds are first mortgage bonds issued by Ameren Illinois under its 1933 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 first mortgage bonds issued by Ameren Illinois under its 1992 mortgage indenture. They are secured by substantially all property of the former IP and CIPS. The bonds are also backed by an insurance guarantee policy. Less than $1 million principal amount of the bonds remains outstanding.


(l)	These bonds are first mortgage bonds issued by Ameren Illinois under its 1992 mortgage indenture. They are secured by substantially all property of the former IP and CIPS.

(m)

These notes are collaterally secured by first mortgage bonds issued by Ameren Illinois under its 1933 mortgage indenture. They are secured by substantially all property of the former CILCO. The notes have a fall-away lien provision, and Ameren Illinois could cause these notes to become unsecured at any time by redeeming the 5.90% first mortgage bonds due 2023 (of which less than $1 million principal amount remains outstanding).


(n)	The following table presents the principal maturities schedule for the 3.43% senior notes due 2050:



Payment Date		Principal Payment
August 2022	$	49.5
August 2024		49.5
August 2027		49.5
August 2030		49.5
August 2032		49.5
August 2038		49.5
August 2043		76.5
August 2050		76.5
Total	$	450.0

The following table presents the aggregate maturities of long-term debt, including current maturities, for the Ameren Companies at December 31, 2018:



	Ameren (parent)(a)		Ameren Missouri(a)		Ameren Illinois(a)		ATXI(a)		Ameren Consolidated
2019	$	—	$	580	$	—	$	—	$	580
2020	350		92		—		—		442
2021	—		8		—		—		8
2022	—		55		400		50		505
2023	—		240		—		—		240
Thereafter	350		3,054		2,930		400		6,734
Total	$	700	$	4,029	$	3,330	$	450	$	8,509


(a)	Excludes unamortized discount, unamortized premium, and debt issuance costs of $3 million, $31 million, $34 million and $2 million at Ameren (parent), Ameren Missouri, Ameren Illinois and ATXI, 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 is 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, 2018 and 2017:



		Redemption Price (per share)			2018		2017
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 2018, Ameren issued a total of 1.2 million shares of common stock under its DRPlus and 401(k) plan, and received proceeds of $74 million. In addition, in 2018, Ameren issued 0.7 million shares of common stock valued at $35 million upon the vesting of stock-based compensation. Ameren did not issue any common stock in 2017 or 2016.

In October 2018, 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 issuable 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.

In December 2017, Ameren, Ameren Missouri, and Ameren Illinois filed a Form S-3 shelf registration statement with the SEC, registering the issuance of an indeterminate amount of certain types of securities. The registration statement became effective immediately upon filing and expires in December 2020.

Ameren filed a Form S-3 registration statement with the SEC in May 2017, authorizing the offering of 6 million additional shares of its common stock under the DRPlus, which expires in 2020. Shares of common stock sold under the DRPlus are, at Ameren’s option, newly issued shares, treasury shares, or shares purchased in the open market or in privately negotiated transactions. As of December 31, 2018 and 2017, the DRPlus participant funds of $1 million and $8 million, respectively, were reflected on Ameren’s consolidated balance sheets in “Other current assets.”

Ameren Missouri

In April 2018, Ameren Missouri issued $425 million of 4.00% first mortgage bonds due April 2048, with interest payable semiannually on April 1 and October 1 of each year, beginning October 1, 2018. Ameren Missouri received proceeds of $419 million, which were used to repay outstanding short-term debt, including short-term debt that Ameren Missouri incurred in connection with the repayment of $179 million of its 6.00% senior secured notes that matured April 1, 2018.

In August 2018, $199 million principal amount of Ameren Missouri’s 5.10% senior secured notes matured and were repaid with cash on hand.

In June 2017, Ameren Missouri issued $400 million of 2.95% senior secured notes due June 2027, with interest payable semiannually on June 15 and December 15 of each year, beginning December 15, 2017. Ameren Missouri received proceeds of $396 million, which were used, in conjunction with other available funds, to repay at maturity $425 million of Ameren Missouri’s 6.40% senior secured notes in June 2017.

For information on Ameren Missouri’s capital contributions, refer to Capital Contributions in Note 13 – Related-party Transactions.

Ameren Illinois

In May 2018, Ameren Illinois issued $430 million of 3.80% first mortgage bonds due May 2028, with interest payable semiannually on May 15 and November 15 of each year, beginning November 15, 2018. Ameren Illinois received proceeds of $427 million, which were used to repay outstanding short-term debt, including short-term debt that Ameren Illinois incurred in connection with the repayment of $144 million of its 6.25% senior secured notes that matured April 1, 2018.

In November 2018, Ameren Illinois issued $500 million of 4.50% first mortgage bonds due March 2049, with interest payable semiannually on March 15 and September 15 of each year, beginning March 15, 2019. Ameren Illinois received proceeds of $495 million, which were used to repay outstanding short-term debt, including short-term debt that Ameren Illinois incurred in connection with the repayment of $313 million of its 9.75% senior secured notes that matured November 15, 2018.

In November 2017, Ameren Illinois issued $500 million of 3.70% first mortgage bonds due December 2047, with interest payable semiannually on June 1 and December 1 of each year, beginning June 1, 2018. Ameren Illinois received proceeds of $492 million, which were used to repay outstanding short-term debt, including short-term debt that Ameren Illinois incurred in connection with the repayment of $250 million of its 6.125% senior secured notes that matured in November 2017.

For information on Ameren Illinois’ capital contributions, refer to Capital Contributions in Note 13 – Related-party Transactions.

ATXI

In June 2017, pursuant to a note purchase agreement, ATXI agreed to issue $450 million principal amount of 3.43% senior unsecured notes, due 2050, with interest payable semiannually on the last day of February and August of each year, beginning February 28, 2018, through a private placement offering exempt from registration under the Securities Act of 1933, as amended. ATXI issued $150 million principal amount of the notes in June 2017 and the remaining $300 million principal amount of the notes in August 2017. ATXI received proceeds of $449 million from the notes, which were used by ATXI to repay existing short-term and long-term affiliate debt.

Indenture Provisions and Other Covenants

Ameren Missouri’s and Ameren Illinois’ indentures 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, 2018, 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	5.5	$	4,688		>2.5	140.8	$	3,153
Ameren Illinois	>2.0	6.9	4,234		(d)	>1.5	3.2	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 $2,006 million and $985 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 its 1992 mortgage indenture.


(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 and ATXI may not pay any dividend on their respective stock unless, among other things, their respective earnings and earned surplus are sufficient to declare and pay a dividend after provisions are made for reasonable and proper reserves, or unless Ameren Illinois or ATXI 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, 2018, using the FERC-agreed upon calculation method, Ameren Illinois’ ratio of common stock equity to total capitalization was 51%.

ATXI’s note purchase agreement includes financial covenants that require ATXI not to permit at any time (1) debt to exceed 70% of total capitalization or (2) secured debt to exceed 10% of total assets.

At December 31, 2018, the Ameren Companies were in compliance with the provisions and covenants contained in their indentures and articles of incorporation, as applicable, and ATXI was in compliance with the provisions and covenants contained in its note purchase agreement. 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, 2018, none of the Ameren Companies had any significant off-balance-sheet financing arrangements, other than operating leases entered into in the ordinary course of business, variable interest entities, letters of credit, and Ameren (parent) guarantee arrangements on behalf of its subsidiaries. See Note 1 – Summary of Significant Accounting Policies for further detail concerning variable interest entities.

NOTE 6 – OTHER INCOME, NET

The following table presents the components of “Other Income, Net” in the Ameren Companies’ statements of income for the years ended December 31, 2018, 2017, and 2016:



	2018				2017			2016
Ameren:
Other Income, Net
Allowance for equity funds used during construction	$	36			$	24		$	27
Interest income on industrial development revenue bonds	26				26			27
Other interest income	7				8			13
Non-service cost components of net periodic benefit income	70			(a)	44			56
Other income	8				5			10
Donations	(33		)		(8		)	(16		)
Other expense	(12		)		(13		)	(16		)
Total Other Income, Net	$	102			$	86		$	101
Ameren Missouri:
Other Income, Net
Allowance for equity funds used during construction	$	27			$	21		$	23
Interest income on industrial development revenue bonds	26				26			27
Other interest income	2				1			1
Non-service cost components of net periodic benefit income	17			(a)	22			18
Other income	4				3			3
Donations	(14		)		(2		)	(4		)
Other expense	(6		)		(6		)	(6		)
Total Other Income, Net	$	56			$	65		$	62
Ameren Illinois:
Other Income, Net
Allowance for equity funds used during construction	$	9			$	3		$	4
Interest income	6				7			12
Non-service cost components of net periodic benefit income	34				10			24
Other income	3				2			6
Donations	(6		)		(5		)	(6		)
Other expense	(4		)		(5		)	(6		)
Total Other Income, Net	$	42			$	12		$	34


(a)	For the year ended December 31, 2018, the non-service cost components of net periodic benefit income were partially offset by a $17 million deferral due to a regulatory tracking mechanism for the difference between the level of such costs incurred by Ameren Missouri under GAAP and the level of such costs included in rates.

NOTE 7 – DERIVATIVE FINANCIAL INSTRUMENTS

We use derivatives to manage the risk of changes in market prices for natural gas and power, 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 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, 2018 and 2017. As of December 31, 2018, these contracts extended through October 2021, March 2023, and May 2032 for fuel oils, natural gas, and power, respectively.



	Quantity (in millions)
	2018			2017
Commodity	Ameren Missouri	Ameren Illinois	Ameren	Ameren Missouri	Ameren Illinois	Ameren
Fuel oils (in gallons)(a)	66	—	66	28	—	28
Natural gas (in mmbtu)	19	154	173	24	139	163
Power (in megawatthours)	1	8	9	3	9	12


(a)	Consists of ultra-low-sulfur diesel products.

All contracts considered to be derivative instruments are required to 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 the resulting gains or losses 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 liabilities in the period in which the change occurs. We believe derivative losses and gains deferred as regulatory assets and liabilities are probable of recovery, or refund, through future rates charged to customers. Regulatory assets and 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, 2018 and 2017, all contracts that met the definition of a derivative and were not eligible for the NPNS exception received regulatory deferral.

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, 2018 and 2017:



			2018					2017
Commodity	Balance Sheet Location		Ameren Missouri		Ameren Illinois		Ameren		Ameren Missouri		Ameren Illinois		Ameren
Fuel oils	Other current assets	$	3	$	—	$	3	$	5	$	—	$	5
	Other assets		5		—		5		2		—		2
Natural gas	Other current assets		—		1		1		—		—		—
	Other assets		—		2		2		1		—		1
Power	Other current assets		4		—		4		9		—		9
	Total assets	$	12	$	3	$	15	$	17	$	—	$	17
Fuel oils	Other current liabilities	$	4	$	—	$	4	$	—	$	—	$	—
	Other deferred credits and liabilities		9		—		9		—		—		—
Natural gas	Other current liabilities		4		8		12		5		12		17
	Other deferred credits and liabilities		1		6		7		3		10		13
Power	Other current liabilities		4		14		18		1		13		14
	Other deferred credits and liabilities		—		169		169		—		182		182
	Total liabilities	$	22	$	197	$	219	$	9	$	217	$	226

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; these contracts 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. 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 Ameren Companies elect to present the fair value amounts of derivative assets and derivative liabilities subject to an enforceable master netting arrangement or similar agreement at the gross amounts on the balance sheet. However, if the gross amounts recognized on

the balance sheet were netted with derivative instruments and cash collateral received or posted, the net amounts would not be materially different from the gross amounts at December 31, 2018 and 2017.

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 calculated on a gross basis, which include affiliate exposure not eliminated at the consolidated Ameren level. As of December 31, 2018, if counterparty groups were to fail completely to perform on contracts, the Ameren Companies’ 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 our credit ratings were downgraded below investment grade, or if a counterparty with reasonable grounds for uncertainty regarding our ability to satisfy an obligation requested adequate assurance of performance, additional collateral postings might be required. The following table presents, as of December 31, 2018, 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, 2018, 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)
Ameren Missouri	$	76	$	4	$	64
Ameren Illinois	37		—		30
Ameren	$	113	$	4	$	94


(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 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 (quoted prices in active markets for identical assets or liabilities): 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.

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 (significant other observable inputs): 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 United States Treasury and agency securities, corporate bonds and other fixed-income 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.

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 bid/ask spreads to the midpoints. 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 midpoints. The value of natural gas derivative contracts is based upon exchange closing prices without significant unobservable adjustments. The value of power derivative contracts is based upon exchange closing prices or 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 (significant other unobservable inputs): 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, such as certain internal assumptions, quotes or prices from outside sources not supported by a liquid market, or escalation rates. Our development and corroboration process entails reasonableness reviews and an evaluation of all sources 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.

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 material gains or losses related to valuation adjustments for counterparty default risk were recorded at Ameren, Ameren Missouri, or Ameren Illinois in 2018, 2017, or 2016. At December 31, 2018 and 2017, 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, 2018 and 2017:



		December 31, 2018									December 31, 2017
		Level 1		Level 2		Level 3		Total			Level 1		Level 2		Level 3		Total
Assets:
Ameren
	Derivative assets – commodity contracts(a):
	Fuel oils	$	1	$	—	$	7	$	8		$	4	$	—	$	3	$	7
	Natural gas	—		2		1		3			—		—		1		1
	Power	—		1		3		4			—		1		8		9
	Total derivative assets – commodity contracts	$	1	$	3	$	11	$	15		$	4	$	1	$	12	$	17
	Nuclear decommissioning trust fund:
	Equity securities:
	U.S. large capitalization	$	427	$	—	$	—	$	427		$	468	$	—	$	—	$	468
	Debt securities:
	U.S. Treasury and agency securities	—		148		—		148			—		125		—		125
	Corporate bonds	—		72		—		72			—		82		—		82
	Other	—		32		—		32			—		25		—		25
	Total nuclear decommissioning trust fund	$	427	$	252	$	—	$	679	(b)	$	468	$	232	$	—	$	700	(b)
	Total Ameren	$	428	$	255	$	11	$	694		$	472	$	233	$	12	$	717
Ameren Missouri
	Derivative assets – commodity contracts(a):
	Fuel oils	$	1	$	—	$	7	$	8		$	4	$	—	$	3	$	7
	Natural gas	—		—		—		—			—		—		1		1
	Power	—		1		3		4			—		1		8		9
	Total derivative assets – commodity contracts	$	1	$	1	$	10	$	12		$	4	$	1	$	12	$	17
	Nuclear decommissioning trust fund:
	Equity securities:
	U.S. large capitalization	$	427	$	—	$	—	$	427		$	468	$	—	$	—	$	468
	Debt securities:
	U.S. Treasury and agency securities	—		148		—		148			—		125		—		125
	Corporate bonds	—		72		—		72			—		82		—		82
	Other	—		32		—		32			—		25		—		25
	Total nuclear decommissioning trust fund	$	427	$	252	$	—	$	679	(b)	$	468	$	232	$	—	$	700	(b)
	Total Ameren Missouri	$	428	$	253	$	10	$	691		$	472	$	233	$	12	$	717
Ameren Illinois
	Derivative assets – commodity contracts(a):
	Natural gas	$	—	$	2	$	1	$	3		$	—	$	—	$	—	$	—
Liabilities:
Ameren
	Derivative liabilities – commodity contracts(a):
	Fuel oils	$	2	$	—	$	11	$	13		$	—	$	—	$	—	$	—
	Natural gas	—		15		4		19			1		25		4		30
	Power	—		1		186		187			—		—		196		196
	Total Ameren	$	2	$	16	$	201	$	219		$	1	$	25	$	200	$	226
Ameren Missouri
	Derivative liabilities – commodity contracts(a):
	Fuel oils	$	2	$	—	$	11	$	13		$	—	$	—	$	—	$	—
	Natural gas	—		5		—		5			—		7		1		8
	Power	—		1		3		4			—		—		1		1
	Total Ameren Missouri	$	2	$	6	$	14	$	22		$	—	$	7	$	2	$	9
Ameren Illinois
	Derivative liabilities – commodity contracts(a):
	Natural gas	$	—	$	10	$	4	$	14		$	1	$	18	$	3	$	22
	Power	—		—		183		183			—		—		195		195
	Total Ameren Illinois	$	—	$	10	$	187	$	197		$	1	$	18	$	198	$	217


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


(b)	Balance excludes $5 million and $4 million of cash and cash equivalents, receivables, payables, and accrued income, net for December 31, 2018 and 2017, respectively.

See Note 10 – Retirement Benefits for tables that set forth, by level within the fair value hierarchy, Ameren’s pension and postretirement plan assets as of December 31, 2018 and 2017.

Level 3 fuel oils and natural gas derivative contract assets and liabilities measured at fair value on a recurring basis were immaterial for all periods presented. The following table presents the fair value reconciliation of Level 3 power derivative contract assets and liabilities measured at fair value on a recurring basis for the years ended December 31, 2018 and 2017:



	2018									2017
	Ameren Missouri			Ameren Illinois			Ameren			Ameren Missouri			Ameren Illinois			Ameren
Beginning balance at January 1	$	7		$	(195	)	$	(188	)	$	7		$	(185	)	$	(178	)
Realized and unrealized gains (losses) included in regulatory assets/liabilities	(6		)	—			(6		)	(4		)	(21		)	(25		)
Purchases	5			—			5			14			—			14
Sales	—			—			—			1			—			1
Settlements	(5		)	12			7			(11		)	11			—
Transfers out of Level 3	(1		)	—			(1		)	—			—			—
Ending balance at December 31	$	—		$	(183	)	$	(183	)	$	7		$	(195	)	$	(188	)
Change in unrealized gains (losses) related to assets/liabilities held at December 31	$	(1	)	$	(2	)	$	(3	)	$	—		$	(22	)	$	(22	)

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. For the years ended December 31, 2018 and 2017, there were no material transfers between Level 1 and Level 2, Level 1 and Level 3, or Level 2 and Level 3 related to derivative commodity contracts.

All gains or losses related to our Level 3 derivative commodity contracts are expected to be recovered or returned through customer rates; therefore, there is no impact to net income resulting from changes in the fair value of these instruments.

The following table describes the valuation techniques and significant unobservable inputs utilized for the fair value of our Level 3 power derivative contract assets and liabilities as of December 31, 2018 and 2017:



		Fair Value(a)								Weighted
	Commodity	Assets		Liabilities			Valuation Technique(s)	Unobservable Input	Range	Average
2018	Power(b)	$	3	$	(186	)	Discounted cash flow	Average forward peak and off-peak pricing – forwards/swaps($/MWh)(c)	23 – 39	28
								Nodal basis($/MWh)(c)	(9) – 0	(2)
							Fundamental energy production model	Estimated future natural gas prices($/mmbtu)(c)	3 – 4	3
								Escalation rate(%)(c)(d)	4 – 5	4
2017	Power(b)	$	8	$	(196	)	Discounted cash flow	Average forward peak and off-peak pricing – forwards/swaps($/MWh)(c)	24 – 46	28
								Nodal basis($/MWh)(c)	(10) – 0	(2)
							Fundamental energy production model	Estimated future natural gas prices($/mmbtu)(c)	3 – 4	3
								Escalation rate(%)(c)(d)	5	5

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


(b)	Power valuations use visible third-party pricing evaluated by month for peak and off-peak demand through 2022 and 2021 for December 31, 2018 and 2017, respectively. Valuations beyond 2022 and 2021 for December 31, 2018 and 2017, respectively, use fundamentally modeled pricing by month for peak and off-peak demand.


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


(d)	Escalation rate applies to power prices in 2031 and beyond.

The following table sets forth, by level within the fair value hierarchy, the carrying amount and fair value of financial assets and liabilities disclosed, but not carried, at fair value as of December 31, 2018 and 2017:



	December 31, 2018
	Carrying Amount			Fair Value
		Level 1			Level 2		Level 3		Total
Ameren:
Cash, cash equivalents, and restricted cash	$	107		$	107	$	—	$	—		$	107
Investments in held-to-maturity debt securities(a)	270			—		270		—			270
Short-term debt	597			—		597		—			597
Long-term debt (including current portion)(a)	8,439		(b)	—		8,240		429		(c)	8,669
Ameren Missouri:
Cash, cash equivalents, and restricted cash	$	8		$	8	$	—	$	—		$	8
Investments in held-to-maturity debt securities(a)	270			—		270		—			270
Short-term debt	55			—		55		—			55
Long-term debt (including current portion)(a)	3,998		(b)	—		4,156		—			4,156
Ameren Illinois:
Cash, cash equivalents, and restricted cash	$	80		$	80	$	—	$	—		$	80
Short-term debt	72			—		72		—			72
Long-term debt (including current portion)	3,296		(b)	—		3,391		—			3,391
	December 31, 2017
Ameren:
Cash, cash equivalents, and restricted cash	$	68		$	68	$	—	$	—		$	68
Investments in held-to-maturity debt securities(a)	276			—		276		—			276
Short-term debt	484			—		484		—			484
Long-term debt (including current portion)(a)	7,935		(b)	—		8,531		—			8,531
Ameren Missouri:
Cash, cash equivalents, and restricted cash	$	7		$	7	$	—	$	—		$	7
Investments in held-to-maturity debt securities(a)	276			—		276		—			276
Short-term debt	39			—		39		—			39
Long-term debt (including current portion)(a)	3,961		(b)	—		4,348		—			4,348
Ameren Illinois:
Cash, cash equivalents, and restricted cash	$	41		$	41	$	—	$	—		$	41
Short-term debt	62			—		62		—			62
Long-term debt (including current portion)	2,830		(b)	—		3,028		—			3,028

(a)

Ameren and Ameren Missouri have investments in industrial development revenue bonds, classified as held-to-maturity and recorded in “Other Assets,” that are equal to the finance obligations for the Peno Creek and Audrain CT energy centers. As of December 31, 2018 and 2017, the carrying amount of both the investments in industrial development revenue bonds and the finance obligations approximated fair value.

(b)

Included unamortized debt issuance costs, which were excluded from the fair value measurement, of $58 million, $22 million, and $31 million for Ameren, Ameren Missouri, and Ameren Illinois, respectively, as of December 31, 2018. Included unamortized debt issuance costs, which were excluded from the fair value measurement, of $50 million, $20 million, and $24 million for Ameren, Ameren Missouri, and Ameren Illinois, respectively, as of December 31, 2017.


(c)	The Level 3 fair value amount consists of ATXI’s senior unsecured notes. In the first quarter of 2018, the amount was transferred to Level 3 because inputs to the valuation model became unobservable during the period.

NOTE 9 – CALLAWAY ENERGY CENTER

Spent Nuclear Fuel

Under the NWPA, the DOE is responsible for disposing of spent nuclear fuel from the Callaway energy center and other commercial nuclear energy centers. As required by the NWPA, Ameren Missouri and other utilities have entered into standard contracts with the DOE, which stated that the DOE would begin to dispose of spent nuclear fuel by 1998. However, the DOE has failed to fulfill its disposal obligations, and Ameren Missouri and other nuclear energy center owners sued the DOE to recover costs incurred for ongoing storage of their spent fuel. Ameren Missouri’s lawsuit against the DOE resulted in a settlement agreement that provides for annual reimbursement of additional spent fuel storage and related costs. Ameren Missouri received reimbursements from the DOE of $11 million, $3 million, and $24 million in 2018, 2017, and 2016, respectively. Ameren Missouri will continue to apply for reimbursement from the DOE for allowable costs associated with the ongoing storage of spent fuel. 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.

Decommissioning

Electric 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. An updated cost study and funding analysis was filed with the MoPSC in September 2017 and reflected within the ARO. In January 2018, the MoPSC approved no change in electric rates for decommissioning costs consistent with Ameren Missouri’s updated cost study and funding analysis.

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. If the assumed return on trust assets is not earned, Ameren Missouri believes that it is probable that any such earnings deficiency will be recovered in rates.

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, 2018 and 2017. 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, 2018, 2017, and 2016:



	2018		2017		2016
Proceeds from sales and maturities	$	299	$	305	$	304
Gross realized gains	18		13		7
Gross realized losses	5		5		4

Net realized and unrealized gains and losses are deferred and are currently reflected in the regulatory liability related to AROs 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, 2018 and 2017:



Security Type	Cost		Gross Unrealized Gain			Gross Unrealized Loss	Fair Value
2018
Debt securities	$	253	$	3	$	4	$	252
Equity securities	162		277			12	427
Cash and cash equivalents	3		—			—	3
Other(a)	2		—			—	2
Total	$	420	$	280	$	16	$	684
2017
Debt securities	$	228	$	5	$	1	$	232
Equity securities	155		318			5	468
Cash and cash equivalents	2		—			—	2
Other(a)	2		—			—	2
Total	$	387	$	323	$	6	$	704


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

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, 2018:



	Cost		Fair Value
Less than 5 years	$	140	$	140
5 years to 10 years	48		47
Due after 10 years	65		65
Total	$	253	$	252

There are unrealized losses relating to certain available-for-sale investments included in the nuclear decommissioning trust fund, deferred within the regulatory liability as discussed above. Decommissioning will not occur until Ameren Missouri’s nuclear energy center is retired. The Callaway energy center’s operating license expires in 2044.

Insurance

The following table presents insurance coverage at Ameren Missouri’s Callaway energy center at December 31, 2018. The property coverage and the nuclear liability coverage renewal dates are April 1 and January 1, respectively, of each year. Both coverages were renewed in 2018.



Type and Source of Coverage	Maximum Coverages			Maximum Assessments for Single Incidents
Public liability and nuclear worker liability:
American Nuclear Insurers	$	450		$	—
Pool participation	13,623		(a)	138		(b)
	$	14,073	(c)	$	138
Property damage:
NEIL and EMANI	$	3,200	(d)	$	27	(e)
Replacement power:
NEIL	$	490	(f)	$	7	(e)


(a)	Provided through mandatory participation in an industrywide retrospective premium assessment program. The maximum coverage available is dependent on the number of United States commercial reactors participating in the program.


(b)	Retrospective premium under the Price-Anderson Act. This is subject to retrospective assessment with respect to a covered loss in excess of $450 million in the event of an incident at any licensed United States commercial reactor, payable at $21 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. This limit is subject to change to account for the effects of inflation and changes in the number of licensed reactors.


(d)	NEIL provides $2.7 billion in property damage, stabilization, decontamination, and premature decommissioning insurance for radiation events and $2.3 billion in property damage insurance for nonradiation events. EMANI provides $490 million in property damage insurance for both radiation and nonradiation events.


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


(f)	Provides replacement power cost insurance in the event of a prolonged accidental outage. Weekly indemnity up to $4.5 million for 52 weeks, which commences after the first 12 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 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 November 2018. 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 insured by NEIL are subject to industrywide aggregates, such that terrorist acts against one or more commercial nuclear power plants within a stated time period would be treated as a single event, and the owners of the nuclear power plants would share the limit of liability. NEIL policies have an aggregate limit of $3.2 billion within a 12-month period for radiation events, or $1.8 billion for events not involving radiation contamination. The EMANI policies are not subject to industrywide aggregates in the event of terrorist attacks on nuclear facilities.

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, or liquidity.

NOTE 10 – 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 has defined benefit pension and postretirement benefit plans covering

substantially all of its union employees. Ameren has 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 plan is the Ameren Retiree Welfare Benefit Plan. Only Ameren subsidiaries participate in the plans listed above.

Ameren’s unfunded obligation under its pension and other postretirement benefit plans was $481 million and $551 million as of December 31, 2018 and 2017, 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 decrease in the unfunded obligation during 2018 was the result of a 75 basis point increase in the pension and other postretirement benefit plan discount rates used to determine the present value of the obligation offset by a decrease in the return on plan assets of the pension and postretirement trusts. The decrease in the unfunded obligation also resulted in a decrease to “Regulatory assets” on Ameren’s, Ameren Missouri’s, and Ameren Illinois’ balance sheets.

The following table presents the net benefit liability recorded on the balance sheets of each of the Ameren Companies as of December 31, 2018 and 2017:



	2018		2017
Ameren(a)	$	481	$	551
Ameren Missouri	229		215
Ameren Illinois(a)	120		213


(a)	Assets associated with other postretirement benefits are recorded in “Other assets” on the balance sheet.

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. The following table presents the funded status of Ameren’s pension and postretirement benefit plans as of December 31, 2018 and 2017. It also provides the amounts included in regulatory assets and accumulated OCI at December 31, 2018 and 2017, that have not been recognized in net periodic benefit costs.



	2018						2017
	Pension Benefits				Postretirement Benefits		Pension Benefits				Postretirement Benefits
Accumulated benefit obligation at end of year	$	4,258		$	(a)		$	4,577		$	(a)
Change in benefit obligation:
Net benefit obligation at beginning of year	$	4,827		$	1,240		$	4,518		$	1,170
Service cost	100				21		93				21
Interest cost	169				40		179				47
Plan amendments	—				(49	)	—				—
Participant contributions	—				9		—				8
Actuarial (gain) loss	(401		)		(163	)	255				53
Benefits paid	(236		)		(64	)	(218		)		(59	)
Net benefit obligation at end of year	4,459				1,034		4,827				1,240
Change in plan assets:
Fair value of plan assets at beginning of year	4,293				1,223		3,813				1,101
Actual return on plan assets	(218		)		(57	)	634				171
Employer contributions	60				2		64				2
Participant contributions	—				9		—				8
Benefits paid	(236		)		(64	)	(218		)		(59	)
Fair value of plan assets at end of year	3,899				1,113		4,293				1,223
Funded status – deficiency (surplus)	560				(79	)	534				17
Accrued benefit cost (asset) at December 31	$	560		$	(79	)	$	534		$	17
Amounts recognized in the balance sheet consist of:
Noncurrent asset(b)	$	—		$	(79	)	$	—		$	—
Current liability(c)	2				—		3				3
Noncurrent liability	558				—		531				14
Net liability (asset) recognized	$	560		$	(79	)	$	534		$	17
Amounts recognized in regulatory assets consist of:
Net actuarial (gain) loss	$	393		$	(91	)	$	374		$	(69	)
Prior service credit	(2		)		(48	)	(3		)		(3	)
Amounts (pretax) recognized in accumulated OCI consist of:
Net actuarial loss	35				3		30				2
Total	$	426		$	(136	)	$	401		$	(70	)


(a)	Not applicable.


(b)	Included in “Other assets” on Ameren’s consolidated balance sheet.


(c)	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, 2018 and 2017:



	Pension Benefits				Postretirement Benefits
	2018		2017		2018		2017
Discount rate at measurement date	4.25	%	3.50	%	4.25	%	3.50	%
Increase in future compensation	3.50		3.50		3.50		3.50
Medical cost trend rate (initial)(a)	(b)		(b)		5.00		5.00
Medical cost trend rate (ultimate)(a)	(b)		(b)		5.00		5.00


(a)	Initial and ultimate medical cost trend rate for certain Medicare-eligible participants is 3.00%.


(b)	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 nearly 600 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 2018, Ameren adopted the Society of Actuaries 2018 Mortality Improvement

Scale. The updated scale assumes a lower rate of mortality improvement as compared to the 2017 Mortality Improvement Scale that Ameren used in 2017, 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 cost or the legally required minimum contribution. Based on its assumptions at December 31, 2018, its investment performance in 2018, and its pension funding policy, Ameren expects to make annual contributions of approximately $20 million to $70 million in each of the next five years, with aggregate estimated contributions of $200 million. Ameren Missouri and Ameren Illinois estimate that their portion of the future funding requirements will be 30% and 60%, respectively. These estimates 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 2018, 2017, and 2016:



	Pension Benefits						Postretirement Benefits
	2018		2017		2016		2018		2017		2016
Ameren Missouri	$	18	$	19	$	21	$	1	$	1	$	1
Ameren Illinois	35		37		30		1		1		1
Other	7		8		6		—		—		—
Ameren	$	60	$	64	$	57	$	2	$	2	$	2

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 2019. No plan assets are expected to be returned to Ameren during 2019.

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 2019 and our pension and postretirement plans’ asset categories as of December 31, 2018 and 2017:



Asset Category	Target Allocation 2019	Percentage of Plan Assets at December 31,
2018		2017
Pension Plan:
Cash and cash equivalents	0% – 5%	1	%	1	%
Equity securities:
U.S. large-capitalization	21% – 31%	24	%	34	%
U.S. small- and mid-capitalization	3% – 13%	7	%	9	%
International	9% – 19%	13	%	14	%
Global	3% – 13%	8	%	—	%
Total equity	51% – 61%	52	%	57	%
Debt securities	35% – 45%	42	%	37	%
Real estate	0% – 9%	5	%	5	%
Private equity	0% – 5%	(a)		(a)
Total		100	%	100	%
Postretirement Plans:
Cash and cash equivalents	0% – 7%	2	%	2	%
Equity securities:
U.S. large-capitalization	34% – 44%	40	%	41	%
U.S. small- and mid-capitalization	2% – 12%	7	%	8	%
International	9% – 19%	13	%	14	%
Total equity	55% – 65%	60	%	63	%
Debt securities	33% – 43%	38	%	35	%
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, global, 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 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. Additionally, Ameren’s investment committee allows investment managers to use derivatives, such as index futures, 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, 2018. 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 measurement date or, if that is not a business day, on the last business day before that date. Securities traded in over-the-counter markets are valued by quoted market prices, broker or dealer quotations, or alternative pricing sources with reasonable levels of price transparency. Investments measured under NAV as a practical expedient are based on the fair values of the underlying assets provided by the funds and their administrators. The fair value of real estate investments is based on NAV; it is determined by annual appraisal reports prepared by an independent real estate appraiser. Investments measured at NAV often provide for daily, monthly, or quarterly redemptions with 60 or less days of notice depending on the fund. For some funds, redemption may also require approval from the fund’s board of directors. 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 following table sets forth, by level within the fair value hierarchy discussed in Note 8 – Fair Value Measurements, the pension plans’ assets measured at fair value as of December 31, 2018:



	Quoted Prices in Active Markets for Identified Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Other Unobservable Inputs (Level 3)		Measured at NAV		Total
Cash and cash equivalents	$	—	$	—	$	—	$	41	$	41
Equity securities:
U.S. large-capitalization	—		—		—		955		955
U.S. small- and mid-capitalization	272		—		—		—		272
International	224		—		—		298		522
Global	—		—		—		321		321
Debt securities:
Corporate bonds	—		701		—		19		720
Municipal bonds	—		87		—		—		87
U.S. Treasury and agency securities	—		891		—		—		891
Other	1		11		—		—		12
Real estate	—		—		—		202		202
Private equity	—		—		—		3		3
Total	$	497	$	1,690	$	—	$	1,839	$	4,026
Less: Medical benefit assets at December 31(a)									(144		)
Plus: Net receivables at December 31(b)									17
Fair value of pension plans’ assets at December 31									$	3,899


(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 plans’ assets measured at fair value as of December 31, 2017:



	Quoted Prices in Active Markets for Identified Assets or Liabilities (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Other Unobservable Inputs (Level 3)		Measured at NAV		Total
Cash and cash equivalents	$	—	$	—	$	—	$	25	$	25
Equity securities:
U.S. large-capitalization	—		—		—		1,523		1,523
U.S. small- and mid-capitalization	379		—		—		—		379
International	179		—		—		450		629
Debt securities:
Corporate bonds	—		726		—		15		741
Municipal bonds	—		91		—		—		91
U.S. Treasury and agency securities	8		816		—		—		824
Other	—		7		—		—		7
Real estate	—		—		—		196		196
Private equity	—		—		—		4		4
Total	$	566	$	1,640	$	—	$	2,213	$	4,419
Less: Medical benefit assets at December 31(a)									(153		)
Plus: Net receivables at December 31(b)									27
Fair value of pension plans’ assets at December 31									$	4,293


(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 postretirement benefit plans’ assets measured at fair value as of December 31, 2018:



	Quoted Prices in Active Markets for Identified Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Other Unobservable Inputs (Level 3)		Measured at NAV		Total
Cash and cash equivalents	$	32	$	—	$	—	$	—	$	32
Equity securities:
U.S. large-capitalization	297		—		—		89		386
U.S. small- and mid-capitalization	63		—		—		—		63
International	45		—		—		84		129
Other	—		12		—		—		12
Debt securities:
Corporate bonds	—		144		—		—		144
Municipal bonds	—		107		—		—		107
U.S. Treasury and agency securities	—		62		—		—		62
Other	—		7		—		34		41
Total	$	437	$	332	$	—	$	207	$	976
Plus: Medical benefit assets at December 31(a)									144
Less: Net payables at December 31(b)									(7		)
Fair value of postretirement benefit plans’ assets at December 31									$	1,113


(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.



	Quoted Prices in Active Markets for Identified Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Other Unobservable Inputs (Level 3)		Measured at NAV		Total
Cash and cash equivalents	$	44	$	—	$	—	$	—	$	44
Equity securities:
U.S. large-capitalization	332		—		—		110		442
U.S. small- and mid-capitalization	80		—		—		—		80
International	53		—		—		101		154
Other	—		8		—		—		8
Debt securities:
Corporate bonds	—		144		—		—		144
Municipal bonds	—		110		—		—		110
U.S. Treasury and agency securities	—		76		—		—		76
Other	—		4		—		34		38
Total	$	509	$	342	$	—	$	245	$	1,096
Plus: Medical benefit assets at December 31(a)									153
Less: Net payables at December 31(b)									(26		)
Fair value of postretirement benefit plans’ assets at December 31									$	1,223


(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.

Net Periodic Benefit Cost

In March 2017, the FASB issued authoritative guidance that requires an entity to report, including on a retrospective basis, the non-service cost or income components of net periodic benefit cost separately from the service cost component and outside of operating income. The Ameren Companies adopted this guidance, effective January 1, 2018, and as a result, $44 million, $22 million, and $10 million of net benefit income has been retrospectively reclassified from “Operating Expenses – Other operations and maintenance” to “Other Income, Net” on Ameren's, Ameren Missouri’s, and Ameren Illinois’ respective statements of income for the year ended December 31, 2017. Net benefit income of $56 million, $18 million, and $24 million has been similarly retrospectively reclassified on Ameren’s, Ameren Missouri’s, and Ameren Illinois’ respective statements of income for the year ended December 31, 2016.

The guidance also requires an entity to capitalize only the service cost component as part of an asset, such as inventory or property, plant, and equipment, on a prospective basis. Previously all of the net benefit cost components were eligible for capitalization. This change in the capitalization of net benefit costs is not expected to affect our ability to recover total net benefit cost through customer rates.

The following table presents the components of the net periodic benefit cost of Ameren’s pension and postretirement benefit plans during 2018, 2017, and 2016:



	Pension Benefits			Postretirement Benefits
2018
Service cost(a)	$	100		$	21
Non-service cost components:
Interest cost	169			40
Expected return on plan assets	(276		)	(77		)
Amortization of:
Prior service credit	(1		)	(4		)
Actuarial (gain) loss	68			(6		)
Total non-service cost components(b)	$	(40	)	$	(47	)
Net periodic benefit cost (income)	$	60		$	(26	)
2017
Service cost(a)	$	93		$	21
Non-service cost components:
Interest cost	179			47
Expected return on plan assets	(262		)	(75		)
Amortization of:
Prior service credit	(1		)	(5		)
Actuarial (gain) loss	55			(6		)
Total non-service cost components(b)	$	(29	)	$	(39	)
Net periodic benefit cost (income)	$	64		$	(18	)
2016
Service cost(a)	$	81		$	19
Non-service cost components:
Interest cost	185			50
Expected return on plan assets	(253		)	(72		)
Amortization of:
Prior service credit	(1		)	(5		)
Actuarial (gain) loss	32			(11		)
Total non-service cost components(b)	$	(37	)	$	(38	)
Net periodic benefit cost (income)	$	44		$	(19	)

(a) Service cost, net of capitalization, is reflected in “Operating Expenses - Other operations and maintenance” on Ameren’s statement of income.


(b)	2018 amounts and the non-capitalized portion of 2017 and 2016’s non-service cost components, as discussed above, are reflected in “Other Income, Net” on Ameren’s statement of income. See Note 5 - Other Income, Net for additional information.

The estimated amounts that will be amortized from regulatory assets and accumulated OCI into Ameren’s net periodic benefit cost in 2019 are as follows:



	Pension Benefits			Postretirement Benefits
Regulatory assets:
Prior service credit	$	(1	)	$	(5	)
Net actuarial (gain) loss	24			(15		)
Accumulated OCI:
Net actuarial loss	2			—
Total	$	25		$	(20	)

Prior service cost is amortized on a straight-line basis over the average future service of active participants benefiting under the plan amendment. Net actuarial gains or losses subject to amortization are 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 for the years ended December 31, 2018, 2017, and 2016:



	Pension Costs									Postretirement Costs
	2018			2017			2016			2018			2017			2016
Ameren Missouri(a)	$	22		$	24		$	26		$	(1	)	$	(4	)	$	(5	)
Ameren Illinois	39			41			22			(25		)	(14		)	(13		)
Other	(1		)	(1		)	(4		)	—			—			(1		)
Ameren	60			64			44			(26		)	(18		)	(19		)


(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 and the level of such costs included in customer rates.

The expected pension and postretirement benefit payments from qualified trust and company funds, which reflect expected future service, as of December 31, 2018, 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
2019	$	267	$	3	$	57	$	2
2020	272		3		59		2
2021	282		3		61		2
2022	285		3		62		2
2023	286		3		64		2
2024 – 2028	1,439		12		315		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, 2018, 2017, and 2016:



	Pension Benefits						Postretirement Benefits
	2018		2017		2016		2018		2017		2016
Discount rate at measurement date	3.50	%	4.00	%	4.50	%	3.50	%	4.00	%	4.50	%
Expected return on plan assets	7.00		7.00		7.00		7.00		7.00		7.00
Increase in future compensation	3.50		3.50		3.50		3.50		3.50		3.50
Medical cost trend rate (initial)(a)	(b)		(b)		(b)		5.00		5.00		5.00
Medical cost trend rate (ultimate)(a)	(b)		(b)		(b)		5.00		5.00		5.00


(a)	Initial and ultimate medical cost trend rate for certain Medicare-eligible participants is 3.00%.


(b)	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	$	(2	)	$	135	$	—		$	33
0.25% increase in salary scale	2			12		—			—
1.00% increase in annual medical trend	—			—		4			58
1.00% decrease in annual medical trend	—			—		(4		)	(58		)

Other

Ameren sponsors a 401(k) plan for eligible employees. The Ameren 401(k) plan covered all eligible Ameren employees at December 31, 2018. 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 each of the Ameren Companies for the years ended December 31, 2018, 2017, and 2016:



	2018		2017		2016
Ameren Missouri	$	17	$	16	$	16
Ameren Illinois	15		13		12
Other	1		1		1
Ameren	$	33	$	30	$	29

NOTE 11 – STOCK-BASED COMPENSATION

The 2014 Incentive Plan is Ameren’s long-term stock-based compensation plan for eligible employees and directors. The 2014 Incentive Plan provides for a maximum of 8 million common shares to be available for grant to eligible employees and directors. At December 31, 2018, there were 3.8 million common shares remaining for grant 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. Ameren used newly issued shares to fulfill its stock-based compensation obligations for 2018 and intends to use newly issued shares to fulfill its stock-based compensation obligations for 2019.

The following table summarizes Ameren’s nonvested performance share unit and restricted stock unit activity for the year ended December 31, 2018:



	Performance Share Units				Restricted Stock Units
	Share Units		Weighted-average Fair Value per Share Unit		Stock Units		Weighted-average Fair Value per Stock Unit
Nonvested at January 1, 2018(a)	895,489		$	52.28	—		$	—
Granted	316,875		62.88		187,273		57.66
Forfeitures	(65,106	)	51.11		(5,463	)	58.99
Vested and undistributed(b)	(288,404	)	53.63		(26,557	)	59.02
Vested and distributed	(176,043	)	52.88		—		—
Nonvested at December 31, 2018(c)	682,811		$	56.58	155,253		$	57.38


(a)	Does not include 712,572 undistributed vested performance share units.


(b)	Vested and undistributed units are awards that vested due to attainment of retirement eligibility by certain employees, but have not yet been distributed. For vested and undistributed performance share units, the number of shares issued for retirement-eligible employees will vary depending on actual performance over the three-year performance period.


(c)	Does not include 619,783 of vested and undistributed performance share units and 26,557 of vested and undistributed restricted stock units.

Performance Share Units

A performance 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 market conditions have been met and if the individual remains employed by Ameren through the required vesting period. The vesting period for share units awarded extends beyond the three-year performance period to the payout date, which is approximately 38 months after the grant date. In the event of a participant’s death or retirement at age 55 or older with five or more years of service, awards vest on a pro rata basis over the three-year performance 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 fair value of each share unit awarded under the 2014 Incentive Plan is based on Ameren’s closing common share price at December 31st of the year prior to the award year 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 1st of the award year. 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 include a three-year risk-free rate, volatility for the peer group, and Ameren’s attainment of a three-year average earnings per share threshold during the performance period. The following table presents the fair value of each share unit awarded under the 2014 Incentive Plan along with the significant assumptions used to calculate the fair value of each share unit for the years ended December 31, 2018, 2017, and 2016:



	2018	2017	2016
Fair value of share units awarded	$62.88	$59.16	$44.13
Ameren’s closing common share price at December 31 of the prior year	$61.69	$52.46	$43.23
Three-year risk-free rate	1.98%	1.47%	1.31%
Volatility range for the peer group(a)	15% – 23%	15% – 21%	15% – 20%


(a)	Based on a historical period that is equal to the remaining term of the performance period as of the grant date.

Restricted Stock Units

Restricted stock units vest and entitle an employee to receive shares of Ameren common stock (plus accumulated dividends) if the individual remains employed with Ameren through the payment date of the awards. Generally, in the event of a participant’s death or retirement at age 55 or older with five or more years of service, awards vest on a pro rata basis. The payout date of the awards is approximately 38 months after the grant date. The fair value of each restricted stock unit is determined by Ameren’s closing common share price on the grant date.

Stock-Based Compensation Expense

The following table presents the stock-based compensation expense for the years ended December 31, 2018, 2017, and 2016:



	2018		2017		2016
Ameren Missouri	$	4	$	4	$	4
Ameren Illinois	3		2		2
Other(a)	13		12		11
Ameren	20		18		17
Less income tax benefit	6		7		6
Stock-based compensation expense, net	$	14	$	11	$	11


(a)	Represents compensation expense of employees of Ameren Services. These amounts are not included in the Ameren Missouri and Ameren Illinois amounts above.

Ameren settled performance share units and restricted stock units of $54 million, $39 million, and $83 million for the years ended December 31, 2018, 2017, and 2016. There were no significant stock-based compensation costs capitalized during the years ended December 31, 2018, 2017, and 2016. As of December 31, 2018, total compensation cost of $29 million related to nonvested awards not yet recognized is expected to be recognized over a weighted-average period of 22 months.

Ameren realized income tax benefits for settled performance share units of $13 million, $15 million, and $31 million for the years ended December 31, 2018, 2017, and 2016.

NOTE 12 – INCOME TAXES

Federal Tax Reform

The TCJA was enacted on December 22, 2017. Substantially all of the provisions of the TCJA affecting the Ameren Companies, other than certain transition depreciation rules, are effective for taxable years beginning after December 31, 2017. The TCJA includes significant changes to the Internal Revenue Code, including amendments that significantly change the taxation of business entities and specific provisions related to regulated public utilities. The most significant change that affects the Ameren Companies is the reduction in the federal corporate statutory income tax rate from 35% to 21%. Specific provisions related to regulated public utilities generally allow for the continued deductibility of interest expense, the elimination of accelerated depreciation tax benefits from certain regulated utility capital investments acquired after September 27, 2017, and the continuation of certain rate normalization requirements related to the flow back of excess deferred taxes. Ameren (parent) is subject to provisions of the TCJA that limit the deductibility of interest expense, but such limitation did not affect Ameren in 2018.

In accordance with GAAP, the tax effects of changes in tax laws must be recognized in the period in which the law is enacted. GAAP also requires deferred tax assets and liabilities to be measured at the tax rate that is expected to apply when temporary differences are realized or settled. Thus, in December 2017, the Ameren Companies’ deferred taxes were revalued using the new tax rate. To the extent deferred tax balances are included in rate base, the revaluation of deferred taxes was deferred as a regulatory asset or liability on the balance sheet and will be collected from, or refunded, to customers. For deferred tax balances not included in rate base, the revaluation of deferred taxes was recorded as income tax expense. As of December 31, 2017, the Ameren Companies made reasonable estimates for the measurement and accounting of certain effects of the TCJA, which have been reflected in their financial statements. We recorded provisional estimates primarily related to depreciation transition rules and 2017 property, plant, and equipment, compensation, and pension-related deductions which would impact our revaluation of deferred taxes at December 31, 2017. The TCJA had the following provisional effects on the Ameren Companies for the year ended December 31, 2017:



	Ameren Missouri			Ameren Illinois			Other			Ameren
Increase (Decrease)
Accumulated deferred income taxes, net	$	(1,419	)	$	(871	)	$	37		$	(2,253	)
Income tax expense (benefit)	32			(5		)	127			154
Noncurrent regulatory assets	(89		)	(24		)	(1		)	(114		)
Noncurrent regulatory liabilities	1,362			842			89			2,293

During the year ended December 31, 2018, Ameren, Ameren Missouri, and Ameren Illinois updated their respective provisional estimates in accordance with SEC staff guidance and recorded $13 million, $4 million, and $4 million, respectively, of income tax expense, primarily due to the application of proposed IRS regulations on depreciation transition rules. The offsetting impact to Ameren’s, Ameren Missouri’s, and Ameren Illinois’ regulatory asset and regulatory liability balances was immaterial. As of December 31, 2018, Ameren, Ameren Missouri, and Ameren Illinois have completed their accounting for certain effects of the TCJA.

For our regulated operations, reductions in accumulated deferred income tax balances due to the reduction in the federal statutory corporate income tax rate to 21% will result in amounts previously collected from utility customers for these deferred taxes being refundable to those customers, generally through reductions in future rates. The TCJA includes provisions related to the IRS normalization rules that address the time period in which certain plant-related components of the excess deferred taxes are to be reflected in customer rates. This time period for the Ameren Companies is approximately 30 to 60 years. Other components of the excess deferred taxes will be reflected in customer rates as determined by our state and federal regulators, which could be a shorter time period than that applicable to certain plant-related components. See Note 2 – Rate and Regulatory Matters for information regarding the various proceedings for the TCJA impacts with our regulators.

Missouri Income Tax Rate

In 2018, legislation modifying Missouri tax law was enacted to decrease the state's corporate income tax rate from 6.25% to 4%, effective January 1, 2020. As a result, in 2018, Ameren’s and Ameren Missouri’s accumulated deferred tax balances were revalued, resulting in a net decrease of $122 million to their accumulated deferred tax liability, which was offset by a regulatory liability. Additionally, Ameren recorded an immaterial amount to income tax expense. As a result of its PISA election under Missouri Senate Bill 564, which prohibits a change in electric base rates prior to April 2020, Ameren Missouri anticipates that the effect of this tax decrease will be reflected in customer rates upon completion of its next regulatory rate review. Ameren (parent) and nonregistrant subsidiaries do not expect this income tax decrease to have a material impact on net income.

Illinois Income Tax Rate

In July 2017, Illinois enacted a law that increased the state’s corporate income tax rate from 7.75% to 9.5% as of July 1, 2017. The law made the increase in the state’s corporate income tax rate permanent. That rate was previously scheduled to go to 7.3% in 2025. In 2017, Ameren recorded an expense of $14 million at Ameren (parent) due to the revaluation of accumulated deferred taxes and the estimated state apportionment of such taxes. Beyond this expense, Ameren and Ameren Illinois do not expect this tax increase to have a material impact on their net income prospectively. The tax increase is not expected to materially affect the earnings of the Ameren Illinois Electric Distribution, the Ameren Transmission, or the Ameren Illinois Transmission segments, since these businesses operate under formula ratemaking frameworks. The tax increase unfavorably affected the 2017 net income of the Ameren Illinois Natural Gas segment by less than $1 million. In addition, in 2017, Ameren’s and Ameren Illinois’ accumulated deferred tax balances were revalued using the state’s new corporate income tax rate, which resulted in a net increase to the liability balances of $97 million and $79 million, respectively. These increased liabilities were offset by a regulatory asset, as well as income tax expense, as discussed above.

The following table presents the principal reasons for the difference between the effective income tax rate and the federal statutory corporate income tax rate for the years ended December 31, 2018, 2017, and 2016:



	Ameren Missouri		Ameren Illinois		Ameren
2018
Federal statutory corporate income tax rate:	21	%	21	%	21	%
Increases (decreases) from:
Amortization of excess deferred taxes	(4	)	(4	)	(4	)
Other depreciation differences	—		(1	)	—
Amortization of deferred investment tax credit	(1	)	—		(1	)
State tax	4		7		6
TCJA	1		1		1
Tax credits	(1	)	—		—
Other permanent items	—		—		(1	)
Effective income tax rate	20	%	24	%	22	%
2017
Federal statutory corporate income tax rate:	35	%	35	%	35	%
Increases (decreases) from:
Depreciation differences	1		(1	)	—
Amortization of deferred investment tax credit	(1	)	—		(1	)
State tax	4		6		6
TCJA	6		(1	)	14
Tax credits	(1	)	—		—
Other permanent items	—		(1	)	(2	)
Effective income tax rate	44	%	38	%	52	%
2016
Federal statutory corporate income tax rate:	35	%	35	%	35	%
Increases (decreases) from:
Depreciation differences	1		—		—
Amortization of deferred investment tax credit	(1	)	—		—
State tax	3		5		4
Stock-based compensation(a)	—		—		(2	)
Valuation allowance	—		—		1
Other permanent items	—		(2	)	(1	)
Effective income tax rate	38	%	38	%	37	%


(a)	Reflects the adoption of authoritative accounting guidance related to stock-based compensation, which resulted in the recognition of a $21 million income tax benefit in 2016.

The following table presents the components of income tax expense for the years ended December 31, 2018, 2017, and 2016:



	Ameren Missouri			Ameren Illinois			Other			Ameren
2018
Current taxes:
Federal	$	104		$	4		$	(118	)	$	(10	)
State	29			6			(12		)	23
Deferred taxes:
Federal	22			75			123			220
State	(2		)	28			23			49
Amortization of excess deferred taxes	(24		)	(15		)	(1		)	(40		)
Amortization of deferred investment tax credits	(5		)	—			—			(5		)
Total income tax expense	$	124		$	98		$	15		$	237
2017
Current taxes:
Federal	$	149		$	(34	)	$	(110	)	$	5
State	23			29			(20		)	32
Deferred taxes:
Federal	76			185			250			511
State	11			(13		)	36			34
Amortization of deferred investment tax credits	(5		)	(1		)	—			(6		)
Total income tax expense	$	254		$	166		$	156		$	576
2016
Current taxes:
Federal	$	31		$	(8	)	$	(24	)	$	(1	)
State	6			12			(21		)	(3		)
Deferred taxes:
Federal	161			117			21			299
State	23			37			32			92
Amortization of deferred investment tax credits	(5		)	—			—			(5		)
Total income tax expense	$	216		$	158		$	8		$	382

The following table presents the accumulated deferred income tax assets and liabilities recorded as a result of temporary differences at December 31, 2018 and 2017:



	Ameren Missouri			Ameren Illinois			Other			Ameren
2018
Accumulated deferred income taxes, net liability (asset):
Plant-related	$	2,010		$	1,345		$	179		$	3,534
Regulatory assets and liabilities, net	(343		)	(221		)	(25		)	(589		)
Deferred employee benefit costs	(58		)	(4		)	(64		)	(126		)
Tax carryforwards	(35		)	(26		)	(166		)	(227		)
Other	(40		)	25			46			31
Total net accumulated deferred income tax liabilities (assets)	$	1,534		$	1,119		$	(30	)	$	2,623
2017
Accumulated deferred income taxes, net liability (asset):
Plant-related	$	2,064		$	1,264		$	146		$	3,474
Regulatory assets and liabilities, net	(317		)	(206		)	(24		)	(547		)
Deferred employee benefit costs	(53		)	(17		)	(61		)	(131		)
Revenue requirement reconciliation adjustments	—			20			—			20
Tax carryforwards	(31		)	(43		)	(287		)	(361		)
Other	(13		)	3			61			51
Total net accumulated deferred income tax liabilities (assets)	$	1,650		$	1,021		$	(165	)	$	2,506

The following table presents the components of accumulated deferred income tax assets relating to net operating loss carryforwards, tax credit carryforwards, and charitable contribution carryforwards at December 31, 2018 and 2017:



	Ameren Missouri		Ameren Illinois		Other			Ameren
2018
Net operating loss carryforwards:
Federal(a)	$	—	$	23	$	55		$	78
State(a)	—		—		13			13
Total net operating loss carryforwards	$	—	$	23	$	68		$	91
Tax credit carryforwards:
Federal(b)	$	35	$	3	$	79		$	117
State(c)	—		—		10			10
Total tax credit carryforwards	$	35	$	3	$	89		$	127
Charitable contribution carryforwards(d)	$	—	$	—	$	14		$	14
Valuation allowance(e)	—		—		(5		)	(5		)
Total charitable contribution carryforwards	$	—	$	—	$	9		$	9
2017
Net operating loss carryforwards:
Federal	$	—	$	41	$	162		$	203
State	—		—		32			32
Total net operating loss carryforwards	$	—	$	41	$	194		$	235
Tax credit carryforwards:
Federal	$	31	$	2	$	80		$	113
State	—		—		7			7
Total tax credit carryforwards	$	31	$	2	$	87		$	120
Charitable contribution carryforwards	$	—	$	—	$	11		$	11
Valuation allowance	—		—		(5		)	(5		)
Total charitable contribution carryforwards	$	—	$	—	$	6		$	6


(a)	Will expire between 2034 and 2037. Any net operating loss carryforward generated after January 1, 2018, will not have an expiration date as a result of the TCJA.


(b)	Will expire between 2029 and 2037.


(c)	Will expire between 2019 and 2022.


(d)	Will expire between 2019 and 2023.


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

Uncertain Tax Positions

As of December 31, 2018 and 2017, the Ameren Companies did not record any uncertain tax positions.

The Internal Revenue Service is currently examining Ameren’s 2018 and 2017 income tax returns. 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 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. It will then be amortized over three years, beginning on the effective date of new rates established in the next electric regulatory rate review.

NOTE 13 – RELATED-PARTY TRANSACTIONS

In the normal course of business, Ameren Missouri and Ameren Illinois 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 Ameren’s subsidiaries are reported as affiliate transactions on their individual financial statements, but those transactions are eliminated in consolidation for Ameren’s consolidated 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, 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 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

Based on the outcome of IPA-administered procurement events, Ameren Missouri and Ameren Illinois have entered into energy product agreements by which Ameren Missouri agreed to sell, and Ameren Illinois agreed to purchase, a set amount of megawatthours at a predetermined price over a specified period of time. The following table presents the specified performance period, price, and amount of megawatthours included in the agreements:



IPA Procurement Event	Performance Period	MWh		Average Price per MWh
May 2014	January 2015 – February 2017	168,400	$	51
April 2015	June 2015 – June 2017	667,000		36
September 2015	November 2015 – May 2018	339,000		38
April 2016	June 2017 – September 2018	375,200		35
September 2016	May 2017 – September 2018	82,800		34
April 2017	March 2019 – May 2020	85,600		34
April 2018	June 2019 – September 2020	110,000		32

Collateral Postings

Under the terms of the Illinois energy product 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, 2018 and 2017, there were no collateral postings required of Ameren Missouri related to the Illinois energy product agreements.

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 with access to their facilities for administrative purposes and with use of other assets. The costs of the rent and facility services and other assets 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 receives transmission services from ATXI for its retail load in the AMIL pricing zone.

Electric Transmission Maintenance and Construction Agreements

ATXI entered into separate agreements with Ameren Missouri and Ameren Illinois in which Ameren Missouri or Ameren Illinois, as applicable, may perform certain maintenance and construction services related to ATXI’s electric transmission assets. The Ameren Missouri and Ameren Illinois agreements are effective from August 2017 through June 2019 and from August 2018 through July 2019, respectively.

Money Pool

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

Tax Allocation Agreement

See Note 1 – Summary of Significant Accounting Policies for a discussion of the tax allocation agreement. The following table presents the affiliate balances related to income taxes for Ameren Missouri and Ameren Illinois as of December 31, 2018 and 2017:



	2018				2017
	Ameren Missouri		Ameren Illinois		Ameren Missouri		Ameren Illinois
Income taxes payable to parent(a)	$	16	$	7	$	11	$	17
Income taxes receivable from parent(b)	—		6		—		—


(a)	Included in “Accounts payable – affiliates” on the balance sheet.


(b)	Included in “Accounts receivable – affiliates” on the balance sheet.

Capital Contributions

The following table presents cash capital contributions received from Ameren (parent) by Ameren Missouri and Ameren Illinois for the years ended December 31, 2018, 2017, and 2016:



	2018		2017		2016
Ameren Missouri(a)	$	45	$	30	$	44	(b)
Ameren Illinois	160		8		—


(a)	As a result of the tax allocation agreement.


(b)	Included a $38 million accrued capital contribution from 2015.

The following table presents the impact on Ameren Missouri and Ameren Illinois of related-party transactions for the years ended December 31, 2018, 2017, and 2016. 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	2018	$	11	$	(a)
with Ameren Illinois		2017		23		(a)
		2016		28		(a)
Ameren Missouri and Ameren Illinois	Operating Revenues	2018		22		3
rent and facility services		2017		26		4
		2016		25		5
Ameren Missouri and Ameren Illinois miscellaneous	Operating Revenues	2018		1		1
support services and services provided to ATXI		2017		(b)		1
		2016		1		(b)
Total Operating Revenues		2018	$	34	$	4
		2017		49		5
		2016		54		5
Ameren Illinois power supply	Purchased Power	2018	$	(a)	$	11
agreements with Ameren Missouri		2017		(a)		23
		2016		(a)		28
Ameren Illinois transmission	Purchased Power	2018		(a)		1
services from ATXI		2017		(a)		2
		2016		(a)		2
Total Purchased Power		2018	$	(a)	$	12
		2017		(a)		25
		2016		(a)		30
Ameren Missouri and Ameren Illinois	Other Operations and	2018	$	3	$	6
rent and facility services	Maintenance	2017		(b)		(b)
		2016		(b)		(b)
Ameren Services support services	Other Operations and	2018		136		126
agreement	Maintenance	2017		149		139
		2016		129		123
Total Other Operations and		2018	$	139	$	132
Maintenance Expenses		2017		149		139
		2016		129		123
Money pool borrowings (advances)	(Interest Charges)	2018	$	1	$	(b)
	Other Income, Net	2017		1		(b)
		2016		(b)		(b)


(a)	Not applicable.


(b)	Amount less than $1 million.

NOTE 14 – 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 9 – Callaway Energy Center, and Note 13 – Related-party Transactions in this report.

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, 2018:



	2019		2020		2021		2022		2023		After 5 Years		Total
Ameren:
Minimum capital lease payments(a)(b)	$	32	$	32	$	33	$	32	$	264	$	—	$	393
Less amount representing interest	25		25		25		24		24		—		123
Present value of minimum capital lease payments	$	7	$	7	$	8	$	8	$	240	$	—	$	270
Operating leases	10		8		7		6		5		9		45
Total lease obligations	$	17	$	15	$	15	$	14	$	245	$	9	$	315
Ameren Missouri:
Minimum capital lease payments(b)(c)	$	32	$	32	$	33	$	32	$	264	$	—	$	393
Less amount representing interest	25		25		25		24		24		—		123
Present value of minimum capital lease payments	$	7	$	7	$	8	$	8	$	240	$	—	$	270
Operating leases	8		7		6		5		5		9		40
Total lease obligations	$	15	$	14	$	14	$	13	$	245	$	9	$	310
Ameren Illinois:
Operating leases	$	1	$	—	$	—	$	—	$	—	$	—	$	1


(a)	See Note 3 – Property, Plant, and Equipment, Net for additional information.


(b)	See Note 5 – Long-term Debt and Equity Financings for additional information on Ameren’s and Ameren Missouri’s capital lease agreements.

The following table presents total operating lease expenses included in “Operating Expenses” in the statement of income for the years ended December 31, 2018, 2017, and 2016:



	2018		2017		2016
Ameren	$	9	$	11	$	38
Ameren Missouri	8		10		34
Ameren Illinois	1		1		30

Other Obligations

To supply a portion of the fuel requirements of Ameren Missouri’s energy centers, Ameren Missouri has entered into various long-term commitments for the procurement of coal, natural gas, nuclear fuel, and methane gas. Ameren Missouri and Ameren Illinois also have entered into various long-term commitments for purchased power and natural gas for distribution. The table below presents our estimated minimum fuel, purchased power, and other commitments at December 31, 2018. Ameren’s and Ameren Illinois’ purchased power commitments include the Ameren Illinois 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, among other agreements, at December 31, 2018.



	Coal		Natural Gas(a)		Nuclear Fuel		Purchased Power(b)(c)		Methane Gas		Other		Total
Ameren:
2019	$	349	$	197	$	25	$	157	$	4	$	67	$	799
2020	160		143		43		54		4		41		445
2021	121		77		59		10		4		30		301
2022	72		27		14		—		3		26		142
2023	—		7		42		—		3		27		79
Thereafter	—		34		31		—		29		72		166
Total	$	702	$	485	$	214	$	221	$	47	$	263	$	1,932
Ameren Missouri:
2019	$	349	$	40	$	25	$	—	$	4	$	49	$	467
2020	160		31		43		—		4		26		264
2021	121		15		59		—		4		26		225
2022	72		5		14		—		3		26		120
2023	—		3		42		—		3		27		75
Thereafter	—		14		31		—		29		56		130
Total	$	702	$	108	$	214	$	—	$	47	$	210	$	1,281
Ameren Illinois:
2019	$	—	$	157	$	—	$	157	$	—	$	8	$	322
2020	—		112		—		54		—		5		171
2021	—		62		—		10		—		—		72
2022	—		22		—		—		—		—		22
2023	—		4		—		—		—		—		4
Thereafter	—		20		—		—		—		—		20
Total	$	—	$	377	$	—	$	221	$	—	$	13	$	611


(a)	Includes amounts for generation and for distribution.


(b)	The purchased power amounts for Ameren and Ameren Illinois exclude agreements for renewable energy credits through 2034 with various renewable energy suppliers due to the contingent nature of the payment amounts.


(c)	The purchased power amounts for Ameren and Ameren Missouri exclude a 102-megawatt power purchase agreement with a wind farm operator, which expires in 2024, due to the contingent nature of the payment amounts.

In January 2018, as required by the FEJA, Ameren Illinois entered into 10-year agreements to acquire zero emission credits. Annual zero emission credit commitment amounts will be published by the IPA each May prior to the start of the subsequent planning year. The amounts above reflect Ameren Illinois’ commitment to acquire approximately $26 million of zero emission credits through May 2019.

Environmental Matters

We are subject to various environmental laws, including statutes and regulations, enforced by federal, state, and local authorities. The development and operation of electric generation, transmission, and distribution facilities and natural gas storage, transmission, and distribution facilities can trigger compliance obligations with respect to environmental laws. These laws address emissions, discharges to water, water intake, 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 environmental regulations that have a significant impact on the electric utility industry. Over time, compliance with these regulations could be costly for Ameren Missouri, which operates coal-fired power plants. As of December 31, 2018, Ameren Missouri’s fossil fuel-fired energy centers represented 16% and 32% of Ameren’s and Ameren Missouri’s rate base, respectively. Regulations that apply to air emissions from the electric utility industry include the NSPS, the CSAPR, the MATS, and the National Ambient Air Quality Standards, which are subject to periodic review for certain pollutants. Collectively, these regulations cover a variety of pollutants, such as

SO2, particulate matter, NOx, mercury, toxic metals, and acid gases, and CO2 emissions from new power plants. Water intake and discharges from power plants are regulated under the Clean Water Act. Such regulation could require modifications to water intake structures or more stringent limitations on wastewater discharges at Ameren Missouri’s energy centers, either of which could result in significant capital expenditures. The management and disposal of coal ash is regulated under the CCR rule, which will require the closure of surface impoundments and the installations of dry ash handling systems at several of Ameren Missouri’s energy centers. The individual or combined effects of existing environmental regulations could result in significant capital expenditures, increased operating costs, or the closure or alteration of operations at some of Ameren Missouri’s energy centers. Ameren and Ameren Missouri expect that such compliance costs would be recoverable through rates, subject to MoPSC prudence review, but the timing of costs and their recovery could be subject to regulatory lag.

Ameren and Ameren Missouri estimate that they will need to make capital expenditures of $300 million to $400 million from 2019 through 2023 in order to comply with existing environmental regulations. Additional environmental controls beyond 2023 could be required. This estimate of capital expenditures includes expenditures required by the CCR regulations, by the Clean Water Act rule applicable to cooling water intake structures at existing power plants, and by effluent limitation guidelines applicable to steam electric generating units, all of which are discussed below. Ameren Missouri’s current plan for compliance with existing air emission regulations includes burning ultra-low-sulfur coal and installing new or optimizing existing pollution control equipment. The actual amount of capital expenditures required to comply with existing environmental regulations may vary substantially from the above estimate because of uncertainty as to whether the EPA will substantially revise regulatory obligations, exactly which compliance strategies will be used and their ultimate cost, among other things.

The following sections describe the more significant environmental laws and rules and environmental enforcement and remediation matters that affect or could affect our operations. The EPA has initiated an administrative review of several regulations and proposed amendments to regulations and guidelines, including to the effluent limitation guidelines and the CCR Rule, which could ultimately result in the revision of all or part of such rules.

Clean Air Act

Federal and state laws, including CSAPR, regulate emissions of SO2 and NOx through emission source reductions and the use and retirement of emission allowances. The first phase of the CSAPR emission reduction requirements became effective in 2015. The second phase of emission reduction requirements, which were revised by the EPA in 2016, became effective in 2017; additional emission reduction requirements may apply in subsequent years. To achieve compliance with the CSAPR, Ameren Missouri burns ultra-low-sulfur coal, operates two scrubbers at its Sioux energy center, and optimizes other existing pollution control equipment. Ameren Missouri expects to incur additional costs to lower 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 recovered from customers through the FAC or higher base rates.

CO2 Emissions Standards

In 2015, the EPA issued the Clean Power Plan, which would have established CO2 emissions standards applicable to existing power plants. The United States Supreme Court stayed the rule in February 2016, pending various legal challenges. In August 2018, the EPA proposed to repeal and replace the Clean Power Plan with a proposed new rule known as the Affordable Clean Energy Rule, which establishes emission guidelines for states to follow in developing plans to limit CO2 emissions from power plants. The EPA proposes to use certain efficiency measures as the best system of emission reduction for coal-fired power plants. The EPA is expected to finalize the Affordable Clean Energy rule in the first half of 2019. We cannot predict the outcome of EPA’s rulemaking or the outcome of legal challenges related to such rulemaking.

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 complaint, as amended in October 2013, alleged 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. The litigation has been divided into two phases: liability and remedy. In the first phase, in January 2017, the district court issued a liability ruling that the projects violated provisions of the Clean Air Act and Missouri law. In the second phase, the district court will determine the actions required to remedy the violations found in the liability phase. The EPA previously withdrew all claims for penalties and fines. Hearings on remedy-related issues are scheduled for April 2019. At the conclusion of both phases of the litigation, Ameren Missouri intends to appeal the liability ruling to the United States Court of Appeals for the Eighth Circuit.

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. Among other things and subject to economic and regulatory considerations, resolution of this matter could result in increased capital expenditures for the installation of pollution control equipment, as well as increased operations and maintenance expenses. We are unable to predict the ultimate resolution of this matter or the costs that might be incurred.

Clean Water Act

In July 2018, the United States Court of Appeals for the Second Circuit upheld the EPA’s Section 316(b) 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 a power plant’s cooling water 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 the cooling water intake structures rule. The rule will be implemented by Ameren Missouri during the permit renewal process of each energy center’s water discharge permit, which is expected to be completed by 2023.

In 2015, the EPA issued a rule to revise the effluent limitation guidelines applicable to steam electric generating units. These guidelines established national standards for water discharges that are based on the effectiveness of available control technology. The EPA’s 2015 rule prohibits effluent discharges of certain waste streams and imposes more stringent limitations on certain water discharges from power plants. In September 2017, the EPA published a rule that postponed the compliance dates by two years for the limitations applicable to two specific waste streams so that it could potentially revise those standards. Ameren Missouri is in the process of constructing wastewater treatment facilities that meet the limitations in these guidelines at three of its energy centers.

CCR Management

In 2015, the EPA issued the CCR rule, which established regulations regarding the management and disposal of CCR from coal-fired energy centers. These regulations affect CCR disposal and handling costs at Ameren Missouri’s energy centers. They require closure of impoundments if performance criteria relating to groundwater impacts and location restrictions are not achieved. In July 2018, the EPA issued revisions to the CCR rule that extended certain compliance deadlines and indicated that additional revisions to the CCR rule are likely. Ameren and Ameren Missouri have AROs of $135 million recorded on their respective balance sheets as of December 31, 2018, associated with CCR storage facilities that reflect the regulations issued in 2015. Ameren plans to close these CCR storage facilities between 2019 and 2023. The recent EPA revisions do not affect Ameren Missouri’s closure schedule. Ameren Missouri estimates it will need to make capital expenditures of $150 million to $200 million from 2019 through 2023 to implement its CCR management compliance plan, which includes installation of dry ash handling systems, waste water treatment facilities, and groundwater monitoring equipment.

Remediation

The Ameren Companies are involved in a number of remediation actions to clean up sites impacted by the use or disposal of materials containing hazardous substances. Federal and state laws can require responsible parties to fund remediation 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, 2018, Ameren Illinois had investigated and remediated the majority of the 44 former MGP sites in Illinois it owned or for which it was otherwise responsible. Ameren Illinois estimates it could substantially conclude remediation efforts at its remaining sites by 2023. The ICC allows Ameren Illinois to recover such remediation and related litigation costs from its electric and natural gas utility customers through environmental cost riders. Costs are subject to annual prudence review by the ICC. As of December 31, 2018, Ameren Illinois estimated the obligation related to these former MGP sites at $150 million to $212 million. Ameren and Ameren Illinois recorded a liability of $150 million to represent the estimated minimum obligation for these sites, as no other amount within the range was a better estimate.

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

Ameren Missouri participated in the investigation of various sites known as Sauget Area 2, located in Sauget, Illinois. In December 2018, Ameren Missouri signed a consent decree with the EPA to implement certain remedial measures at one of the disposal sites and reached an agreement with Solutia, Inc., the primary potentially responsible party for the Sauget Area 2, limiting Ameren Missouri’s cleanup obligations with respect to the other disposal sites. Remediation efforts at the site are expected to occur in 2020. As of December 31, 2018, Ameren Missouri recorded a liability of $1 million to represent its estimated minimum obligation for this site.

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.

NOTE 15 – SEGMENT INFORMATION

Ameren has four segments: Ameren Missouri, Ameren Illinois Electric Distribution, Ameren Illinois Natural Gas, and Ameren Transmission. The Ameren Missouri segment includes all of the operations of Ameren Missouri. Ameren Illinois Electric Distribution consists

of the electric distribution business of Ameren Illinois. Ameren Illinois Natural Gas consists of the natural gas business of Ameren Illinois. Ameren Transmission primarily consists of the aggregated electric transmission businesses of Ameren Illinois and ATXI. The category called Other primarily includes Ameren (parent) activities and Ameren Services.

Ameren Missouri has one segment. Ameren Illinois has three segments: Ameren Illinois Electric Distribution, Ameren Illinois Natural Gas, and Ameren Illinois Transmission. See Note 1 – Summary of Significant Accounting Policies for additional information regarding the operations of Ameren Missouri, Ameren Illinois, and ATXI.

Segment operating revenues and a majority of operating expenses are directly recognized and incurred by Ameren Illinois to each Ameren Illinois segment. Common operating expenses, miscellaneous income and expenses, interest charges, and income tax expense are allocated by Ameren Illinois to each Ameren Illinois segment based on certain factors, which primarily relate to the nature of the cost. Additionally, Ameren Illinois Transmission earns revenue from transmission service provided to Ameren Illinois Electric Distribution, other retail electric suppliers, and wholesale customers. The transmission expense for Illinois customers who have elected to purchase their power from Ameren Illinois is recovered through a cost recovery mechanism with no net effect on Ameren Illinois Electric Distribution earnings, as costs are offset by corresponding revenues. Transmission revenues from these transactions are reflected in Ameren Transmission’s and Ameren Illinois Transmission’s operating revenues. An intersegment elimination at Ameren and Ameren Illinois occurs to eliminate these transmission revenues and expenses.

The following tables present information about the reported revenue and specified items reflected in net income attributable to common shareholders and capital expenditures by segment at Ameren and Ameren Illinois for the years ended December 31, 2018, 2017, and 2016. Ameren, Ameren Missouri, and Ameren Illinois management review segment capital expenditure information rather than any individual or total asset amount.

Ameren



	Ameren Missouri		Ameren Illinois Electric Distribution		Ameren Illinois Natural Gas		Ameren Transmission			Other			Intersegment Eliminations			Ameren
2018
External revenues	$	3,555	$	1,544	$	814	$	378		$	—		$	—		$	6,291
Intersegment revenues	34		3		1		55		(a)	—			(93		)	—
Depreciation and amortization	550		259		65		77			4			—			955
Interest income	28		6		—		—			4			(5		)	33
Interest charges	200		73		38		75		(b)	19			(4		)	401
Income taxes	124		41		25		56			(9		)	—			237
Net income (loss) attributable to Ameren common shareholders	478		136		70		164			(33		)	—			815
Capital expenditures	914		503		311		562			5			(9		)	2,286
2017
External revenues	$	3,488	$	1,564	$	742	$	382		$	(2	)	$	—		$	6,174
Intersegment revenues	49		4		1		44		(a)	—			(98		)	—
Depreciation and amortization	533		239		59		60			5			—			896
Interest income	27		7		—		—			11			(11		)	34
Interest charges	207		73		36		67		(b)	19			(11		)	391
Income taxes	254		83		36		90			113			—			576
Net income (loss) attributable to Ameren common shareholders	323		131		60		140			(131		)	—			523
Capital expenditures	773		476		245		644			1			(7		)	2,132
2016
External revenues	$	3,470	$	1,544	$	753	$	309		$	—		$	—		$	6,076
Intersegment revenues	54		4		1		46		(a)	—			(105		)	—
Depreciation and amortization	514		226		55		43			7			—			845
Interest income	28		11		—		1			11			(11		)	40
Interest charges	211		72		34		58		(b)	18			(11		)	382
Income taxes	216		78		39		74			(25		)	—			382
Net income (loss) attributable to Ameren common shareholders	357		126		59		117			(6		)	—			653
Capital expenditures	738		470		181		689			4			(6		)	2,076


(a)	Ameren Transmission earns revenue from transmission service provided to Ameren Illinois Electric Distribution. See discussion of transactions above.


(b)	Ameren Transmission interest charges include an allocation of financing costs from Ameren (parent).

Ameren Illinois



	Ameren Illinois Electric Distribution		Ameren Illinois Natural Gas		Ameren Illinois Transmission			Intersegment Eliminations			Ameren Illinois
2018
External revenues	$	1,547	$	815	$	214		$	—		$	2,576
Intersegment revenues	—		—		53		(a)	(53		)	—
Depreciation and amortization	259		65		50			—			374
Interest income	6		—		—			—			6
Interest charges	73		38		38			—			149
Income taxes	41		25		32			—			98
Net income available to common shareholder	136		70		98			—			304
Capital expenditures	503		311		444			—			1,258
2017
External revenues	$	1,568	$	743	$	216		$	—		$	2,527
Intersegment revenues	—		—		42		(a)	(42		)	—
Depreciation and amortization	239		59		43			—			341
Interest income	7		—		—			—			7
Interest charges	73		36		35			—			144
Income taxes	83		36		47			—			166
Net income available to common shareholder	131		60		77			—			268
Capital expenditures	476		245		355			—			1,076
2016
External revenues	$	1,548	$	754	$	187		$	—		$	2,489
Intersegment revenues	—		—		45		(a)	(45		)	—
Depreciation and amortization	226		55		38			—			319
Interest income	11		—		1			—			12
Interest charges	72		34		34			—			140
Income taxes	78		39		41			—			158
Net income available to common shareholder	126		59		67			—			252
Capital expenditures	470		181		273			—			924


(a)	Ameren Illinois Transmission earns revenue from transmission service provided to Ameren Illinois Electric Distribution. See discussion of transactions above.

The following tables present disaggregated revenues by segment at Ameren and Ameren Illinois for the years ended December 31, 2018, 2017, and 2016. Economic factors affect the nature, timing, amount, and uncertainty of revenues and cash flows in a similar manner across customer classes. Revenues from alternative revenue programs have a similar distribution among customer classes as revenues from contracts with customers. Other revenues not associated with contracts with customers are presented in the Other customer classification, along with electric transmission and off-system revenues.

Ameren



	Ameren Missouri			Ameren Illinois Electric Distribution		Ameren Illinois Natural Gas		Ameren Transmission		Other			Intersegment Eliminations			Ameren
2018
Residential	$	1,560		$	867	$	—	$	—	$	—		$	—		$	2,427
Commercial	1,271			511		—		—		—			—			1,782
Industrial	312			130		—		—		—			—			442
Other	308		(a)	39		—		433		—			(92		)	688		(a)
Total electric revenues	$	3,451		$	1,547	$	—	$	433	$	—		$	(92	)	$	5,339
Residential	$	90		$	—	$	581	$	—	$	—		$	—		$	671
Commercial	37			—		159		—		—			—			196
Industrial	4			—		17		—		—			—			21
Other	7			—		58		—		—			(1		)	64
Total gas revenues	$	138		$	—	$	815	$	—	$	—		$	(1	)	$	952
Total revenues(b)	$	3,589		$	1,547	$	815	$	433	$	—		$	(93	)	$	6,291
2017
Residential	$	1,417		$	870	$	—	$	—	$	—		$	—		$	2,287
Commercial	1,208			527		—		—		—			—			1,735
Industrial	305			113		—		—		—			—			418
Other	481			58		—		426		(2		)	(96		)	867
Total electric revenues	$	3,411		$	1,568	$	—	$	426	$	(2	)	$	(96	)	$	5,307
Residential	$	77		$	—	$	531	$	—	$	—		$	—		$	608
Commercial	31			—		146		—		—			—			177
Industrial	4			—		12		—		—			—			16
Other	14			—		54		—		—			(2		)	66
Total gas revenues	$	126		$	—	$	743	$	—	$	—		$	(2	)	$	867
Total revenues(b)	$	3,537		$	1,568	$	743	$	426	$	(2	)	$	(98	)	$	6,174
2016
Residential	$	1,422		$	895	$	—	$	—	$	—		$	—		$	2,317
Commercial	1,224			517		—		—		—			—			1,741
Industrial	315			96		—		—		—			—			411
Other	435			40		—		355		1			(104		)	727
Total electric revenues	$	3,396		$	1,548	$	—	$	355	$	1		$	(104	)	$	5,196
Residential	$	77		$	—	$	530	$	—	$	—		$	—		$	607
Commercial	30			—		153		—		—			—			183
Industrial	4			—		10		—		—			—			14
Other	17			—		61		—		—			(2		)	76
Total gas revenues	$	128		$	—	$	754	$	—	$	—		$	(2	)	$	880
Total revenues(b)	$	3,524		$	1,548	$	754	$	355	$	1		$	(106	)	$	6,076


(a)	Includes $60 million for the year ended December 31, 2018, for the reduction to revenue for the excess amounts collected in rates related to the TCJA from January 1, 2018, through July 31, 2018. See Note 2 – Rate and Regulatory Matters for additional information.


(b)	The following table presents increases/(decreases) in revenues from alternative revenue programs and other revenues not from contracts with customers for the years ended December 31, 2018, 2017, and 2016:



	Ameren Missouri			Ameren Illinois Electric Distribution			Ameren Illinois Natural Gas			Ameren Transmission			Ameren
2018
Revenues from alternative revenue programs	$	(8	)	$	(3	)	$	(23	)	$	(25	)	$	(59	)
Other revenues not from contracts with customers	24			16			2			—			42
2017
Revenues from alternative revenue programs	$	(28	)	$	(5	)	$	5		$	13		$	(15	)
Other revenues not from contracts with customers	15			6			2			—			23
2016
Revenues from alternative revenue programs	$	8		$	(70	)	$	11		$	(1	)	$	(52	)
Other revenues not from contracts with customers	16			6			2			—			24

Ameren Illinois



	Ameren Illinois Electric Distribution		Ameren Illinois Natural Gas		Ameren Illinois Transmission		Intersegment Eliminations			Ameren Illinois
2018
Residential	$	867	$	581	$	—	$	—		$	1,448
Commercial	511		159		—		—			670
Industrial	130		17		—		—			147
Other	39		58		267		(53		)	311
Total revenues(a)	$	1,547	$	815	$	267	$	(53	)	$	2,576
2017
Residential	$	870	$	531	$	—	$	—		$	1,401
Commercial	527		146		—		—			673
Industrial	113		12		—		—			125
Other	58		54		258		(42		)	328
Total revenues(a)	$	1,568	$	743	$	258	$	(42	)	$	2,527
2016
Residential	$	895	$	530	$	—	$	—		$	1,425
Commercial	517		153		—		—			670
Industrial	96		10		—		—			106
Other	40		61		232		(45		)	288
Total revenues(a)	$	1,548	$	754	$	232	$	(45	)	$	2,489


(a)	The following table presents increases/(decreases) in revenues from alternative revenue programs and other revenues not from contracts with customers for the Ameren Illinois segments for the years ended December 31, 2018, 2017, and 2016:



	Ameren Illinois Electric Distribution			Ameren Illinois Natural Gas			Ameren Illinois Transmission			Ameren Illinois
2018
Revenues from alternative revenue programs	$	(3	)	$	(23	)	$	(25	)	$	(51	)
Other revenues not from contracts with customers	16			2			—			18
2017
Revenues from alternative revenue programs	$	(5	)	$	5		$	9		$	9
Other revenues not from contracts with customers	6			2			—			8
2016
Revenues from alternative revenue programs	$	(70	)	$	11		$	2		$	(57	)
Other revenues not from contracts with customers	6			2			—			8

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



Ameren	2018								2017
Quarter ended	March 31		June 30		September 30		December 31		March 31		June 30		September 30		December 31
Operating revenues(a)	$	1,585	$	1,563	$	1,724	$	1,419	$	1,515	$	1,537	$	1,723	$	1,399
Operating income(a)	273		385		533		166		242		387		569		212
Net income (loss)	153		240		359		69		104		194		290		(59		)	(b)
Net income (loss) attributable to Ameren common shareholders	$	151	$	239	$	357	$	68	$	102	$	193	$	288	$	(60	)
Earnings (loss) per common share – basic	$	0.62	$	0.98	$	1.46	$	0.28	$	0.42	$	0.79	$	1.19	$	(0.24	)
Earnings (loss) per common share – diluted(c)	$	0.62	$	0.97	$	1.45	$	0.28	$	0.42	$	0.79	$	1.18	$	(0.24	)

(a)

2017 amounts have been revised to reflect the adoption of accounting guidance on revenue from contracts with customers and the presentation of net periodic pension and postretirement benefit cost, effective for the Ameren Companies as of January 1, 2018. See Note 1 – Summary of Significant Accounting Policies and Note 10 – Retirement Benefits under Part II, Item 8, of this report for additional information.


(b)	Includes an increase to income tax expense of $154 million recorded in 2017 as a result of the TCJA.


(c)	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(a)		Operating Income(a)		Net Income (Loss)				Net Income (Loss) Available to Common Shareholder
March 31, 2018	$	792	$	90	$	39			$	38
March 31, 2017	791		47		6				5
June 30, 2018	955		258		169				168
June 30, 2017	934		230		121				120
September 30, 2018	1,129		394		295				294
September 30, 2017	1,116		412		235				234
December 31, 2018	713		7		(22		)		(22		)
December 31, 2017	696		33		(36		)	(b)	(36		)

(a)


(b)	Includes an increase to income tax expense of $32 million recorded in 2017 as a result of the TCJA.



Ameren Illinois Quarter ended	Operating Revenues(a)		Operating Income(a)		Net Income		Net Income Available to Common Shareholder
March 31, 2018	$	760	$	159	$	96	$	95
March 31, 2017	703		169		80		79
June 30, 2018	578		105		63		62
June 30, 2017	576		128		58		57
September 30, 2018	564		113		63		63
September 30, 2017	574		124		55		55
December 31, 2018	674		135		85		84
December 31, 2017	674		148		78		77

(a)

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