10-Q

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-Q

☒ Quarterly report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 for the Quarterly Period Ended June 30, 2024

OR

☐ Transition report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934
for the transition period from             to

Commission File Number	Exact name of registrant as specified in its charter; State of Incorporation; Address and Telephone Number	IRS Employer Identification No.
1-14756	Ameren Corporation	43-1723446

(Missouri Corporation)

1901 Chouteau Avenue

St. Louis, Missouri 63103

(314) 621-3222

1-2967 Union Electric Company 43-0559760

(Missouri Corporation)

1901 Chouteau Avenue

St. Louis, Missouri 63103

(314) 621-3222

1-3672 Ameren Illinois Company 37-0211380

(Illinois Corporation)

10 Richard Mark Way

Collinsville, Illinois 62234

(618) 343-8150

Securities Registered Pursuant to Section 12(b) of the Act:

Title of each class	Trading Symbol(s)	Name of each exchange on which registered
Common Stock, $0.01 par value per share	AEE	New York Stock Exchange

Indicate by check mark whether each registrant: (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.

Ameren Corporation	Yes	☒	No	☐
Union Electric Company	Yes	☒	No	☐
Ameren Illinois Company	Yes	☒	No	☐

Indicate by check mark whether each registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§ 232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files).

Ameren Corporation	Yes	☒	No	☐
Union Electric Company	Yes	☒	No	☐
Ameren Illinois Company	Yes	☒	No	☐

Indicate by check mark whether each registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

Ameren Corporation	Large accelerated filer	☒	Accelerated filer	☐	Non-accelerated filer	☐
			Smaller reporting company	☐	Emerging growth company	☐
Union Electric Company	Large accelerated filer	☐	Accelerated filer	☐	Non-accelerated filer	☒
			Smaller reporting company	☐	Emerging growth company	☐
Ameren Illinois Company	Large accelerated filer	☐	Accelerated filer	☐	Non-accelerated filer	☒
			Smaller reporting company	☐	Emerging growth company	☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.

Ameren Corporation	☐
Union Electric Company	☐
Ameren Illinois Company	☐

Indicate by check mark whether each registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).

Ameren Corporation	Yes	☐	No	☒
Union Electric Company	Yes	☐	No	☒
Ameren Illinois Company	Yes	☐	No	☒

The number of shares outstanding of each registrant’s classes of common stock as of July 31, 2024, was as follows:

Registrant	Title of each class of common stock	Shares outstanding
Ameren Corporation	Common stock, $0.01 par value per share	266,816,725
Union Electric Company	Common stock, $5 par value per share, held by Ameren Corporation	102,123,834
Ameren Illinois Company	Common stock, no par value, held by Ameren Corporation	25,452,373

This combined Form 10-Q is separately filed by Ameren Corporation, Union Electric Company, and Ameren Illinois Company. Each registrant hereto is filing on its own behalf all of the information contained in this quarterly report that relates to such registrant. Each registrant hereto is not filing any information that does not relate to such registrant, and therefore makes no representation as to any such information.

TABLE OF CONTENTS

		Page
Glossary of Terms and Abbreviations		1
Forward-looking Statements		1
PART I. Financial Information
Item 1.	Financial Statements (Unaudited)	4
	Ameren Corporation	4
	Consolidated Statement of Income and Comprehensive Income	4
	Consolidated Balance Sheet	5
	Consolidated Statement of Cash Flows	6
	Consolidated Statement of Shareholders’ Equity	7
	Union Electric Company (d/b/a Ameren Missouri)	8
	Consolidated Statement of Income	8
	Consolidated Balance Sheet	9
	Consolidated Statement of Cash Flows	10
	Consolidated Statement of Shareholders’ Equity	11
	Ameren Illinois Company (d/b/a Ameren Illinois)	12
	Statement of Income	12
	Balance Sheet	13
	Statement of Cash Flows	14
	Statement of Shareholders’ Equity	15
	Note 1. Summary of Significant Accounting Policies	16
	Note 2. Rate and Regulatory Matters	17
	Note 3. Short-term Debt and Liquidity	20
	Note 4. Long-term Debt and Equity Financings	21
	Note 5. Other Income, Net	23
	Note 6. Derivative Financial Instruments	23
	Note 7. Fair Value Measurements	25
	Note 8. Related-party Transactions	28
	Note 9. Commitments and Contingencies	29
	Note 10. Callaway Energy Center	33
	Note 11. Retirement Benefits	34
	Note 12. Income Taxes	35
	Note 13. Supplemental Information	35
	Note 14. Segment Information	38
Item 2.	Management’s Discussion and Analysis of Financial Condition and Results of Operations	42
Item 3.	Quantitative and Qualitative Disclosures About Market Risk	78
Item 4.	Controls and Procedures	78
PART II. Other Information
Item 1.	Legal Proceedings	78
Item 1A.	Risk Factors	78
Item 2.	Unregistered Sales of Equity Securities and Use of Proceeds	79
Item 5.	Other Information	79
Item 6.	Exhibits	81
Signatures		82

GLOSSARY OF TERMS AND ABBREVIATIONS

We use the words “our,” “we” or “us” with respect to certain information that relates to Ameren, Ameren Missouri, and Ameren Illinois, collectively. When appropriate, subsidiaries of Ameren Corporation are named specifically as their various business activities are discussed. Refer to the Form 10-K for a complete listing of glossary terms and abbreviations. Only new or significantly changed terms and abbreviations are included below.

Form 10-K – The combined Annual Report on Form 10-K for the year ended December 31, 2023, filed by the Ameren Companies with the SEC.

QTD – Three months ended June 30.

YTD – Six months ended June 30.

YoY – Compared with the year-ago period.

FORWARD-LOOKING STATEMENTS

Statements in this report not based on historical facts are considered “forward-looking” and, accordingly, involve risks and uncertainties that could cause actual results to differ materially from those discussed. Although such forward-looking statements have been made in good faith and are based on reasonable assumptions, there is no assurance that the expected results will be achieved. These statements include (without limitation) statements as to future expectations, beliefs, plans, projections, strategies, targets, estimates, objectives, events, conditions, and financial performance. In connection with the “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995, we are providing this cautionary statement to identify important factors that could cause actual results to differ materially from those anticipated. The following factors, in addition to those discussed within Risk Factors in the Form 10-K, and elsewhere in this report and in our other filings with the SEC, could cause actual results to differ materially from management expectations suggested in such forward-looking statements:

•regulatory, judicial, or legislative actions, and any changes in regulatory policies and ratemaking determinations, that may change regulatory recovery mechanisms, such as those that may result from any additional mitigation relief related to the operation of the Rush Island Energy Center that may be ordered by the United States District Court for the Eastern District of Missouri, the MoOPC’s request for rehearing of the MoPSC’s June 2024 financing order to authorize the issuance of securitized utility tariff bonds to finance the cost of the planned accelerated retirement of the Rush Island Energy Center, Ameren Missouri’s electric service regulatory rate review filed with the MoPSC in June 2024, Ameren Missouri’s proposed customer energy-efficiency plan under the MEEIA filed with the MoPSC in January 2024, Ameren Illinois’ December 2023 ICC order for the MYRP electric distribution service regulatory rate review that directed Ameren Illinois to file a revised Grid Plan and a request to update the associated MYRP revenue requirements for 2024 through 2027, both subsequently filed in March 2024, along with the appeal of the December 2023 order to the Illinois Appellate Court for the Fifth Judicial District, Ameren Illinois’ electric distribution service revenue requirement reconciliation adjustment request filed with the ICC in April 2024, Ameren Illinois’ appeal of the November 2023 ICC natural gas delivery service rate order to the Illinois Appellate Court for the Fifth Judicial District, and the August 2022 United States Court of Appeals for the District of Columbia Circuit ruling that vacated the FERC’s MISO ROE-determining orders and remanded the proceedings to the FERC;

•our ability to control costs and make substantial investments in our businesses, including our ability to recover costs and investments, and to earn our allowed ROEs, within frameworks established by our regulators, while maintaining affordability of services for our customers;

•the effect and duration of Ameren Illinois’ election to utilize MYRPs for electric distribution service ratemaking effective for rates beginning in 2024, including the effect of the reconciliation cap on the electric distribution revenue requirement;

•the effect of Ameren Illinois’ use of the performance-based formula ratemaking framework for its participation in electric energy-efficiency programs, and the related impact of the direct relationship between Ameren Illinois’ ROE and the 30-year United States Treasury bond yields;

•the effect on Ameren Missouri of any customer rate caps or limitations on increasing the electric service revenue requirement pursuant to Ameren Missouri’s election to use the PISA;

•Ameren Missouri’s ability to construct and/or acquire wind, solar, and other renewable energy generation facilities and battery storage, as well as natural gas-fired energy centers, extend the operating license for the Callaway Energy Center, retire fossil fuel-fired energy centers, and implement new or existing customer energy-efficiency programs, including any such construction, acquisition, retirement, or implementation in connection with its Smart Energy Plan, integrated resource plan, or emissions reduction goals, and to recover its cost of investment, a related return, and, in the case of customer energy-efficiency programs, any lost electric revenues in a timely manner, each of which is affected by the ability to obtain all necessary regulatory and project approvals, including CCNs from the MoPSC or any other required approvals for the addition of renewable resources and natural gas-fired energy centers;

•Ameren Missouri’s ability to use or transfer federal production and investment tax credits related to renewable energy projects; the cost of wind, solar, and other renewable generation and battery storage technologies; and our ability to obtain timely interconnection agreements with the MISO or other RTOs at an acceptable cost for each facility;

1

•the outcome of competitive bids related to requests for proposals and project approvals, including CCNs from the MoPSC and the ICC or any other required approvals, associated with the MISO’s long-range transmission planning;

•the inability of our counterparties to meet their obligations with respect to contracts, credit agreements, and financial instruments, including as they relate to the construction and acquisition of electric and natural gas utility infrastructure and the ability of counterparties to complete projects, which is dependent upon the availability of necessary materials and equipment, including those obligations that are affected by supply chain disruptions;

•advancements in energy technologies, including carbon capture, utilization, and sequestration, hydrogen fuel for electric production and energy storage, next generation nuclear, and large-scale long-cycle battery energy storage, and the impact of federal and state energy and economic policies with respect to those technologies;

•the effects of changes in federal, state, or local laws and other governmental actions, including monetary, fiscal, foreign trade, and energy policies;

•the effects of changes in federal, state, or local tax laws or rates, including the effects of the IRA and the 15% minimum tax on adjusted financial statement income, as well as additional regulations, interpretations, amendments, or technical corrections to or in connection with the IRA, and challenges to the tax positions taken by the Ameren Companies, if any, as well as resulting effects on customer rates and the recoverability of the minimum tax imposed under the IRA;

•the effects on energy prices and demand for our services resulting from customer growth patterns or usage, technological advances, including advances in customer energy efficiency, electric vehicles, electrification of various industries, energy storage, and private generation sources, which generate electricity at the site of consumption and are becoming more cost-competitive;

•the cost and availability of fuel, such as low-sulfur coal, natural gas, and enriched uranium used to produce electricity; the cost and availability of natural gas for distribution and the cost and availability of purchased power, including capacity, zero emission credits, renewable energy credits, and emission allowances; and the level and volatility of future market prices for such commodities and credits;

•disruptions in the delivery of fuel, failure of our fuel suppliers to provide adequate quantities or quality of fuel, or lack of adequate inventories of fuel, including nuclear fuel assemblies primarily from the one NRC-licensed supplier of assemblies for Ameren Missouri’s Callaway Energy Center;

•the cost and availability of transmission capacity for the energy generated by Ameren Missouri’s energy centers or required to satisfy our energy sales;

•the effectiveness of our risk management strategies and our use of financial and derivative instruments;

•the ability to obtain sufficient insurance, or, in the absence of insurance, the ability to timely recover uninsured losses from our customers;

•the impact of cyberattacks and data security risks on us, our suppliers, or other entities on the grid, which could, among other things, result in the loss of operational control of energy centers and electric and natural gas transmission and distribution systems and/or the loss of data, such as customer, employee, financial, and operating system information;

•acts of sabotage, which have increased in frequency and severity within the utility industry, war, terrorism, or other intentionally disruptive acts;

•business, economic, and capital market conditions, including the impact of such conditions on interest rates, inflation, and investments;

•the impact of inflation or a recession on our customers and the related impact on our results of operations, financial position, and liquidity;

•disruptions of the capital and credit markets, deterioration in credit metrics of the Ameren Companies, or other events that may have an adverse effect on the cost or availability of capital, including short-term credit and liquidity, and our ability to access the capital and credit markets on reasonable terms when needed;

•the actions of credit rating agencies and the effects of such actions;

•the impact of weather conditions and other natural conditions on us and our customers, including the impact of system outages and the level of wind and solar resources;

•the construction, installation, performance, and cost recovery of generation, transmission, and distribution assets;

•the ability to maintain system reliability during the transition to clean energy generation by Ameren Missouri and the electric utility industry, as well as Ameren Missouri’s ability to meet generation capacity obligations;

•the effects of failures of electric generation, electric and natural gas transmission or distribution, or natural gas storage facilities systems and equipment, which could result in unanticipated liabilities or unplanned outages;

•the operation of Ameren Missouri’s Callaway Energy Center, including planned and unplanned outages, as well as the ability to recover costs associated with such outages and the impact of such outages on off-system sales and purchased power, among other things;

•Ameren Missouri’s ability to recover the remaining investment and decommissioning costs associated with the retirement of an energy center, as well as the ability to earn a return on that remaining investment and those decommissioning costs;

•the impact of current environmental laws and new, more stringent, or changing requirements, including those related to NSR, CO2, NOx, and other emissions and discharges, Illinois emission standards, cooling water intake structures, CCR, energy efficiency, and wildlife protection, that could limit or terminate the operation of certain of Ameren Missouri’s energy centers, increase our operating costs or investment requirements, result in an impairment of our assets, cause us to sell our assets, reduce our customers’ demand for electricity or natural gas, or otherwise have a negative financial effect;

•the impact of complying with renewable energy standards in Missouri and Illinois and with the zero emission standard in Illinois;

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•the effectiveness of Ameren Missouri’s customer energy-efficiency programs and the related revenues and performance incentives earned under its MEEIA programs;

•Ameren Illinois’ ability to achieve the performance standards applicable to its electric distribution business and electric customer energy-efficiency goals and the resulting impact on its allowed ROE;

•labor disputes, work force reductions, our ability to retain professional and skilled-craft employees, changes in future wage and employee benefits costs, including those resulting from changes in discount rates, mortality tables, returns on benefit plan assets, and other assumptions;

•the impact of negative opinions of us or our utility services that our customers, investors, legislators, regulators, creditors, or other stakeholders may have or develop, which could result from a variety of factors, including failures in system reliability, failure to implement our investment plans or to protect sensitive customer information, increases in rates, negative media coverage, or concerns about ESG practices;

•the impact of adopting new accounting and reporting guidance;

•the effects of strategic initiatives, including mergers, acquisitions, and divestitures;

•legal and administrative proceedings;

•pandemics or other significant global health events, and their impacts on our results of operations, financial position, and liquidity; and

•the impacts of the Russian invasion of Ukraine and conflicts in the Middle East, related sanctions imposed by the United States and other governments, and any broadening of these or other global conflicts, including potential impacts on the cost and availability of fuel, natural gas, enriched uranium, and other commodities, materials, and services, the inability of our counterparties to perform their obligations, disruptions in the capital and credit markets, acts of sabotage or terrorism, including cyberattacks, and other impacts on business, economic, and geopolitical conditions, including inflation.

New factors emerge from time to time, and it is not possible for management to predict all of such factors, nor can it assess the impact of each such factor on the business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained or implied in any forward-looking statement. Given these uncertainties, undue reliance should not be placed on these forward-looking statements. Except to the extent required by the federal securities laws, we undertake no obligation to update or revise publicly any forward-looking statements to reflect new information or future events.

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PART I. FINANCIAL INFORMATION

ITEM 1. FINANCIAL STATEMENTS.

AMEREN CORPORATION

CONSOLIDATED STATEMENT OF INCOME AND COMPREHENSIVE INCOME

(Unaudited) (In millions, except per share amounts)

	Three Months Ended June 30,				Six Months Ended June 30,
	2024		2023		2024		2023
Operating Revenues:
Electric	$	1,521	$	1,585	$	2,885	$	3,175
Natural gas	172		175		624		647
Total operating revenues	1,693		1,760		3,509		3,822
Operating Expenses:
Fuel and purchased power	327		480		655		1,088
Natural gas purchased for resale	33		42		184		250
Other operations and maintenance	465		450		935		898
Depreciation and amortization	376		335		737		655
Taxes other than income taxes	131		124		266		251
Total operating expenses	1,332		1,431		2,777		3,142
Operating Income	361		329		732		680
Other Income, Net	103		82		192		160
Interest Charges	165		134		319		261
Income Before Income Taxes	299		277		605		579
Income Taxes	39		38		83		75
Net Income	260		239		522		504
Less: Net Income Attributable to Noncontrolling Interests	2		2		3		3
Net Income Attributable to Ameren Common Shareholders	$	258	$	237	$	519	$	501
Net Income	$	260	$	239	$	522	$	504
Other Comprehensive Loss, Net of Taxes
Pension and other postretirement benefit plan activity, net of income taxes (benefit) of $(1), $—, $(1), and $—, respectively	(2)		(1)		(3)		(2)
Comprehensive Income	258		238		519		502
Less: Comprehensive Income Attributable to Noncontrolling Interests	2		2		3		3
Comprehensive Income Attributable to Ameren Common Shareholders	$	256	$	236	$	516	$	499
Earnings per Common Share – Basic	$	0.97	$	0.90	$	1.95	$	1.91
Earnings per Common Share – Diluted	$	0.97	$	0.90	$	1.95	$	1.90
Weighted-average Common Shares Outstanding – Basic	266.7		262.6		266.5		262.4
Weighted-average Common Shares Outstanding – Diluted	266.8		263.2		266.8		263.2

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

4

AMEREN CORPORATION

CONSOLIDATED BALANCE SHEET

(Unaudited) (In millions, except per share amounts)

	June 30, 2024		December 31, 2023
ASSETS
Current Assets:
Cash and cash equivalents	$	19	$	25
Accounts receivable – trade (less allowance for doubtful accounts of $37 and $30, respectively)	514		494
Unbilled revenue	407		319
Miscellaneous accounts receivable	62		106
Inventories	740		733
Current regulatory assets	345		365
Other current assets	130		139
Total current assets	2,217		2,181
Property, Plant, and Equipment, Net	34,873		33,776
Investments and Other Assets:
Nuclear decommissioning trust fund	1,266		1,150
Goodwill	411		411
Regulatory assets	1,952		1,810
Pension and other postretirement benefits	566		581
Other assets	1,049		921
Total investments and other assets	5,244		4,873
TOTAL ASSETS	$	42,334	$	40,830
LIABILITIES AND EQUITY
Current Liabilities:
Current maturities of long-term debt	$	799	$	849
Short-term debt	691		536
Accounts and wages payable	774		1,136
Interest accrued	177		147
Customer deposits	197		176
Other current liabilities	655		501
Total current liabilities	3,293		3,345
Long-term Debt, Net	16,280		15,121
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes and tax credits, net	4,325		4,176
Regulatory liabilities	5,531		5,512
Asset retirement obligations	791		772
Other deferred credits and liabilities	446		426
Total deferred credits and other liabilities	11,093		10,886
Commitments and Contingencies (Notes 2, 9, and 10)
Shareholders’ Equity:
Common stock, $.01 par value, 400.0 shares authorized – shares outstanding of 266.8 and 266.3, respectively	3		3
Other paid-in capital, principally premium on common stock	7,246		7,216
Retained earnings	4,299		4,136
Accumulated other comprehensive loss	(9)		(6)
Total shareholders’ equity	11,539		11,349
Noncontrolling Interests	129		129
Total equity	11,668		11,478
TOTAL LIABILITIES AND EQUITY	$	42,334	$	40,830

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

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AMEREN CORPORATION
CONSOLIDATED STATEMENT OF CASH FLOWS
(Unaudited) (In millions)
	Six Months Ended June 30,
	2024		2023
Cash Flows From Operating Activities:
Net income	$	522	$	504
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	760		703
Amortization of nuclear fuel	38		36
Amortization of debt issuance costs and premium/discounts	9		8
Deferred income taxes and investment tax credits, net	76		66
Allowance for equity funds used during construction	(25)		(23)
Stock-based compensation costs	14		14
Other	13		(19)
Changes in assets and liabilities:
Receivables	(85)		173
Inventories	(7)		(44)
Accounts and wages payable	(210)		(335)
Taxes accrued	121		93
Regulatory assets and liabilities	(105)		(81)
Assets, other	(53)		(38)
Liabilities, other	100		34
Pension and other postretirement benefits	(112)		(114)
Counterparty collateral, net	(7)		134
Net cash provided by operating activities	1,049		1,111
Cash Flows From Investing Activities:
Capital expenditures	(1,892)		(1,822)
Nuclear fuel expenditures	(37)		(50)
Purchases of securities – nuclear decommissioning trust fund	(323)		(81)
Sales and maturities of securities – nuclear decommissioning trust fund	309		65
Other	11		(1)
Net cash used in investing activities	(1,932)		(1,889)
Cash Flows From Financing Activities:
Dividends on common stock	(356)		(330)
Dividends paid to noncontrolling interest holders	(3)		(3)
Short-term debt, net	156		260
Maturities of long-term debt	(350)		(100)
Issuances of long-term debt	1,470		997
Issuances of common stock	21		16
Employee payroll taxes related to stock-based compensation	(8)		(20)
Debt issuance costs	(18)		(9)
Other	—		(3)
Net cash provided by financing activities	912		808
Net change in cash, cash equivalents, and restricted cash	29		30
Cash, cash equivalents, and restricted cash at beginning of year	272		216
Cash, cash equivalents, and restricted cash at end of period	$	301	$	246

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

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AMEREN CORPORATION

CONSOLIDATED STATEMENT OF SHAREHOLDERS’ EQUITY

(Unaudited) (In millions, except per share amounts)

	Three Months Ended June 30,				Six Months Ended June 30,
	2024		2023		2024		2023
Common Stock	$	3	$	3	$	3	$	3
Other Paid-in Capital:
Beginning of period	7,228		6,861		7,216		6,860
Shares issued under the DRPlus and 401(k) plan	11		11		21		23
Stock-based compensation activity	7		8		9		(3)
Other paid-in capital, end of period	7,246		6,880		7,246		6,880
Retained Earnings:
Beginning of period	4,219		3,745		4,136		3,646
Net income attributable to Ameren common shareholders	258		237		519		501
Dividends on common stock	(178)		(165)		(356)		(330)
Retained earnings, end of period	4,299		3,817		4,299		3,817
Accumulated Other Comprehensive Loss:
Deferred retirement benefit costs, beginning of period	(7)		(2)		(6)		(1)
Change in deferred retirement benefit costs	(2)		(1)		(3)		(2)
Deferred retirement benefit costs, end of period	(9)		(3)		(9)		(3)
Total accumulated other comprehensive loss, end of period	(9)		(3)		(9)		(3)
Total Shareholders’ Equity	$	11,539	$	10,697	$	11,539	$	10,697
Noncontrolling Interests:
Beginning of period	129		129		129		129
Net income attributable to noncontrolling interest holders	2		2		3		3
Dividends paid to noncontrolling interest holders	(2)		(2)		(3)		(3)
Noncontrolling interests, end of period	129		129		129		129
Total Equity	$	11,668	$	10,826	$	11,668	$	10,826
Common stock shares outstanding at beginning of period	266.6		262.6		266.3		262.0
Shares issued under the DRPlus and 401(k) plan	0.2		0.1		0.3		0.2
Shares issued for stock-based compensation	—		—		0.2		0.5
Common stock shares outstanding at end of period	266.8		262.7		266.8		262.7
Dividends per common share	$	0.67	$	0.63	$	1.34	$	1.26

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

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UNION ELECTRIC COMPANY (d/b/a AMEREN MISSOURI)

CONSOLIDATED STATEMENT OF INCOME

(Unaudited) (In millions)

	Three Months Ended June 30,				Six Months Ended June 30,
	2024		2023		2024		2023
Operating Revenues:
Electric	$	864	$	918	$	1,578	$	1,759
Natural gas	24		23		85		105
Total operating revenues	888		941		1,663		1,864
Operating Expenses:
Fuel and purchased power	189		289		355		610
Natural gas purchased for resale	9		9		37		56
Other operations and maintenance	247		237		501		476
Depreciation and amortization	208		186		403		362
Taxes other than income taxes	91		88		178		168
Total operating expenses	744		809		1,474		1,672
Operating Income	144		132		189		192
Other Income, Net	49		22		93		41
Interest Charges	63		52		125		103
Income Before Income Taxes	130		102		157		130
Income Taxes (Benefit)	1		(1)		2		(2)
Net Income	129		103		155		132
Preferred Stock Dividends	1		1		2		2
Net Income Available to Common Shareholder	$	128	$	102	$	153	$	130

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

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UNION ELECTRIC COMPANY (d/b/a AMEREN MISSOURI)

CONSOLIDATED BALANCE SHEET

(Unaudited) (In millions, except per share amounts)

	June 30, 2024		December 31, 2023
ASSETS
Current Assets:
Cash and cash equivalents	$	—	$	—
Accounts receivable – trade (less allowance for doubtful accounts of $12 and $12, respectively)	211		204
Accounts receivable – affiliates	67		72
Unbilled revenue	271		163
Miscellaneous accounts receivable	30		26
Inventories	520		508
Current regulatory assets	124		101
Other current assets	63		68
Total current assets	1,286		1,142
Property, Plant, and Equipment, Net	17,938		17,250
Investments and Other Assets:
Nuclear decommissioning trust fund	1,266		1,150
Regulatory assets	733		755
Pension and other postretirement benefits	138		157
Other assets	194		152
Total investments and other assets	2,331		2,214
TOTAL ASSETS	$	21,555	$	20,606
LIABILITIES AND SHAREHOLDERS’ EQUITY
Current Liabilities:
Current maturities of long-term debt	$	—	$	350
Short-term debt	390		170
Borrowings from money pool	—		306
Accounts and wages payable	366		618
Accounts payable – affiliates	58		53
Taxes accrued	132		28
Interest accrued	82		69
Other current liabilities	234		153
Total current liabilities	1,262		1,747
Long-term Debt, Net	6,830		5,991
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes and tax credits, net	2,196		2,122
Regulatory liabilities	2,925		2,959
Asset retirement obligations	788		768
Other deferred credits and liabilities	88		56
Total deferred credits and other liabilities	5,997		5,905
Commitments and Contingencies (Notes 2, 8, 9, and 10)
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	3,075		2,725
Preferred stock	80		80
Retained earnings	3,800		3,647
Total shareholders’ equity	7,466		6,963
TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY	$	21,555	$	20,606

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

9

UNION ELECTRIC COMPANY (d/b/a AMEREN MISSOURI)

CONSOLIDATED STATEMENT OF CASH FLOWS

(Unaudited) (In millions)

	Six Months Ended June 30,
	2024		2023
Cash Flows From Operating Activities:
Net income	$	155	$	132
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	426		410
Amortization of nuclear fuel	38		36
Amortization of debt issuance costs and premium/discounts	3		3
Deferred income taxes and investment tax credits, net	38		10
Allowance for equity funds used during construction	(23)		(12)
Other	22		(20)
Changes in assets and liabilities:
Receivables	(121)		(9)
Inventories	(12)		(81)
Accounts and wages payable	(196)		(231)
Taxes accrued	118		103
Regulatory assets and liabilities	(31)		28
Assets, other	(30)		13
Liabilities, other	63		21
Pension and other postretirement benefits	(40)		(41)
Counterparty collateral, net	(3)		81
Net cash provided by operating activities	407		443
Cash Flows From Investing Activities:
Capital expenditures	(1,104)		(914)
Nuclear fuel expenditures	(37)		(50)
Purchases of securities – nuclear decommissioning trust fund	(323)		(81)
Sales and maturities of securities – nuclear decommissioning trust fund	309		65
Net cash used in investing activities	(1,155)		(980)
Cash Flows From Financing Activities:
Dividends on preferred stock	(2)		(2)
Short-term debt, net	220		44
Money pool borrowings, net	(306)		—
Maturities of long-term debt	(350)		—
Issuances of long-term debt	846		499
Capital contribution from parent	350		—
Debt issuance costs	(9)		(6)
Other	—		(3)
Net cash provided by financing activities	749		532
Net change in cash, cash equivalents, and restricted cash	1		(5)
Cash, cash equivalents, and restricted cash at beginning of year	10		13
Cash, cash equivalents, and restricted cash at end of period	$	11	$	8

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

10

UNION ELECTRIC COMPANY (d/b/a AMEREN MISSOURI)

CONSOLIDATED STATEMENT OF SHAREHOLDERS’ EQUITY

(Unaudited) (In millions)

	Three Months Ended June 30,				Six Months Ended June 30,
	2024		2023		2024		2023
Common Stock	$	511	$	511	$	511	$	511
Other Paid-in Capital:
Beginning of period	2,725		2,725		2,725		2,725
Capital contributions from parent	350		—		350		—
Other paid-in capital, end of period	3,075		2,725		3,075		2,725
Preferred Stock	80		80		80		80
Retained Earnings:
Beginning of period	3,672		3,139		3,647		3,111
Net income	129		103		155		132
Dividends on preferred stock	(1)		(1)		(2)		(2)
Retained earnings, end of period	3,800		3,241		3,800		3,241
Total Shareholders’ Equity	$	7,466	$	6,557	$	7,466	$	6,557

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

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

STATEMENT OF INCOME

(Unaudited) (In millions)

	Three Months Ended June 30,				Six Months Ended June 30,
	2024		2023		2024		2023
Operating Revenues:
Electric	$	618	$	627	$	1,227	$	1,337
Natural gas	148		152		539		543
Total operating revenues	766		779		1,766		1,880
Operating Expenses:
Purchased power	141		192		305		479
Natural gas purchased for resale	24		33		147		194
Other operations and maintenance	224		201		434		403
Depreciation and amortization	154		138		307		271
Taxes other than income taxes	35		32		79		74
Total operating expenses	578		596		1,272		1,421
Operating Income	188		183		494		459
Other Income, Net	37		41		68		78
Interest Charges	60		50		115		97
Income Before Income Taxes	165		174		447		440
Income Taxes	40		44		107		112
Net Income	125		130		340		328
Preferred Stock Dividends	1		1		1		1
Net Income Available to Common Shareholder	$	124	$	129	$	339	$	327

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

12

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

BALANCE SHEET

(Unaudited) (In millions)

	June 30, 2024		December 31, 2023
ASSETS
Current Assets:
Cash and cash equivalents	$	6	$	—
Advances to money pool	30		—
Accounts receivable – trade (less allowance for doubtful accounts of $25 and $18, respectively)	287		273
Accounts receivable – affiliates	11		35
Unbilled revenue	136		156
Miscellaneous accounts receivable	5		44
Inventories	216		225
Current regulatory assets	215		252
Other current assets	55		62
Total current assets	961		1,047
Property, Plant, and Equipment, Net	15,009		14,632
Investments and Other Assets:
Goodwill	411		411
Regulatory assets	1,189		1,035
Pension and other postretirement benefits	412		394
Other assets	656		603
Total investments and other assets	2,668		2,443
TOTAL ASSETS	$	18,638	$	18,122
LIABILITIES AND SHAREHOLDERS’ EQUITY
Current Liabilities:
Current maturities of long-term debt	$	300	$	—
Short-term debt	—		366
Borrowings from money pool	—		135
Accounts and wages payable	297		370
Accounts payable – affiliates	97		52
Customer deposits	161		141
Zero emission credit liabilities	64		35
Current regulatory liabilities	58		71
Other current liabilities	219		263
Total current liabilities	1,196		1,433
Long-term Debt, Net	5,551		5,232
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes and investment tax credits, net	1,967		1,906
Regulatory liabilities	2,466		2,418
Other deferred credits and liabilities	319		308
Total deferred credits and other liabilities	4,752		4,632
Commitments and Contingencies (Notes 2, 8, and 9)
Shareholders’ Equity:
Common stock, no par value, 45.0 shares authorized – 25.5 shares outstanding	—		—
Other paid-in capital	3,020		3,020
Preferred stock	49		49
Retained earnings	4,070		3,756
Total shareholders’ equity	7,139		6,825
TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY	$	18,638	$	18,122

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

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

STATEMENT OF CASH FLOWS

(Unaudited) (In millions)

	Six Months Ended June 30,
	2024		2023
Cash Flows From Operating Activities:
Net income	$	340	$	328
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	307		271
Amortization of debt issuance costs and premium/discounts	2		2
Deferred income taxes and investment tax credits, net	37		70
Allowance for equity funds used during construction	(2)		(10)
Other	8		12
Changes in assets and liabilities:
Receivables	27		182
Inventories	9		37
Accounts and wages payable	7		(92)
Taxes accrued	55		(36)
Regulatory assets and liabilities	(70)		(105)
Assets, other	(23)		(42)
Liabilities, other	32		13
Pension and other postretirement benefits	(43)		(46)
Counterparty collateral, net	5		53
Net cash provided by operating activities	691		637
Cash Flows From Investing Activities:
Capital expenditures	(717)		(844)
Money pool advances, net	(30)		—
Other	5		(2)
Net cash used in investing activities	(742)		(846)
Cash Flows From Financing Activities:
Dividends on common stock	(25)		—
Dividends on preferred stock	(1)		(1)
Short-term debt, net	(366)		(147)
Money pool borrowings, net	(135)		—
Maturities of long-term debt	—		(100)
Issuances of long-term debt	624		498
Debt issuance costs	(7)		(3)
Net cash provided by financing activities	90		247
Net change in cash, cash equivalents, and restricted cash	39		38
Cash, cash equivalents and restricted cash at beginning of year	234		191
Cash, cash equivalents, and restricted cash at end of period	$	273	$	229

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

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

STATEMENT OF SHAREHOLDERS’ EQUITY

(Unaudited) (In millions)

	Three Months Ended June 30,				Six Months Ended June 30,
	2024		2023		2024		2023
Common Stock	$	—	$	—	$	—	$	—
Other Paid-in Capital:	3,020		2,929		3,020		2,929
Preferred Stock	49		49		49		49
Retained Earnings:
Beginning of period	3,971		3,388		3,756		3,190
Net income	125		130		340		328
Dividends on common stock	(25)		—		(25)		—
Dividends on preferred stock	(1)		(1)		(1)		(1)
Retained earnings, end of period	4,070		3,517		4,070		3,517
Total Shareholders’ Equity	$	7,139	$	6,495	$	7,139	$	6,495

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

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AMEREN CORPORATION (Consolidated)

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

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

COMBINED NOTES TO FINANCIAL STATEMENTS

(Unaudited)

June 30, 2024

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 Illinois Company, doing business as Ameren Illinois, operates rate-regulated electric transmission, electric distribution, and natural gas distribution businesses in Illinois.

•ATXI operates a FERC rate-regulated electric transmission business in the MISO.

Ameren’s and Ameren Missouri’s financial statements are prepared on a consolidated basis and therefore include the accounts of their majority-owned subsidiaries. All intercompany transactions have been eliminated. Ameren Missouri’s subsidiaries were created for the ownership of renewable generation projects. Ameren Illinois has 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 statement 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 reporting periods. Actual results could differ from those estimates. The results of operations for an interim period may not give a true indication of results that may be expected for a full year. These financial statements should be read in conjunction with the financial statements and accompanying notes included in the Form 10-K.

Variable Interest Entities

As of June 30, 2024, and December 31, 2023, Ameren had unconsolidated variable interests in various equity method investments, primarily to advance clean and resilient energy technologies, totaling $75 million and $73 million, respectively, included in “Other assets” on Ameren’s consolidated balance sheet. Any earnings or losses related to these investments are included in “Other Income, Net” on Ameren’s consolidated statement of income and comprehensive income. Ameren is not the primary beneficiary of these investments because it does not have the power to direct matters that most significantly affect the activities of these variable interest entities. As of June 30, 2024, Ameren’s maximum exposure to loss related to these variable interests is limited to its investment of $75 million plus associated outstanding funding commitments of $12 million.

COLI

Ameren and Ameren Illinois have COLI, 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 June 30, 2024, the cash surrender value of COLI at Ameren and Ameren Illinois was $255 million (December 31, 2023 – $248 million) and $114 million (December 31, 2023 – $111 million), respectively, while total borrowings against the policies were $103 million (December 31, 2023 – $104 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. The net cash surrender value of Ameren’s COLI is affected by the investment performance of a separate account in which Ameren holds a beneficial interest.

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NOTE 2 – RATE AND REGULATORY MATTERS

Below is a summary of updates to significant regulatory proceedings and related legal proceedings. See Note 2 – Rate and Regulatory Matters under Part II, Item 8, of the Form 10-K for additional information and a summary of our regulatory frameworks. We are unable to predict the ultimate outcome of these matters, the timing of final decisions of the various agencies and courts, or the impact on our results of operations, financial position, or liquidity.

Missouri

2024 Electric Service Regulatory Rate Review

In June 2024, Ameren Missouri filed a request with the MoPSC seeking approval to increase its annual revenues for electric service by $446 million. The electric rate increase request is based on a 10.25% return on common equity, a capital structure composed of 52% common equity, a rate base of $14 billion, and a test year ended March 31, 2024, with certain pro-forma adjustments expected through an anticipated true-up date of December 31, 2024. Ameren Missouri also requested the continued use of the FAC and trackers for pension and postretirement benefits, uncertain income tax positions, certain excess deferred income taxes, and the utilization of production and investment tax credits or proceeds from the sale of tax credits allowed under the IRA, which the MoPSC previously authorized in earlier electric rate orders. The electric rate increase request reflects the following:

•increased infrastructure investments made under Ameren Missouri’s Smart Energy Plan, including increased cost of capital and depreciation expense. Included in these investments are 500 megawatts of solar generation investment for the Boomtown, Cass County and Huck Finn solar projects along with investments in the Callaway nuclear energy center and other dispatchable generation to support a reliable, low-cost and cleaner mix of energy resources;

•decreased costs resulting from the planned retirement of the Rush Island Energy Center; and

•decreased costs related to the extension of the retirement date of the Sioux Energy Center from 2030 to 2032, consistent with Ameren Missouri’s integrated resource plan filed with the MoPSC in September 2023, to ensure reliability.

The MoPSC proceeding relating to the proposed electric service rate changes will take place over a period of up to 11 months, with a decision by the MoPSC expected by May 2025 and new rates effective by June 2025. Ameren Missouri cannot predict the level of any electric service rate change the MoPSC may approve, whether the requested regulatory recovery mechanisms will be continued, or whether any rate change that may eventually be approved will be sufficient for Ameren Missouri to recover its costs and earn a reasonable return on its investments when the rate change goes into effect.

Generation Facilities

During 2022 and 2023, Ameren Missouri, and certain subsidiaries of Ameren Missouri, entered into agreements to acquire and/or construct various generation facilities. The solar generation facilities are eligible for recovery under the PISA. The following table provides information with respect to each agreement:

	Agreement type	Facility size	Status of MoPSC CCN	Status of FERC approval of acquisition	Anticipated in-service date(a)
Huck Finn Solar Project(b)(c)	Build-transfer	200-MW	Approved February 2023	Received March 2023	Fourth quarter 2024
Boomtown Solar Project(c)(d)	Build-transfer	150-MW	Approved April 2023	Received October 2023	Fourth quarter 2024(e)
Cass County Solar Project(d)	Development-transfer(f)	150-MW	Approved June 2024	Not applicable	Fourth quarter 2024
Vandalia Solar Project(c)(g)	Self-build	50-MW	Approved March 2024	Not applicable	Fourth quarter 2025
Bowling Green Solar Project(c)(g)	Self-build	50-MW	Approved March 2024	Not applicable	First quarter 2026
Split Rail Solar Project(g)	Build-transfer	300-MW	Approved March 2024	Requested July 2024	Mid-2026
Castle Bluff Natural Gas Project	Self-build	800-MW	Filed June 2024	Not applicable	Fourth quarter 2027

(a)Anticipated in-service dates are dependent on the timing of regulatory approvals and construction completion, among other things.

(b)The Huck Finn Solar Project is expected to support Ameren Missouri’s compliance with the state of Missouri’s renewable energy standard. Investments in the project will be eligible for recovery under the RESRAM. Ameren Missouri expects to close on the acquisition of the Huck Finn Solar Project in the fourth quarter of 2024.

(c)These projects collectively represent approximately $0.85 billion of expected capital expenditures.

(d)The Boomtown and Cass County solar projects are expected to support Ameren Missouri’s transition to renewable energy generation and serve customers under the Renewable Solutions Program.

(e)Ameren Missouri expects to close on the acquisition of the Boomtown Solar Project in August 2024.

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(f)In June 2024, Ameren Missouri acquired the Cass County Solar Project, which includes solar panels, project design, land rights, and engineering, procurement, and construction agreements, for approximately $250 million and took over construction management of the project.

(g)These solar projects are expected to support Ameren Missouri’s transition to renewable energy generation.

Securitization of Rush Island Energy Center Costs

In June 2024, the MoPSC issued a financing order authorizing the issuance of securitized utility tariff bonds by a wholly owned, special purpose subsidiary of Ameren Missouri to finance approximately $470 million of costs related to the planned accelerated retirement of the Rush Island Energy Center, which includes the expected remaining unrecovered net plant balance associated with the facility, among other costs. Ameren Missouri initially petitioned the MoPSC in November 2023 to finance $519 million of costs. The difference between the initial petition and final financing order will be considered for recovery in future rate proceedings involving the securitized utility tariff charge or base rates. Ameren Missouri will collect the amounts necessary to repay the bonds over approximately 15 years from the date of bond issuance. The financing order also includes a determination that the decision to retire the Rush Island Energy Center was reasonable and prudent. The MoPSC did not make a determination regarding the prudency of Ameren Missouri's prior actions that resulted in the adverse ruling in the NSR and Clean Air Act litigation discussed in Note 9 – Commitments and Contingencies. However, claims regarding such actions could be considered in future regulatory proceedings. If future regulatory proceedings result in revenue reductions based on Ameren Missouri’s prior actions that resulted in the adverse ruling in the NSR and Clean Air Act litigation, it could have a material adverse effect on the results of operations, financial position, and liquidity of Ameren and Ameren Missouri. In July 2024, the MoOPC filed a request for rehearing of the financing order. Ameren Missouri expects a decision on the rehearing request in August 2024. The decision on the rehearing request is subject to appeal. The timing of the issuance of securitized utility tariff bonds is dependent on the conclusion of any appeal process.

MEEIA

In January 2024, Ameren Missouri filed a proposed customer energy-efficiency plan with the MoPSC under the MEEIA. This filing proposed a three-year plan, which includes a portfolio of customer energy-efficiency programs, along with the continued use of the MEEIA rider, which allows Ameren Missouri to collect from customers its actual MEEIA program costs and related lost electric revenues. If the plan is approved, Ameren Missouri intends to invest $123 million annually in the proposed customer energy-efficiency programs from 2025 to 2027. In addition, Ameren Missouri requested performance incentives applicable to each plan year to earn revenues by achieving certain customer energy-efficiency savings and target spending goals. If 100% of the goals are achieved, Ameren Missouri would earn performance incentive revenues totaling $56 million over the three-year plan. Ameren Missouri also requested additional performance incentives applicable to each plan year totaling up to $14 million over the three-year plan, if Ameren Missouri exceeds 100% of the goals. In March 2024, the MoPSC staff and the MoOPC filed responses in opposition to the proposed customer energy-efficiency plan under the MEEIA. Ameren Missouri expects a decision by the MoPSC by October 2024, but cannot predict the ultimate outcome of this regulatory proceeding.

MISO Long-Range Transmission Projects CCN

In July 2022, the MISO approved the first tranche of projects related to a preliminary long-range transmission planning roadmap of projects through 2039. A portion of these projects were assigned or awarded via a competitive bid process to various utilities, including Ameren. In July 2024, ATXI filed a request for a CCN, among other things, with the MoPSC related to a portion of the MISO long-range transmission projects that it will construct within the MoPSC’s jurisdiction. A decision by the MoPSC is expected by mid-2025.

Illinois

MYRP

In December 2023, the ICC issued an order in Ameren Illinois' MYRP proceeding approving base rates for electric distribution services for 2024 through 2027 and rejecting Ameren Illinois' Grid Plan, which was addressed as part of the MYRP proceeding. Rate changes consistent with the December 2023 order became effective in January 2024 and remained effective through late June 2024, when new rates became effective pursuant to the June 2024 ICC rehearing order discussed below. The December 2023 order adopted an alternative methodology to establish a rate base and revenue requirements for the years 2024 through 2027 using Ameren Illinois’ previously approved 2022 year-end rate base. In January 2024, the ICC partially denied a rehearing requested by Ameren Illinois to revise the allowed ROE in the December 2023 order and granted Ameren Illinois’ rehearing request to reconsider the rate base for each year of the MYRP and to include a base level of investments to maintain grid reliability in each year of the MYRP. In June 2024, the ICC issued an order on Ameren Illinois’ rehearing request, which revised the rate bases for Ameren Illinois’ MYRP test years to include investments for 2023 through 2027, among other things. New rates became effective in late June 2024. For additional information on the ICC’s June 2024 rehearing order, see the table below. In July 2024, Ameren Illinois filed a request for rehearing of the ICC’s June 2024 rehearing order to include an asset associated with other postretirement benefits in the rate base. Subsequently, in August 2024, the ICC denied the rehearing request. The ICC rehearing denial

18

is subject to appeal. Also, in January 2024, Ameren Illinois filed an appeal of the December 2023 ICC order, including the 8.72% ROE, to the Illinois Appellate Court for the Fifth Judicial District. The court is under no deadline to address the appeal.

In July 2024, Ameren Illinois filed an update to its revised Grid Plan and revised MYRP to update the requested revenue requirements for 2024 through 2027. In July 2024, the ICC staff filed its recommendation regarding Ameren Illinois’ revised MYRP. An ICC decision on the revised Grid Plan and updated revenue requirements is expected by the end of 2024 with rates effective in January 2025.

The following table presents the approved revenue requirements and average annual rate base in the ICC’s June 2024 rehearing order, as well as the proposed revenue requirements and average annual rate base in Ameren Illinois’ July 2024 revised MYRP and the ICC staff’s July 2024 revised MYRP recommendation:

Year	Revenue Requirement (in millions)	Average Annual Rate Base (in billions)
ICC’s June 2024 Rehearing Order(a):
2024	$1,196	$4.0
2025	$1,282	$4.3
2026	$1,350	$4.5
2027	$1,397	$4.7
Ameren Illinois’ July 2024 Revised MYRP(a):
2024	$1,215	$4.3
2025	$1,300	$4.5
2026	$1,386	$4.8
2027	$1,446	$5.0
ICC Staff’s July 2024 Revised MYRP(a):
2024	$1,201	$4.2
2025	$1,281	$4.4
2026	$1,361	$4.6
2027	$1,414	$4.8

(a)Based on an allowed ROE of 8.72% and a capital structure composed of 50% common equity. The ROE is under appeal, as discussed above.

Using the 2023 revenue requirement as a starting point, the approved revenue requirements in the ICC’s June 2024 rehearing order represent a cumulative four-year increase of $285 million compared to a cumulative increase of $334 million in Ameren Illinois’ July 2024 revised MYRP and a cumulative increase of $302 million in the ICC staff’s July 2024 revised MYRP recommendation.

Ameren Illinois cannot predict the ultimate outcome of the appeal to the Illinois Appellate Court for the Fifth Judicial District, its revised Grid Plan filing, or its request to update the associated MYRP revenue requirements for 2024 through 2027.

2023 Electric Distribution Revenue Requirement Reconciliation Adjustment Request

In April 2024, Ameren Illinois filed for a reconciliation adjustment to its 2023 electric distribution service revenue requirement with the ICC. In July 2024, Ameren Illinois filed a revised reconciliation adjustment, requesting recovery of $158 million. The reconciliation adjustment reflects a capital structure composed of 50% common equity and Ameren Illinois’ actual 2023 recoverable costs and year-end rate base. In June 2024, the ICC staff submitted its calculation of the reconciliation adjustment, recommending recovery of $157 million. An ICC decision in this proceeding is required by December 2024, and any approved adjustment would be collected from customers in 2025. This is the final revenue requirement reconciliation under the IEIMA formula framework.

Electric Customer Energy-Efficiency Investments

In May 2024, Ameren Illinois filed its annual electric energy-efficiency formula rate update to increase its rates by $26 million with the ICC. An ICC decision in this proceeding is required by December 2024, with new rates effective January 2025.

2023 Natural Gas Delivery Service Rate Order

In November 2023, the ICC issued an order in Ameren Illinois’ January 2023 natural gas delivery service regulatory rate review, which resulted in an increase to its annual revenues for natural gas delivery service of $112 million based on a 9.44% allowed ROE, a capital structure composed of 50% common equity, and a rate base of approximately $2.85 billion. The order reflected a reduction of approximately $93 million of planned distribution and transmission capital investments included in Ameren Illinois’ requested revenue increase, which used a 2024 future test year. The new rates became effective on November 28, 2023.

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In December 2023, Ameren Illinois filed a request for rehearing of the ICC’s November 2023 order. The filing requested the ICC revise the order to include an allowed ROE of at least 9.89%, a capital structure composed of 52% common equity, and the reversal of the approximately $93 million reduction of planned distribution and transmission capital investments included in the order, among other things. In January 2024, the ICC denied Ameren Illinois’ rehearing request. Subsequently, in January 2024, Ameren Illinois filed an appeal of the November 2023 ICC order to the Illinois Appellate Court for the Fifth Judicial District. The court is under no deadline to address the appeal. Ameren Illinois cannot predict the ultimate outcome of this appeal.

QIP Reconciliation Hearing

In March 2021, Ameren Illinois filed a request with the ICC to initiate a reconciliation proceeding to determine the accuracy and prudence of natural gas capital investments recovered under the QIP rider during 2020. In October 2023, the Illinois Attorney General’s office challenged the recovery of capital investments that were made during 2020, alleging that the ICC should disallow approximately $53 million in natural gas capital investments as improper and imprudent, providing a potential over-recovery of approximately $3 million in 2020. In October 2023, the ICC staff filed testimony that supports the prudence and reasonableness of the capital investments made during 2020. Ameren Illinois’ 2020 QIP rate recovery request under review by the ICC was within the rate increase limitations allowed by law. The ICC is under no deadline to issue an order in this proceeding. Ameren Illinois cannot predict the ultimate outcome of this regulatory proceeding.

MISO Long-Range Transmission Projects CCN

In July 2022, the MISO approved the first tranche of projects related to a preliminary long-range transmission planning roadmap of projects through 2039. A portion of these projects were assigned or awarded via a competitive bidding process to various utilities, including Ameren. In February 2024, Ameren Illinois and ATXI filed a request for a CCN, among other things, with the ICC related to the portion of the MISO long-range transmission projects they will construct within the ICC’s jurisdiction. A decision by the ICC is expected by mid-2025.

Federal

FERC Complaint Cases

Since November 2013, the allowed base ROE for FERC-regulated transmission rate base under the MISO tariff has been subject to customer complaint cases and has been changed by various FERC orders. In May 2020, the FERC issued an order, which set the allowed base ROE to 10.02% and required refunds, with interest, for the periods November 2013 to February 2015 and from late September 2016 forward. Ameren and Ameren Illinois paid these refunds, including interest, by March 31, 2022. In June and July 2020, Ameren Missouri, Ameren Illinois, and ATXI, as well as various customers, petitioned the United States Court of Appeals for the District of Columbia Circuit for review of the May 2020 order, challenging certain aspects of the new ROE methodology established. The petition filed by Ameren Missouri, Ameren Illinois, and ATXI challenged the refunds required for the period from September 2016 to May 2020. In August 2022, the court issued a ruling that granted the customers’ petition for review, vacated the FERC’s previous MISO ROE-determining orders, and remanded the proceedings to the FERC. The court elected not to rule on the issues raised by Ameren Missouri, Ameren Illinois, and ATXI. The currently allowed base ROE of 10.02% will remain effective for customer billings, but the transmission rates charged during previous periods and the currently effective rates may be subject to refund if the base ROE is changed by the FERC in a future order. The FERC is under no deadline to issue an order related to these proceedings. A 50-basis-point change in the FERC-allowed ROE would affect Ameren’s and Ameren Illinois’ annual revenue by an estimated $21 million and $15 million, respectively, based on each company’s 2024 projected rate base. Ameren and Ameren Illinois are unable to predict the ultimate resolution of this matter; however, such resolution could have a material effect on their results of operations, financial position, and liquidity.

NOTE 3 – 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, and, in the case of Ameren Missouri and Ameren Illinois, short-term affiliate borrowings. See Note 4 – Short-term Debt and Liquidity under Part II, Item 8, of the Form 10-K for a description of our indebtedness provisions and other covenants as well as a description of money pool agreements.

Short-term Borrowings

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, and the issuance of letters of credit. As of June 30, 2024, 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 $1.9 billion. The Ameren Companies were in compliance with the covenants in their Credit Agreements as of June 30, 2024. As of June 30, 2024, the ratios of consolidated indebtedness to consolidated total capitalization, calculated in accordance with the provisions of the Credit Agreements, were 61%, 49%, and 45% for Ameren, Ameren Missouri, and Ameren Illinois, respectively.

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The following table presents commercial paper outstanding, net of issuance discounts, as of June 30, 2024, and December 31, 2023. There were no borrowings outstanding under the Credit Agreements as of June 30, 2024, or December 31, 2023.

	June 30, 2024		December 31, 2023
Ameren (parent)	$	301	$	—
Ameren Missouri	390		170
Ameren Illinois	—		366
Ameren consolidated	$	691	$	536

The following table summarizes the activity and relevant interest rates for Ameren (parent)’s, Ameren Missouri’s, and Ameren Illinois’ commercial paper issuances and borrowings under the Credit Agreements in the aggregate for the six months ended June 30, 2024 and 2023:

	Ameren (parent)			Ameren Missouri			Ameren Illinois			Ameren Consolidated
2024
Average daily amount outstanding	$	84		$	109		$	385		$	578
Weighted-average interest rate	5.55		%	5.53		%	5.57		%	5.56		%
Peak amount outstanding during period(a)	$	301		$	509		$	694		$	1,084
Peak interest rate	5.60		%	5.68		%	5.68		%	5.68		%
2023
Average daily amount outstanding	$	595		$	343		$	230		$	1,168
Weighted-average interest rate	5.14		%	5.04		%	5.10		%	5.10		%
Peak amount outstanding during period(a)	$	841		$	592		$	450		$	1,381
Peak interest rate	5.55		%	5.55		%	5.60		%	5.60		%

(a)The timing of peak outstanding commercial paper issuances and borrowings under the Credit Agreements varies by company. Therefore, the sum of individual company peak amounts may not equal the Ameren consolidated peak amount for the period.

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. The average interest rate for borrowings under the utility money pool for the three and six months ended June 30, 2024, was 5.51% and 5.41%, respectively (2023 – 5.28% and 5.04%, respectively). See Note 8 – Related-party Transactions for the amount of interest income and expense from the utility money pool agreements recorded by Ameren Missouri and Ameren Illinois for the three and six months ended June 30, 2024 and 2023.

NOTE 4 – LONG-TERM DEBT AND EQUITY FINANCINGS

Ameren

For the three and six months ended June 30, 2024, Ameren issued a total of 0.2 million and 0.3 million shares of common stock, under its DRPlus and 401(k) plan, and received proceeds of $4 million and $14 million, respectively. As of June 30, 2024, Ameren had a receivable of $7 million related to issuances of common stock under its DRPlus. In addition, in the first quarter of 2024, Ameren issued 0.2 million shares of common stock valued at $16 million upon the settlement of stock-based compensation awards.

There were no shares issued under the ATM program for the three and six months ended June 30, 2024. As of June 30, 2024, Ameren had approximately $770 million of common stock available for sale under the ATM program, which takes into account the forward sale agreements in effect as of June 30, 2024, discussed below.

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The forward sale agreements outstanding as of June 30, 2024, can be settled at Ameren’s discretion on or prior to dates ranging from October 3, 2024 to February 28, 2025. On a settlement date or dates, if Ameren elects to physically settle a forward sale agreement, Ameren will issue shares of common stock to the counterparties at the then-applicable forward sale price. The initial forward sale price for the agreements ranged from $76.69 to $89.31, with an average initial forward sale price of $80.45. Each initial forward sale price is subject to adjustment based on a floating interest rate factor equal to the overnight bank funding rate less a spread of 75 basis points, and will be subject to decrease on certain dates specified in the forward sale agreements by specified amounts related to expected dividends on shares of the common stock during the term of the forward sale agreements. If the overnight bank funding rate is less than the spread on any day, the interest rate factor will result in a reduction of the forward sale price. The forward sale agreements will be physically settled unless Ameren elects to settle in cash or to net share settle. At June 30, 2024, Ameren could have settled the forward sale agreements with physical delivery of 2.9 million shares of common stock to the respective counterparties in exchange for cash of $232 million. Alternatively, the forward sale agreements could have also been settled at June 30, 2024, with the counterparties delivering approximately $29 million of cash or approximately 0.4 million shares of common stock to Ameren. In connection with the forward sale agreements outstanding at June 30, 2024, the various counterparties, or their affiliates, borrowed from third parties and sold 2.9 million shares of common stock. The gross sales price of these shares totaled $232 million. Ameren has not received any proceeds from such sales of borrowed shares. The forward sale agreements have been classified as equity transactions.

Ameren Missouri

In January 2024, Ameren Missouri issued $350 million of 5.25% first mortgage bonds due January 2054, with interest payable semiannually on January 15 and July 15 of each year, beginning July 15, 2024. Net proceeds from this issuance were used for capital expenditures and to repay short-term debt.

In April 2024, Ameren Missouri issued $500 million of 5.20% first mortgage bonds due April 2034, with interest payable semiannually on April 1 and October 1 of each year, beginning October 1, 2024. Net proceeds from this issuance were used for capital expenditures and to repay short-term debt.

In April 2024, $350 million principal amount of Ameren Missouri’s 3.50% senior secured notes matured and were repaid with cash on hand.

Ameren Missouri received capital contributions totaling $350 million from Ameren (parent) during the three and six months ended June 30, 2024.

Ameren Illinois

In June 2024, Ameren Illinois issued $625 million of 5.55% first mortgage bonds due July 2054, with interest payable semiannually on January 1 and July 1 of each year, beginning January 1, 2025. Net proceeds from this issuance were used to repay short-term debt.

Indenture Provisions and Other Covenants

See Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of the Form 10-K for a description of our indenture provisions and other covenants, as well as restrictions on the payment of dividends. At June 30, 2024, 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 agreements.

Off-balance-sheet Arrangements

At June 30, 2024, none of the Ameren Companies had any material off-balance-sheet financing arrangements, other than their investment in variable interest entities and the multiple forward sale agreements under the ATM program relating to common stock. See Note 1 – Summary of Significant Accounting Policies for further detail concerning variable interest entities.

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NOTE 5 – OTHER INCOME, NET

The following table presents the components of “Other Income, Net” in the Ameren Companies’ statements of income for the three and six months ended June 30, 2024 and 2023:

	Three Months				Six Months
	2024		2023		2024		2023
Ameren:
Allowance for equity funds used during construction	$	16	$	14	$	25	$	23
Other interest income	13		9		21		17
Non-service cost components of net periodic benefit income(a)	76		63		152		127
Miscellaneous income	4		2		6		4
Earnings related to equity method investments	1		—		1		2
Donations	(2)		(2)		(4)		(4)
Miscellaneous expense	(5)		(4)		(9)		(9)
Total Other Income, Net	$	103	$	82	$	192	$	160
Ameren Missouri:
Allowance for equity funds used during construction	$	14	$	8	$	23	$	12
Other interest income	3		2		5		6
Non-service cost components of net periodic benefit income(a)	35		14		69		28
Miscellaneous income	—		1		2		2
Donations	(1)		(1)		(2)		(2)
Miscellaneous expense	(2)		(2)		(4)		(5)
Total Other Income, Net	$	49	$	22	$	93	$	41
Ameren Illinois:
Allowance for equity funds used during construction	$	2	$	6	$	2	$	10
Other interest income	9		6		15		10
Non-service cost components of net periodic benefit income	26		31		53		62
Miscellaneous income	2		1		3		2
Donations	(1)		(1)		(2)		(2)
Miscellaneous expense	(1)		(2)		(3)		(4)
Total Other Income, Net	$	37	$	41	$	68	$	78

(a)For the three and six months ended June 30, 2024, the non-service cost components of net periodic benefit income were adjusted by amounts deferred of $(11) million and $(20) million, respectively, 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. The deferral was $17 million and $34 million, respectively, for the three and six months ended June 30, 2023. See Note 11 – Retirement Benefits for additional information.

NOTE 6 – DERIVATIVE FINANCIAL INSTRUMENTS

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

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

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

•actual cash outlays for the purchase of these commodities that differ from anticipated cash outlays; and

•actual off-system sales revenues that differ from anticipated revenues.

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.

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. 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. The following disclosures exclude NPNS contracts and other non-derivative commodity contracts that are accounted for under the accrual method of accounting.

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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 June 30, 2024, and December 31, 2023, all contracts that met the definition of a derivative and were not eligible for the NPNS exception received regulatory deferral. The cash flows from our derivative financial instruments follow the cash flow classification of the hedged item.

The following table presents open gross commodity contract volumes by commodity type for derivative assets and liabilities as of June 30, 2024, and December 31, 2023. As of June 30, 2024, these contracts extended through October 2027, October 2029 and May 2032 for fuel oils, natural gas and power, respectively.

	Quantity (in millions)
	June 30, 2024			December 31, 2023
Commodity	Ameren Missouri	Ameren Illinois	Ameren	Ameren Missouri	Ameren Illinois	Ameren
Fuel oils (in gallons)	20	—	20	17	—	17
Natural gas (in mmbtu)	52	221	273	53	218	271
Power (in MWhs)	—	5	5	—	5	5
Uranium (pounds in thousands)	—	—	—	186	—	186

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 June 30, 2024, and December 31, 2023:

		June 30, 2024						December 31, 2023
	Balance Sheet Location	Ameren Missouri		Ameren Illinois		Ameren			Ameren Missouri		Ameren Illinois		Ameren
Fuel oils	Other current assets	$	2	$	—	$	2		$	2	$	—	$	2
Natural gas	Other current assets	1		3		4			—		—		—
	Other assets	2		1		3			3		3		6
Power	Other current assets	15		—		15			5		—		5
Uranium	Other current assets	—		—		—			9		—		9
	Total assets	$	20	$	4	$	24		$	19	$	3	$	22
Fuel oils	Other current liabilities	$	1	$	—	$	1		$	1	$	—	$	1
	Other deferred credits and liabilities	—		—		—			1		—		1
Natural gas	Other current liabilities	9		33		42			12		45		57
	Other deferred credits and liabilities	8		28		36			10		30		40
Power	Other current liabilities	1		11		12			1		12		13
	Other deferred credits and liabilities	—		50		50			—		56		56
	Total liabilities	$	19	$	122	$	141		$	25	$	143	$	168

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.

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The following table provides the recognized gross derivative balances and the net amounts of those derivatives subject to an enforceable master netting arrangement or similar agreement as of June 30, 2024, and December 31, 2023:

			Gross Amounts Not Offset in the Balance Sheet
Commodity Contracts Eligible to be Offset	Gross Amounts Recognized in the Balance Sheet		Derivative Instruments		Cash Collateral Received/Posted(a)		Net Amount
June 30, 2024
Assets:
Ameren Missouri	$	20	$	5	$	—	$	15
Ameren Illinois	4		2		—		2
Ameren	$	24	$	7	$	—	$	17
Liabilities:
Ameren Missouri	$	19	$	5	$	—	$	14
Ameren Illinois	122		2		—		120
Ameren	$	141	$	7	$	—	$	134
December 31, 2023
Assets:
Ameren Missouri	$	19	$	6	$	—	$	13
Ameren Illinois	3		1		—		2
Ameren	$	22	$	7	$	—	$	15
Liabilities:
Ameren Missouri	$	25	$	6	$	—	$	19
Ameren Illinois	143		1		6		136
Ameren	$	168	$	7	$	6	$	155

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

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. As of June 30, 2024, if counterparty groups were to fail completely to perform on contracts, the Ameren Companies’ maximum exposure related to derivative assets, predominantly from financial institutions, would have been immaterial with or without consideration of the application of master netting arrangements or similar agreements and collateral held.

Certain of our derivative instruments 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 additional collateral required is the net liability position allowed under master netting arrangements or similar agreements, assuming (1) the credit risk-related contingent features underlying these arrangements were triggered and (2) those counterparties with rights to do so requested collateral. The following table presents, as of June 30, 2024, 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:

	Aggregate Fair Value of Derivative Liabilities(a)		Cash Collateral Posted		Potential Aggregate Amount of Additional Collateral Required(b)
Ameren Missouri	$	19	$	—	$	13
Ameren Illinois	61		—		59
Ameren	$	80	$	—	$	72

(a)Before consideration of master netting arrangements or similar agreements.

(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 7 – 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. Fair value measurements are classified in three levels based on the fair value hierarchy as defined by GAAP. See Note 8 – Fair Value Measurements under Part II, Item 8, of the Form 10-K for information related to hierarchy levels and valuation techniques.

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We consider nonperformance risk in our valuation of derivative instruments by analyzing our own credit standing and the credit standing of our counterparties, and by considering any credit enhancements (e.g., collateral). 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 the three and six months ended June 30, 2024 or 2023. At June 30, 2024, and December 31, 2023, 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 June 30, 2024, and December 31, 2023:

		June 30, 2024									December 31, 2023
		Level 1		Level 2		Level 3		Total			Level 1		Level 2		Level 3		Total
Assets:
Ameren Missouri
	Derivative assets – commodity contracts:
	Fuel oils	$	1	$	—	$	1	$	2		$	2	$	—	$	—	$	2
	Natural gas	—		3		—		3			—		3		—		3
	Power	—		—		15		15			—		—		5		5
	Uranium	—		—		—		—			—		—		9		9
	Total derivative assets – commodity contracts	$	1	$	3	$	16	$	20		$	2	$	3	$	14	$	19
	Nuclear decommissioning trust fund:
	Equity securities:
	U.S. large capitalization	$	842	$	—	$	—	$	842		$	787	$	—	$	—	$	787
	Debt securities:
	U.S. Treasury and agency securities	—		178		—		178			—		150		—		150
	Corporate bonds	—		154		—		154			—		136		—		136
	Other	—		82		—		82			—		68		—		68
	Total nuclear decommissioning trust fund	$	842	$	414	$	—	$	1,256	(a)	$	787	$	354	$	—	$	1,141	(a)
	Total Ameren Missouri	$	843	$	417	$	16	$	1,276		$	789	$	357	$	14	$	1,160
Ameren Illinois
	Derivative assets – commodity contracts:
	Natural gas	—		1		3		4			—		1		2		3
	Total Ameren Illinois	$	—	$	1	$	3	$	4		$	—	$	1	$	2	$	3
Ameren
	Derivative assets – commodity contracts(b)	$	1	$	4	$	19	$	24		$	2	$	4	$	16	$	22
	Nuclear decommissioning trust fund(c)	842		414		—		1,256		(a)	787		354		—		1,141		(a)
	Total Ameren	$	843	$	418	$	19	$	1,280		$	789	$	358	$	16	$	1,163
Liabilities:
Ameren Missouri
	Derivative liabilities – commodity contracts:
	Fuel oils	$	1	$	—	$	—	$	1		$	2	$	—	$	—	$	2
	Natural gas	—		16		1		17			—		19		3		22
	Power	—		—		1		1			—		—		1		1
	Total Ameren Missouri	$	1	$	16	$	2	$	19		$	2	$	19	$	4	$	25
Ameren Illinois
	Derivative liabilities – commodity contracts:
	Natural gas	$	2	$	52	$	7	$	61		$	4	$	60	$	11	$	75
	Power	—		—		61		61			—		—		68		68
	Total Ameren Illinois	$	2	$	52	$	68	$	122		$	4	$	60	$	79	$	143
Ameren
	Derivative liabilities – commodity contracts(b)	$	3	$	68	$	70	$	141		$	6	$	79	$	83	$	168

(a)Balance excludes $10 million and $9 million of cash and cash equivalents, receivables, payables, and accrued income, net, for June 30, 2024, and December 31, 2023, respectively.

(b)See the Ameren Missouri and Ameren Illinois sections of the table for a breakout of the fair value of Ameren’s derivative assets and liabilities by type of commodity.

(c)See the Ameren Missouri section of the table for a breakout of the fair value of Ameren’s nuclear decommissioning trust fund by investment type.

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Level 3 fuel oils, natural gas, and uranium 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 three and six months ended June 30, 2024 and 2023:

	2024						2023
	Ameren Missouri		Ameren Illinois		Ameren		Ameren Missouri		Ameren Illinois		Ameren
For the three months ended June 30:
Beginning balance at April 1	$	2	$	(54)	$	(52)	$	5	$	(52)	$	(47)
Realized and unrealized gains/(losses) included in regulatory assets/liabilities	15		(12)		3		14		(20)		(6)
Settlements	(3)		5		2		(5)		4		(1)
Ending balance at June 30	$	14	$	(61)	$	(47)	$	14	$	(68)	$	(54)
Change in unrealized gains/(losses) related to assets/liabilities held at June 30	$	14	$	(12)	$	2	$	14	$	(20)	$	(6)
For the six months ended June 30:
Beginning balance at January 1	$	4	$	(68)	$	(64)	$	12	$	(33)	$	(21)
Realized and unrealized gains/(losses) included in regulatory assets/liabilities	14		(2)		12		8		(41)		(33)
Settlements	(4)		9		5		(6)		6		—
Ending balance at June 30	$	14	$	(61)	$	(47)	$	14	$	(68)	$	(54)
Change in unrealized gains/(losses) related to assets/liabilities held at June 30	$	14	$	—	$	14	$	14	$	(35)	$	(21)

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 either net income or other comprehensive 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 June 30, 2024, and December 31, 2023:

			Fair Value						Weighted Average(b)
	Commodity		Assets		Liabilities	Valuation Technique(s)	Unobservable Input(a)	Range
2024	Power(c)	$	15	$	(62)	Discounted cash flow	Average forward peak and off-peak pricing – forwards/swaps ($/MWh)	33 – 70	43
							Nodal basis ($/MWh)	(10) – (1)	(5)
2023	Power(c)	$	5	$	(69)	Discounted cash flow	Average forward peak and off-peak pricing – forwards/swaps ($/MWh)	31 – 65	43
							Nodal basis ($/MWh)	(8) – (1)	(5)

(a)Generally, significant increases (decreases) in these inputs in isolation would result in a significantly higher (lower) fair value measurement.

(b)Unobservable inputs were weighted by relative fair value.

(c)Valuations use visible forward prices adjusted for nodal-to-hub basis differentials.

The following table sets forth the carrying amount and, by level within the fair value hierarchy, the fair value of long-term debt (including current portion) disclosed, but not recorded, at fair value as of June 30, 2024, and December 31, 2023:

Long-Term Debt (Including Current Portion):	Carrying Amount(a)		Fair Value
			Level 2		Level 3			Total
	June 30, 2024
Ameren	$	17,079	$	14,990	$	460	(b)	$	15,450
Ameren Missouri	6,830		6,069		—			6,069
Ameren Illinois	5,851		5,251		—			5,251
	December 31, 2023
Ameren	$	15,970	$	14,366	$	467	(b)	$	14,833
Ameren Missouri	6,341		5,800		—			5,800
Ameren Illinois	5,232		4,867		—			4,867

(a)Included unamortized debt issuance costs, which were excluded from the fair value measurement, of $124 million, $53 million, and $52 million for Ameren, Ameren Missouri, and Ameren Illinois, respectively, as of June 30, 2024. Included unamortized debt issuance costs, which were excluded from the fair value measurement, of $111 million, $45 million, and $47 million for Ameren, Ameren Missouri, and Ameren Illinois, respectively, as of December 31, 2023.

(b)The Level 3 fair value amount consists of ATXI’s senior unsecured notes.

The Ameren Companies’ carrying amounts of cash, cash equivalents, and restricted cash approximate fair value and are considered Level 1 in the fair value hierarchy. The Ameren Companies’ short-term borrowings approximate fair value because of the short-term nature of these instruments and are considered Level 2 in the fair value hierarchy.

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NOTE 8 – RELATED-PARTY TRANSACTIONS

In the ordinary 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. For a discussion of material related-party agreements and money pool agreements, see Note 13 – Related-party Transactions and Note 4 – Short-term Debt and Liquidity under Part II, Item 8, of the Form 10-K.

Support Services Agreements

Ameren Missouri and Ameren Illinois had long-term receivables included in “Other assets” from Ameren Services of $22 million and $24 million, respectively, as of June 30, 2024, and $31 million and $34 million, respectively, as of December 31, 2023, related to Ameren Services’ allocated portion of Ameren’s pension and postretirement benefit plans.

In December 2023, ATXI placed in service a transmission operations control center. Rental revenues received by ATXI from Ameren Services associated with this facility are affiliate transactions and are eliminated in consolidation for Ameren’s consolidated financial statements. Ameren Services’ rental expenses incurred are subsequently allocated to Ameren Missouri and Ameren Illinois as part of the Ameren Services support agreement.

Tax Allocation Agreement

See Note 1 – Summary of Significant Accounting Policies under Part II, Item 8, of the Form 10-K 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 June 30, 2024, and December 31, 2023:

	June 30, 2024				December 31, 2023
	Ameren Missouri		Ameren Illinois		Ameren Missouri		Ameren Illinois
Income taxes payable to parent(a)	$	—	$	44	$	—	$	2
Income taxes receivable from parent(b)	54		—		56		22

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

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

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Effects of Related-party Transactions on the Statement of Income

The following table presents the impact on Ameren Missouri and Ameren Illinois of related-party transactions for the three and six months ended June 30, 2024 and 2023:

				Three Months				Six Months
Agreement	Income Statement Line Item			Ameren Missouri		Ameren Illinois		Ameren Missouri		Ameren Illinois
Ameren Missouri power supply	Operating Revenues	2024	$	(b)	$	(a)	$	(b)	$	(a)
agreements with Ameren Illinois		2023		(b)		(a)		(b)		(a)
Ameren Missouri and Ameren Illinois	Operating Revenues	2024	$	8	$	(b)	$	15	$	(b)
rent and facility services		2023		8		(b)		18		(b)
Ameren Missouri and Ameren Illinois miscellaneous	Operating Revenues	2024	$	1	$	(b)	$	1	$	1
support services		2023		(b)		(b)		(b)		(b)
Total Operating Revenues		2024	$	9	$	(b)	$	16	$	1
		2023		8		(b)		18		(b)
Ameren Illinois power supply	Purchased Power	2024	$	(a)	$	(b)	$	(a)	$	(b)
agreements with Ameren Missouri		2023		(a)		(b)		(a)		(b)
Ameren Missouri and Ameren Illinois	Purchased Power	2024	$	2	$	1	$	4	$	1
transmission services from ATXI		2023		1		(b)		1		(b)
Total Purchased Power		2024	$	2	$	1	$	4	$	1
		2023		1		(b)		1		(b)
Ameren Missouri and Ameren Illinois	Other Operations and Maintenance	2024	$	(b)	$	(b)	$	(b)	$	(b)
rent and facility services		2023		(b)		(b)		(b)		2
Ameren Services support services	Other Operations and Maintenance	2024	$	43	$	40	$	81	$	77
agreement		2023		35		33		70		68
Total Other Operations and		2024	$	43	$	40	$	81	$	77
Maintenance		2023		35		33		70		70
Money pool interest	(Interest Charges)/Other Income, Net	2024	$	(b)	$	(b)	$	(3)	$	(2)
		2023		(b)		(b)		(b)		(b)

(a)Not applicable.

(b)Amount less than $1 million.

NOTE 9 – 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 the notes to our financial statements in this report and in the Form 10-K, will not have a material adverse effect on our results of operations, financial position, or liquidity.

Reference is made to Note 1 – Summary of Significant Accounting Policies, Note 2 – Rate and Regulatory Matters, Note 9 – Callaway Energy Center, Note 13 – Related-party Transactions, and Note 14 – Commitments and Contingencies under Part II, Item 8, of the Form 10-K. See also Note 1 – Summary of Significant Accounting Policies, Note 2 – Rate and Regulatory Matters, Note 8 – Related-party Transactions, and Note 10 – Callaway Energy Center of this report.

Environmental Matters

Our electric generation, transmission, and distribution and natural gas distribution and storage operations must comply with a variety of statutes and regulations relating to the protection of the environment and human health and safety, including permitting programs implemented by federal, state, and local authorities. Such environmental laws address air emissions; discharges to water bodies; the storage, handling and disposal of hazardous substances and waste materials; siting and land use requirements; and potential ecological impacts. Complex and lengthy processes are required to obtain and renew approvals, permits, and licenses for new, existing, or modified energy-related facilities. Additionally, the use and handling of various chemicals or hazardous materials require release prevention plans and emergency response procedures. We employ dedicated personnel knowledgeable in environmental matters to oversee our business activities’ compliance with requirements of environmental laws.

Environmental regulations have a significant impact on the electric utility industry and compliance with these regulations could be costly for Ameren Missouri, which operates coal-fired power plants. Regulations under the Clean Air Act that apply to 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

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pollutants. Collectively, these regulations cover a variety of pollutants, such as SO2, particulate matter, NOx, mercury, toxic metals and acid gases, and CO2 emissions. Regulations implementing the Clean Water Act govern both intake and discharges of water, as well as evaluation of the ecological and biological impact of those operations, and could require modifications to water intake structures or more stringent limitations on wastewater discharges. Depending upon the scope of modifications ultimately required by state regulators, capital expenditures associated with these modifications could be significant. The management and disposal of coal ash is regulated under the Resource Conservation and Recovery Act and the CCR Rule, which require the closure of surface impoundments at Ameren Missouri’s coal-fired energy centers. The individual or combined effects of compliance with existing and new 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.

Additionally, Ameren Missouri’s wind generation facilities may be subject to operating restrictions to limit the impact on protected species. Since 2021, Ameren Missouri’s High Prairie Renewable Energy Center curtailed nighttime operations from April through October to limit impacts on protected species during the critical biological season. Seasonal nighttime curtailment began again in April 2024, but the extent and duration of the curtailment is currently unknown as assessment of mitigation technologies is ongoing. Ameren Missouri does not anticipate these operating curtailments will have a material impact on its results of operations, financial position, or liquidity.

Ameren and Ameren Missouri estimate that they will need to make capital expenditures of $90 million to $120 million from 2024 through 2028 to comply with environmental regulations. These estimates exclude capital expenditures that may be necessary to comply with regulations issued by the EPA in 2024 relating to CO2 emissions, MATS, effluent limitations guidelines, and CCR management, which Ameren and Ameren Missouri are assessing and are discussed below. Additional capital expenditures for environmental controls beyond 2028 could be required. This estimate of capital expenditures includes surface impoundment closure and corrective action measures required by the 2015 CCR Rule and modifications to cooling water intake structures at existing power plants under Clean Water Act rules in place prior to 2024, all of which are discussed below. In addition to planned retirements of coal-fired energy centers identified in the 2023 IRP filed with the MoPSC in September 2023 and as noted below with respect to the NSR and Clean Air Act litigation and Illinois emissions standards discussed in Note 14 – Commitments and Contingencies under Part II, Item 8, of the Form 10-K, Ameren Missouri’s current plan for compliance with existing air emission regulations includes burning low-sulfur coal and installing new or optimizing existing air pollution control equipment. The actual amount of capital expenditures required to comply with existing environmental regulations may vary substantially from the above estimates because of uncertainty as to future permitting requirements by state regulators and the EPA, revisions to regulatory obligations, and varying cost of potential compliance strategies, among other things.

The following sections describe the more significant environmental statutes and regulations and environmental enforcement and remediation matters that affect or could affect our operations. The EPA periodically amends and revises its regulations and proposes amendments to regulations and guidelines, which could ultimately result in the revision of all or part of such regulations.

Clean Air Act

Federal and state laws, including the CSAPR, regulate emissions of SO2 and NOx through the reduction of emissions at their source and the use and retirement of emission allowances. In April 2022, the EPA proposed the Good Neighbor Rule of the Clean Air Act, which includes additional NOx emission reductions from power plants in Missouri, Illinois, and other states through revisions to the CSAPR. In January 2023, the EPA issued its final disapproval of Missouri’s proposed state implementation plan for addressing the transport of ozone under the Good Neighbor Rule of the Clean Air Act. The disapproval of the state plan allows the EPA to implement revisions to the CSAPR through a federal implementation plan. In March 2023, the EPA announced federal implementation plan requirements, which were subsequently published to the Federal Register in June 2023, reducing the amount of NOx allowances available for state budgets and imposing NOx emission limits on electric generating units for Missouri, Illinois, and other states under the Good Neighbor Rule of the Clean Air Act. In April 2023, the Missouri Attorney General and Ameren Missouri separately filed lawsuits in the United States Court of Appeals for the Eighth Circuit challenging the EPA’s disapproval of the Missouri state plan and sought a stay of the EPA’s disapproval of the Missouri state plan. The United States Court of Appeals for the Eighth Circuit in May 2023 granted those stay motions thereby preventing the EPA from imposing the federal implementation plan until the court of appeals issues a ruling. In June 2024, the United States Supreme Court granted applications to stay the EPA’s imposition of the federal implementation plan until resolution of appellate court challenges. Ameren Missouri complies with the current CSAPR requirements by minimizing emissions through the use of low-sulfur coal, operation of two scrubbers at its Sioux Energy Center, and optimization of existing NOx air pollution control equipment. Reducing the amount of state budget NOx allowances for compliance with NOx emission limits could result in additional controls being required on Ameren Missouri’s generating units and/or the reduction of operations. Any additional costs for compliance are expected to be recovered from customers, subject to MoPSC prudence review, through the FAC or higher base rates.

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CO2 Emissions Standards

In June 2022, the United States Supreme Court issued its decision in West Virginia v. EPA, clarifying that there are limits on how the EPA may regulate greenhouse gases absent further direction from the United States Congress. The court concluded that the EPA’s proposed rules were designed to shift generation from fossil-fuel-fired power plants to renewable energy facilities, which was improper absent specific congressional authorization. In response to that ruling, in April 2024, the EPA issued a final rule that sets CO2 emission standards for existing coal-fired and new natural gas-fired power plants that relies on the adoption of carbon capture technology and/or natural gas co-firing for coal-fired power plants and carbon capture technology for new natural gas-fired power plants. Affected power plants are required to comply with the rule through a phased-in approach or retire. In July 2024, the United States Court of Appeals for the District of Columbia Circuit denied a request for stay by various stakeholders including state attorney generals and industry groups but indicated it would establish an expedited schedule regarding the legal merits of the final rule. Subsequently in July 2024, motions for stay of the final rule were filed with the United States Supreme Court. Ameren and Ameren Missouri are monitoring the legal challenges and assessing the impacts of the final rule and, at this time, cannot predict the impacts on their results of operations, financial position, and liquidity.

MATS

In April 2024, the EPA revised the MATS by establishing a more stringent standard for emissions of particulate matter, requiring the use of continuous emissions monitoring systems. Ameren and Ameren Missouri are assessing the impacts of the revised rule and, at this time, cannot predict the impacts on their results of operations, financial position, and liquidity.

NSR and Clean Air Act Litigation

In January 2011, the United States 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 alleging that projects performed in 2007 and 2010 at the coal-fired Rush Island Energy Center violated provisions of the Clean Air Act and Missouri law. In January 2017, the district court issued a liability ruling against Ameren Missouri and, in September 2019, entered a remedy order that required Ameren Missouri to install a flue gas desulfurization system at the Rush Island Energy Center and a dry sorbent injection system at the Labadie Energy Center. Following an appeal from Ameren Missouri, in August 2021, the United States Court of Appeals for the Eighth Circuit affirmed the liability ruling and the district court’s remedy order as it related to the installation of a flue gas desulfurization system at the Rush Island Energy Center, but reversed the order as it related to the installation of a dry sorbent injection system at the Labadie Energy Center. In September 2023, the district court granted Ameren Missouri’s request to modify the remedy order to allow the retirement of the Rush Island Energy Center in advance of its previously expected retirement date of 2039 in lieu of installing a flue gas desulfurization system. In its amended remedy order, the district court established an October 15, 2024 retirement date to allow for the completion of various transmission reliability projects and, in the interim, authorized Ameren Missouri to operate the energy center only as needed and as directed by the MISO. The United States Department of Justice is seeking an order from the district court providing for additional mitigation relief related to prior emissions. Ameren Missouri contends that the retirement of the Rush Island Energy Center, which eliminates all future emissions from the energy center, mitigates claims relating to prior emissions. In March 2024, the district court ordered Ameren Missouri and the United States Department of Justice to file proposed draft orders outlining additional mitigation relief. In May 2024, Ameren Missouri filed a proposed draft order that includes retiring the Rush Island Energy Center, a program to provide electric buses and charging stations to schools in the metro St. Louis area, a program to provide air filters to eligible Ameren Missouri electric residential customers, and the retirement of SO2 allowances. Excluding the accelerated retirement of the Rush Island Energy Center, these programs are estimated to cost approximately $20 million. Also in May 2024, the United States Department of Justice filed a proposed draft order that includes a program to provide electric buses and charging stations to schools in the metro St. Louis area and a program to provide air filters to eligible Ameren Missouri electric residential customers. These programs include a significantly greater number of buses, charging stations, and air filters than Ameren Missouri’s proposal and the United States Department of Justice estimates these programs would cost approximately $120 million. A mediation proceeding related to the potential additional mitigation relief is scheduled for September 2024. As of June 30, 2024, Ameren and Ameren Missouri recorded a $20 million liability in “Other current liabilities” on their consolidated balance sheets related to the cost of potential additional mitigation, which represents the estimated minimum liability, as no other amount within the range was a better estimate. Ameren Missouri could be required to implement some or all of the additional mitigation relief programs included in the United States Department of Justice’s proposed draft order, the costs of which could be material and could adversely impact Ameren and Ameren Missouri’s results of operations and financial position. Depending on the scope and basis of any final order issued by the district court, which is expected by the end of 2024, Ameren Missouri or the United States Department of Justice could appeal any additional mitigation relief ordered.

The MISO designated the Rush Island Energy Center as a system support resource in 2022 and concluded that certain reliability mitigation measures, including transmission upgrades, should occur before the energy center is retired. The Rush Island Energy Center began operating as a system support resource on September 1, 2022. In 2024, the MISO extended the system support resource designation through Rush Island Energy Center’s retirement date of October 15, 2024. In July 2024, an agreement between Ameren Missouri and the MISO was filed with the FERC for approval regarding the continued operation of the energy center during peak demand times and emergencies. Construction activities are ongoing for the transmission upgrades approved by the MISO, with the majority of the upgrades

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expected to be completed in the fall of 2024. Ameren Missouri expects to complete the last of the necessary upgrades by mid-2025. Related to this matter, in February 2022, the MoPSC issued an order directing the MoPSC staff to review the planned accelerated retirement of the Rush Island Energy Center. See Note 2 – Rate and Regulatory Matters Part II, Item 8, of the Form 10-K for additional information.

In connection with the accelerated retirement of the Rush Island Energy Center, the MoPSC issued an order in June 2024 authorizing Ameren Missouri to finance the costs associated with the retirement, including the remaining unrecovered net plant balance associated with the facility, through the issuance of securitized utility tariff bonds pursuant to Missouri’s securitization statute. Costs associated with the retirement would exclude any additional mitigation relief ordered in the NSR and Clean Air Act litigation discussed above. See Note 2 – Rate and Regulatory Matters for additional information. As of June 30, 2024, the Rush Island Energy Center had a net plant balance of $508 million included in plant to be abandoned, net, within “Property, Plant, and Equipment, Net”. See Note 1 – Summary of Significant Accounting Policies under Part II, Item 8, of the Form 10-K for additional information regarding plant to be abandoned, net.

Clean Water Act

Among other items, the Clean Water Act requires power plant operators to evaluate cooling water intake structures and identify measures for reducing the number of 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 this cooling water intake structures rule. Requirements of the rule are implemented by state regulators through the permit renewal process of each power plant’s water discharge permit. Permits for Ameren Missouri’s coal-fired and nuclear energy centers have been issued or are in the process of renewal.

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, prohibit effluent discharges of certain waste streams, and impose more stringent limitations on certain water discharges from power plants by 2025. To comply with these guidelines, Ameren Missouri installed dry ash handling systems and wastewater treatment facilities at its coal-fired energy centers. In April 2024, the EPA issued new effluent limitation guidelines that established a zero discharge limit for flue gas desulfurization wastewater, bottom ash transport water, and combustion residual leachate. Ameren and Ameren Missouri expect the impacts of the new guidelines on their results of operations, financial position, and liquidity to be immaterial.

CCR Management

The EPA’s 2015 CCR Rule establishes requirements for the management and disposal of CCR from coal-fired power plants and has resulted in the closure of surface impoundments at Ameren Missouri’s energy centers, with closures of surface impoundments in process at its Sioux Energy Center and retired Meramec Energy Center. Ameren Missouri plans to substantially complete the closures of remaining surface impoundments by the end of 2026. Ameren Missouri’s CCR management compliance plan includes installation of groundwater monitoring equipment and groundwater treatment facilities. In April 2024, the EPA revised the CCR Rule to impose groundwater monitoring, and corrective action, closure, and post-closure requirements on certain active and inactive CCR surface impoundments and management disposal units. Ameren and Ameren Missouri have AROs of $42 million associated with CCR storage facilities recorded on their respective balance sheets as of June 30, 2024. This amount includes an immaterial incremental ARO related to the 2024 CCR Rule, which will be revised as additional site studies are performed. Ameren and Ameren Missouri are assessing the impacts of this rule revision and, at this time, cannot predict the final impacts on their results of operations, financial position, and liquidity.

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.

As of June 30, 2024, Ameren Illinois has remediated the majority of the 44 former MGP sites in Illinois with an estimated remaining obligation primarily related to three of these former MGP sites at $45 million to $95 million. Ameren and Ameren Illinois recorded a liability of $45 million to represent the estimated minimum obligation for these sites, as no other amount within the range was a better estimate. Ameren cannot estimate the completion date of the estimated remaining obligation due to site accessibility, among other things.

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 actual costs, including unanticipated underground structures, the degree to which groundwater is impacted, regulatory changes, local ordinances, and site accessibility. The actual costs and timing of completion may vary substantially from these estimates.

The ICC allows Ameren Illinois to recover MGP remediation and related litigation costs from its electric and natural gas utility customers through environmental cost riders that are subject to annual prudence reviews by the ICC.

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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 historical practices will result in future environmental commitments, including additional or more stringent cleanup standards, or will affect our results of operations, financial position, or liquidity.

NOTE 10 – CALLAWAY ENERGY CENTER

See Note 9 – Callaway Energy Center under Part II, Item 8, of the Form 10-K for information regarding spent nuclear fuel recovery, recovery of decommissioning costs, and the nuclear decommissioning trust fund. 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. 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 December 2023 and is reflected within the ARO. Ameren Missouri’s filing supported no change in electric service rates for decommissioning costs. There is no deadline by which the MoPSC must issue an order regarding the filing. See Note 13 – Supplemental Information for more information on Ameren Missouri’s AROs.

Insurance

The following table presents insurance coverage at Ameren Missouri’s Callaway Energy Center at April 1, 2024:

Type and Source of Coverage	Most Recent Renewal Date	Maximum Coverages			Maximum Assessments for Single Incidents
Public liability and nuclear worker liability:
American Nuclear Insurers	January 1, 2024	$	500		$	—
Pool participation	(a)	15,763		(a)	166		(b)
		$	16,263	(c)	$	166
Property damage:
NEIL and EMANI	April 1, 2024	$	3,200	(d)	$	28	(e)
Accidental outage:
NEIL	April 1, 2024	$	490	(f)	$	11	(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 $500 million in the event of an incident at any licensed United States commercial reactor, payable at $24.7 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 power reactors.

(d)NEIL provides $2.7 billion in property damage, stabilization, decontamination, and premature decommissioning insurance for radiation events and $0.7 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)Accidental outage insurance provides for lost sales 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 $291 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 October 2023. 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, resulting from terrorist attacks. 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 insurance limits, 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.

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NOTE 11 – RETIREMENT BENEFITS

The following table presents the components of the net periodic benefit cost (income) incurred for Ameren’s pension and postretirement benefit plans for the three and six months ended June 30, 2024 and 2023:

	Pension Benefits								Postretirement Benefits
	Three Months				Six Months				Three Months				Six Months
	2024		2023		2024		2023		2024		2023		2024		2023
Service cost(a)	$	23	$	23	$	44	$	46	$	3	$	3	$	6	$	6
Non-service cost components:
Interest cost	56		56		111		111		11		12		22		23
Expected return on plan assets(b)	(82)		(84)		(164)		(167)		(23)		(23)		(46)		(46)
Amortization of(b):
Prior service benefit	—		—		—		—		(1)		(1)		(2)		(2)
Actuarial (gain)	(16)		(28)		(33)		(57)		(10)		(12)		(20)		(23)
Total non-service cost components(c)	$	(42)	$	(56)	$	(86)	$	(113)	$	(23)	$	(24)	$	(46)	$	(48)
Net periodic benefit income(d)	$	(19)	$	(33)	$	(42)	$	(67)	$	(20)	$	(21)	$	(40)	$	(42)

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

(b)Prior service benefit is amortized on a straight-line basis over the average future service of active participants benefiting under a plan amendment. Net actuarial gains or losses related to the net benefit obligation subject to amortization are amortized on a straight-line basis over 10 years. The difference between the actual and expected return on plan assets is amortized over 4 years.

(c)Non-service cost components are reflected in “Other Income, Net” on Ameren’s consolidated statement of income. See Note 5 – Other Income, Net for additional information.

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

Ameren Missouri and Ameren Illinois are responsible for their respective share of Ameren’s pension and other postretirement costs. The following table presents the respective share of net periodic pension and other postretirement benefit costs (income) incurred for the three and six months ended June 30, 2024 and 2023:

	Pension Benefits								Postretirement Benefits
	Three Months				Six Months				Three Months				Six Months
	2024		2023		2024		2023		2024		2023		2024		2023
Ameren Missouri(a)	$	(10)	$	(17)	$	(22)	$	(35)	$	(7)	$	(7)	$	(14)	$	(15)
Ameren Illinois	(8)		(13)		(17)		(27)		(13)		(14)		(26)		(27)
Other	(1)		(3)		(3)		(5)		—		—		—		—
Ameren(a)	$	(19)	$	(33)	$	(42)	$	(67)	$	(20)	$	(21)	$	(40)	$	(42)

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

34

NOTE 12 – INCOME TAXES

The following table presents a reconciliation of the federal statutory corporate income tax rate to the effective income tax rate for the three and six months ended June 30, 2024 and 2023:

	Ameren				Ameren Missouri				Ameren Illinois
	2024		2023		2024		2023		2024		2023
Three Months
Federal statutory corporate income tax rate	21	%	21	%	21	%	21	%	21	%	21	%
Increases (decreases) from:
Amortization of excess deferred taxes(a)	(8)		(7)		(14)		(15)		(4)		(2)
Renewable and other tax credits(b)	(4)		(5)		(8)		(10)		—		—
State tax	5		5		3		3		7		7
Depreciation differences	(1)		—		(1)		—		—		(1)
Effective income tax rate	13	%	14	%	1	%	(1)	%	24	%	25	%
Six Months
Federal statutory corporate income tax rate	21	%	21	%	21	%	21	%	21	%	21	%
Increases (decreases) from:
Amortization of excess deferred taxes(a)	(8)		(8)		(14)		(15)		(4)		(2)
Renewable and other tax credits(b)	(4)		(4)		(8)		(10)		—		—
State tax	5		5		3		3		7		7
Depreciation differences	—		—		—		—		—		(1)
Other permanent items	—		(1)		—		—		—		—
Effective income tax rate	14	%	13	%	2	%	(1)	%	24	%	25	%

(a)Reflects the amortization of amounts resulting from the revaluation of deferred income taxes subject to regulatory ratemaking, which are being refunded to customers. Deferred income taxes are revalued when federal or state income tax rates change, and the offset to the revaluation of deferred income taxes subject to regulatory ratemaking is recorded to a regulatory asset or liability.

(b)The benefit of the credits associated with Missouri renewable energy standard compliance is refunded to customers through the RESRAM.

NOTE 13 – SUPPLEMENTAL INFORMATION

Cash, Cash Equivalents, and Restricted Cash

The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the balance sheets and the statements of cash flows at June 30, 2024, and December 31, 2023:

	June 30, 2024						December 31, 2023
	Ameren		Ameren Missouri		Ameren Illinois		Ameren		Ameren Missouri		Ameren Illinois
“Cash and cash equivalents”	$	19	$	—	$	6	$	25	$	—	$	—
Restricted cash included in “Other current assets”	18		7		7		13		5		5
Restricted cash included in “Other assets”	260		—		260		229		—		229
Restricted cash included in “Nuclear decommissioning trust fund”	4		4		—		5		5		—
Total cash, cash equivalents, and restricted cash	$	301	$	11	$	273	$	272	$	10	$	234

Restricted cash included in “Other current assets” primarily represents funds held by an irrevocable Voluntary Employee Beneficiary Association (VEBA) trust, which provides health care benefits for active employees. Restricted cash included in “Other assets” on Ameren’s and Ameren Illinois’ balance sheets primarily represents amounts collected under a cost recovery rider restricted for use in the procurement of renewable energy credits and amounts in a trust fund restricted for the use of funding certain asbestos-related claims.

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 June 30, 2024, and December 31, 2023, “Other current liabilities” on Ameren’s and Ameren Illinois’ balance sheets included payables for purchased receivables of $49 million and $42 million, respectively.

35

The following table provides a reconciliation of the beginning and ending amount of the allowance for doubtful accounts for the three and six months ended June 30, 2024 and 2023:

	Three Months				Six Months
	2024		2023		2024		2023
Ameren:
Beginning of period	$	37	$	34	$	30	$	31
Bad debt expense	6		13		16		23
Charged to other accounts(a)	1		1		4		1
Net write-offs	(7)		(9)		(13)		(16)
End of period	$	37	$	39	$	37	$	39
Ameren Missouri:
Beginning of period	$	11	$	12	$	12	$	13
Bad debt expense	4		2		5		4
Net write-offs	(3)		(2)		(5)		(5)
End of period	$	12	$	12	$	12	$	12
Ameren Illinois:(b)
Beginning of period	$	26	$	22	$	18	$	18
Bad debt expense	2		11		11		19
Charged to other accounts(a)	1		1		4		1
Net write-offs	(4)		(7)		(8)		(11)
End of period	$	25	$	27	$	25	$	27

(a)Amounts associated with the allowance for doubtful accounts related to receivables purchased by Ameren Illinois from alternative retail electric suppliers, as required by the Illinois Public Utilities Act.

(b)Ameren Illinois has rate-adjustment mechanisms that allow it to recover the difference between its actual net bad debt write-offs under GAAP, including those associated with receivables purchased from alternative retail electric suppliers, and the amount of net bad debt write-offs included in its base rates. The table above does not include the impact related to the riders.

Supplemental Cash Flow Information

The following table provides noncash financing and investing activity excluded from the statements of cash flows for the six months ended June 30, 2024 and 2023:

	June 30, 2024						June 30, 2023
	Ameren		Ameren Missouri		Ameren Illinois		Ameren		Ameren Missouri		Ameren Illinois
Investing:
Accrued capital expenditures, including nuclear fuel expenditures	$	380	$	232	$	134	$	325	$	132	$	173
Net realized and unrealized gain – nuclear decommissioning trust fund	103		103		—		105		105		—
Return of investment in industrial development revenue bonds(a)	—		—		—		240		240		—
Financing:
Issuance of common stock for stock-based compensation	$	16	$	—	$	—	$	37	$	—	$	—
Issuance of common stock under the DRPlus	7		—		—		7		—		—
Termination of a financing obligation(a)	—		—		—		240		240		—

(a)In January 2023, Ameren Missouri and Audrain County mutually agreed to terminate a financing obligation agreement related to the CT energy center in Audrain County, which was scheduled to expire in December 2023. No cash was exchanged in connection with the termination of the agreement as the $240 million principal amount of the financing obligation due from Ameren Missouri was equal to the amount of bond service payments due to Ameren Missouri.

36

Asset Retirement Obligations

The following table provides a reconciliation of the beginning and ending carrying amount of AROs for the six months ended June 30, 2024:

	Ameren Missouri			Ameren Illinois			Ameren
Balance at December 31, 2023	$	787	(a)	$	4	(b)	$	791	(a)
Liabilities incurred	7		(c)	—			7		(c)
Liabilities settled	(4)			(1)			(5)
Accretion	17		(d)	—			17		(d)
Balance at June 30, 2024	$	807	(a)	$	3	(b)	$	810	(a)

(a)Balance included $19 million in “Other current liabilities” on the balance sheet as of both June 30, 2024, and December 31, 2023.

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

(c)In June 2024, Ameren and Ameren Missouri recorded an ARO related to the decommissioning for the Cass County Solar Project. In addition, as a result of the 2024 CCR Rule, Ameren and Ameren Missouri recorded an immaterial increase to their AROs associated with CCR storage facilities. See Note 9 – Commitments and Contingencies for additional information.

(d)Accretion expense attributable to Ameren Missouri was recorded as a decrease to regulatory liabilities.

Stock-based Compensation

In the first quarter of 2024, Ameren granted 359,133 performance share units with a grant date fair value of $21 million and 153,887 restricted share units with a grant date fair value of $11 million. Awards vest approximately 3 years after the grant date based on continued employment or on a pro-rata basis upon death or eligible retirement. The performance share units vest based on the achievement of certain specified market performance measures (307,816 performance share units) or clean energy transition targets (51,317 performance share units). The exact number of shares issued pursuant to a performance share unit varies from 0% to 200% of the target award, depending on actual company performance relative to the performance goals.

For the six months ended June 30, 2024 and 2023, excess tax benefits (deficiencies) associated with the settlement of stock-based compensation awards increased income tax expense by $1 million and reduced income tax expense by $6 million, respectively.

Deferred Compensation

At June 30, 2024, and December 31, 2023, the present value of benefits to be paid for deferred compensation obligations was $80 million and $85 million, respectively, which was primarily reflected in “Other deferred credits and liabilities” on Ameren’s consolidated balance sheet.

Operating Revenues

As of June 30, 2024 and 2023, our remaining performance obligations for contracts with a term greater than one year were immaterial. 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.

See Note 14 – Segment Information for disaggregated revenue information.

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 three and six months ended June 30, 2024 and 2023:

	Three Months				Six Months
	2024		2023		2024		2023
Ameren Missouri	$	41	$	39	$	76	$	73
Ameren Illinois	28		26		65		63
Ameren	$	69	$	65	$	141	$	136

37

Earnings per Share

The following table reconciles the basic weighted-average number of common shares outstanding to the diluted weighted-average number of common shares outstanding for the three and six months ended June 30, 2024 and 2023:

	Three Months		Six Months
	2024	2023	2024	2023
Weighted-average Common Shares Outstanding – Basic	266.7	262.6	266.5	262.4
Assumed settlement of performance share units and restricted stock units	0.1	0.6	0.3	0.8
Weighted-average Common Shares Outstanding – Diluted(a)	266.8	263.2	266.8	263.2

(a)There was an immaterial number of anti-dilutive performance share units excluded from the earnings per diluted share calculations for the three and six months ended June 30, 2024 and 2023. The outstanding forward sale agreements as of June 30, 2024 and 2023, were anti-dilutive for the three and six months ended June 30, 2024 and 2023, and were excluded from the earnings per diluted share calculation as calculated using the treasury stock method. For additional information about the outstanding forward sale agreements, see Note 4 – Long-term Debt and Equity Financings.

NOTE 14 – SEGMENT INFORMATION

The following tables present revenues, net income attributable to common shareholders, and capital expenditures by segment at Ameren and Ameren Illinois for the three and six months ended June 30, 2024 and 2023. Ameren, Ameren Missouri, and Ameren Illinois management review segment capital expenditure information rather than any individual or total asset amount. For additional information about our segments, see Note 16 – Segment Information under Part II, Item 8, of the Form 10-K.

Ameren

	Ameren Missouri		Ameren Illinois Electric Distribution		Ameren Illinois Natural Gas		Ameren Transmission			Other		Intersegment Eliminations		Ameren
Three Months 2024:
External revenues	$	879	$	509	$	148	$	157		$	—	$	—	$	1,693
Intersegment revenues	9		—		—		34			—		(43)		—
Net income (loss) attributable to Ameren common shareholders	128		61		6		79		(a)	(16)		—		258
Capital expenditures	638		132		59		175			2		(4)		1,002
Three Months 2023:
External revenues	$	933	$	540	$	152	$	135		$	—	$	—	$	1,760
Intersegment revenues	8		—		—		26			—		(34)		—
Net income (loss) attributable to Ameren common shareholders	102		66		11		72		(a)	(14)		—		237
Capital expenditures	433		180		90		197			2		(11)		891
Six Months 2024:
External revenues	$	1,647	$	1,015	$	539	$	308		$	—	$	—	$	3,509
Intersegment revenues	16		—		—		68			—		(84)		—
Net income (loss) attributable to Ameren common shareholders	153		117		112		151		(a)	(14)		—		519
Capital expenditures	1,104		316		119		341			4		8		1,892
Six Months 2023:
External revenues	$	1,846	$	1,164	$	543	$	269		$	—	$	—	$	3,822
Intersegment revenues	18		—		—		55			—		(73)		—
Net income attributable to Ameren common shareholders	130		127		98		143		(a)	3		—		501
Capital expenditures	914		350		141		410			5		2		1,822

(a)Ameren Transmission earnings reflect an allocation of financing costs from Ameren (parent).

38

Ameren Illinois

	Ameren Illinois Electric Distribution		Ameren Illinois Natural Gas		Ameren Illinois Transmission		Intersegment Eliminations		Ameren Illinois
Three Months 2024:
External revenues	$	509	$	148	$	109	$	—	$	766
Intersegment revenues	—		—		27		(27)		—
Net income available to common shareholder	61		6		57		—		124
Capital expenditures	132		59		153		—		344
Three Months 2023:
External revenues	$	540	$	152	$	87	$	—	$	779
Intersegment revenues	—		—		26		(26)		—
Net income available to common shareholder	66		11		52		—		129
Capital expenditures	180		90		167		—		437
Six Months 2024:
External revenues	$	1,015	$	539	$	212	$	—	$	1,766
Intersegment revenues	—		—		55		(55)		—
Net income available to common shareholder	117		112		110		—		339
Capital expenditures	316		119		282		—		717
Six Months 2023:
External revenues	$	1,164	$	543	$	173	$	—	$	1,880
Intersegment revenues	—		—		54		(54)		—
Net income available to common shareholder	127		98		102		—		327
Capital expenditures	350		141		353		—		844

The following tables present disaggregated revenues by segment at Ameren and Ameren Illinois for the three and six months ended June 30, 2024 and 2023. 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, off-system sales, and capacity revenues.

Ameren

	Ameren Missouri		Ameren Illinois Electric Distribution			Ameren Illinois Natural Gas		Ameren Transmission		Intersegment Eliminations		Ameren
Three Months 2024:
Residential	$	395	$	311		$	—	$	—	$	—	$	706
Commercial	324		163			—		—		—		487
Industrial	77		47			—		—		—		124
Other	68		(12)		(a)	—		191		(43)		204
Total electric revenues	$	864	$	509		$	—	$	191	$	(43)	$	1,521
Residential	$	13	$	—		$	102	$	—	$	—	$	115
Commercial	5		—			24		—		—		29
Industrial	1		—			1		—		—		2
Other	5		—			21		—		—		26
Total natural gas revenues	$	24	$	—		$	148	$	—	$	—	$	172
Total revenues(b)	$	888	$	509		$	148	$	191	$	(43)	$	1,693

39

	Ameren Missouri		Ameren Illinois Electric Distribution			Ameren Illinois Natural Gas		Ameren Transmission		Intersegment Eliminations		Ameren
Three Months 2023:
Residential	$	360	$	337		$	—	$	—	$	—	$	697
Commercial	311		193			—		—		—		504
Industrial	75		48			—		—		—		123
Other	172		(38)		(a)	—		161		(34)		261
Total electric revenues	$	918	$	540		$	—	$	161	$	(34)	$	1,585
Residential	$	13	$	—		$	98	$	—	$	—	$	111
Commercial	6		—			25		—		—		31
Industrial	1		—			2		—		—		3
Other	3		—			27		—		—		30
Total natural gas revenues	$	23	$	—		$	152	$	—	$	—	$	175
Total revenues(b)	$	941	$	540		$	152	$	161	$	(34)	$	1,760
Six Months 2024:
Residential	$	736	$	608		$	—	$	—	$	—	$	1,344
Commercial	583		328			—		—		—		911
Industrial	138		92			—		—		—		230
Other	121		(13)		(a)	—		376		(84)		400
Total electric revenues	$	1,578	$	1,015		$	—	$	376	$	(84)	$	2,885
Residential	$	53	$	—		$	389	$	—	$	—	$	442
Commercial	21		—			92		—		—		113
Industrial	3		—			5		—		—		8
Other	8		—			53		—		—		61
Total natural gas revenues	$	85	$	—		$	539	$	—	$	—	$	624
Total revenues(b)	$	1,663	$	1,015		$	539	$	376	$	(84)	$	3,509
Six Months 2023:
Residential	$	684	$	719		$	—	$	—	$	—	$	1,403
Commercial	558		393			—		—		—		951
Industrial	136		96			—		—		—		232
Other	381		(44)		(a)	—		324		(72)		589
Total electric revenues	$	1,759	$	1,164		$	—	$	324	$	(72)	$	3,175
Residential	$	65	$	—		$	394	$	—	$	—	$	459
Commercial	29		—			102		—		—		131
Industrial	3		—			9		—		—		12
Other	8		—			38		—		(1)		45
Total natural gas revenues	$	105	$	—		$	543	$	—	$	(1)	$	647
Total revenues(b)	$	1,864	$	1,164		$	543	$	324	$	(73)	$	3,822

40

(a)Includes over-recoveries of various riders.

(b)The following table presents increases/(decreases) in revenues from alternative revenue programs and other revenues not from contracts with customers for the three and six months ended June 30, 2024 and 2023:

	Ameren Missouri			Ameren Illinois Electric Distribution		Ameren Illinois Natural Gas		Ameren Transmission		Ameren
Three Months 2024:
Revenues from alternative revenue programs	$	(1)		$	22	$	—	$	4	$	25
Other revenues not from contracts with customers	1			1		1		—		3
Three Months 2023:
Revenues from alternative revenue programs	$	—		$	60	$	9	$	5	$	74
Other revenues not from contracts with customers	(2)		(a)	2		1		—		1		(a)
Six Months 2024:
Revenues from alternative revenue programs	$	(7)		$	61	$	19	$	13	$	86
Other revenues not from contracts with customers	2			3		2		—		7
Six Months 2023:
Revenues from alternative revenue programs	$	(2)		$	124	$	37	$	13	$	172
Other revenues not from contracts with customers	(8)		(a)	4		2		—		(2)		(a)

(a)Includes net realized losses on derivative power contracts.

Ameren Illinois

	Ameren Illinois Electric Distribution			Ameren Illinois Natural Gas		Ameren Illinois Transmission		Intersegment Eliminations		Ameren Illinois
Three Months 2024:
Residential	$	311		$	102	$	—	$	—	$	413
Commercial	163			24		—		—		187
Industrial	47			1		—		—		48
Other	(12)		(a)	21		136		(27)		118
Total revenues(b)	$	509		$	148	$	136	$	(27)	$	766
Three Months 2023:
Residential	$	337		$	98	$	—	$	—	$	435
Commercial	193			25		—		—		218
Industrial	48			2		—		—		50
Other	(38)		(a)	27		113		(26)		76
Total revenues(b)	$	540		$	152	$	113	$	(26)	$	779
Six Months 2024:
Residential	$	608		$	389	$	—	$	—	$	997
Commercial	328			92		—		—		420
Industrial	92			5		—		—		97
Other	(13)		(a)	53		267		(55)		252
Total revenues(b)	$	1,015		$	539	$	267	$	(55)	$	1,766
Six Months 2023:
Residential	$	719		$	394	$	—	$	—	$	1,113
Commercial	393			102		—		—		495
Industrial	96			9		—		—		105
Other	(44)		(a)	38		227		(54)		167
Total revenues(b)	$	1,164		$	543	$	227	$	(54)	$	1,880

41

(a)Includes over-recoveries of various riders.

(b)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 three and six months ended June 30, 2024 and 2023:

	Ameren Illinois Electric Distribution		Ameren Illinois Natural Gas		Ameren Illinois Transmission		Ameren Illinois
Three Months 2024:
Revenues from alternative revenue programs	$	22	$	—	$	2	$	24
Other revenues not from contracts with customers	1		1		—		2
Three Months 2023:
Revenues from alternative revenue programs	$	60	$	9	$	3	$	72
Other revenues not from contracts with customers	2		1		—		3
Six Months 2024:
Revenues from alternative revenue programs	$	61	$	19	$	10	$	90
Other revenues not from contracts with customers	3		2		—		5
Six Months 2023:
Revenues from alternative revenue programs	$	124	$	37	$	10	$	171
Other revenues not from contracts with customers	4		2		—		6

ITEM 2. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS.

The following discussion should be read in conjunction with the financial statements contained in this Form 10-Q, as well as Management’s Discussion and Analysis of Financial Condition and Results of Operations and Risk Factors contained in the Form 10-K. We intend for this discussion to provide the reader with information that will assist in understanding our financial statements, the changes in certain key items in those financial statements, and the primary factors that accounted for those changes, as well as how certain accounting principles affect our financial statements. The discussion also provides information about the financial results of our business segments to provide a better understanding of how those segments and their results affect the financial condition and results of operations of Ameren as a whole. Also see the Glossary of Terms and Abbreviations at the front of this report and in the Form 10-K.

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.

•Ameren Missouri operates a rate-regulated electric generation, transmission, and distribution business and a rate-regulated natural gas distribution business in Missouri.

•Ameren Illinois operates rate-regulated electric transmission, electric distribution, and natural gas distribution businesses in Illinois.

•ATXI operates a FERC rate-regulated electric transmission business in the MISO.

Ameren’s and Ameren Missouri’s financial statements are prepared on a consolidated basis and therefore include the accounts of their majority-owned subsidiaries. All intercompany transactions have been eliminated. Ameren Missouri’s subsidiaries were created for the ownership of renewable generation projects. Ameren Illinois has no subsidiaries. All tabular dollar amounts are in millions, unless otherwise indicated.

In addition to presenting results of operations and earnings amounts in total, we present certain information in cents per share. These amounts reflect factors that directly affect Ameren’s earnings. We believe this per share information helps readers to understand the impact of these factors on Ameren’s earnings per share.

OVERVIEW

Net income attributable to Ameren common shareholders in the three months ended June 30, 2024, was $258 million, or $0.97 per diluted share, compared with $237 million, or $0.90 per diluted share, in the year-ago period. Net income attributable to Ameren common shareholders in the six months ended June 30, 2024, was $519 million, or $1.95 per diluted share, compared with $501 million, or $1.90 per diluted share, in the year-ago period. Net income for the three and six months ended June 30, 2024, were favorably affected by increased base rate revenues pursuant to the MoPSC's June 2023 electric rate order; increased retail electric sales at Ameren Missouri, primarily due to warmer spring and early summer temperatures in 2024; and increased deferral of financing costs associated with rate base investments at Ameren Missouri. Earnings for the three and six months ended June 30, 2024, were also favorably affected by increased rate base investments at Ameren Transmission. Net income for the six months ended June 30, 2024, was favorably affected by higher base rate revenues pursuant to the ICC's November 2023 natural gas rate order, which increased earnings at Ameren Illinois Natural Gas. Net income for the three and six months ended June 30, 2024, were unfavorably affected by increased other operations and maintenance expenses not

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subject to formula rates, riders, or trackers, including a charge recorded by Ameren Missouri related to a change in the estimated minimum cost of additional mitigation relief associated with NSR and Clean Air Act litigation applicable to the Rush Island Energy Center for the six months ended June 30, 2024. Earnings for the three and six months ended June 30, 2024, were also unfavorably affected by increased financing costs due to higher long-term debt balances and interest rates and a lower recognized ROE under the MYRP. In addition, an increase in the weighted-average basic common shares outstanding reduced earnings per diluted share.

Ameren’s strategic plan includes investing in rate-regulated energy infrastructure, enhancing regulatory frameworks and advocating for responsible policies, and optimizing operating performance to capitalize on opportunities to benefit our customers, communities, shareholders, and the environment. Ameren remains focused on disciplined cost management and strategic capital allocation. Ameren invested $1.9 billion in its rate-regulated businesses in the six months ended June 30, 2024.

In June 2024, Ameren Missouri filed a request with the MoPSC seeking approval to increase its annual revenues for electric service by $446 million. The electric rate increase request is based on a 10.25% return on common equity, a capital structure composed of 52% common equity, a rate base of $14 billion, and a test year ended March 31, 2024, with certain pro-forma adjustments expected through an anticipated true-up date of December 31, 2024. The MoPSC proceeding relating to the proposed electric service rate changes will take place over a period of up to 11 months, with a decision by the MoPSC expected by May 2025 and new rates effective by June 2025.

In June 2024, the MoPSC issued a financing order authorizing the issuance of securitized utility tariff bonds by a wholly owned, special purpose subsidiary of Ameren Missouri to finance approximately $470 million of costs related to the planned accelerated retirement of the Rush Island Energy Center, which includes the expected remaining unrecovered net plant balance associated with the facility, among other costs. Ameren Missouri initially petitioned the MoPSC in November 2023 to finance $519 million of costs. The difference between the initial petition and final financing order will be considered for recovery in future rate proceedings involving the securitized utility tariff charge or base rates. Ameren Missouri will collect the amounts necessary to repay the bonds over approximately 15 years from the date of bond issuance. The financing order also includes a determination that the decision to retire the Rush Island Energy Center was reasonable and prudent. The MoPSC did not make a determination regarding the prudency of Ameren Missouri's prior actions that resulted in the adverse ruling in the NSR and Clean Air Act litigation discussed in Note 9 – Commitments and Contingencies under Part I, Item 1, of this report. However, claims regarding such actions could be considered in future regulatory proceedings. If future regulatory proceedings result in revenue reductions based on Ameren Missouri’s prior actions that resulted in the adverse ruling in the NSR and Clean Air Act litigation, it could have a material adverse effect on the results of operations, financial position, and liquidity of Ameren and Ameren Missouri. In July 2024, the MoOPC filed a request for rehearing of the financing order. Ameren Missouri expects a decision on the rehearing request in August 2024. The decision on the rehearing request is subject to appeal. The timing of the issuance of securitized utility tariff bonds is dependent on the conclusion of any appeal process.

In June 2024, the MoPSC issued an order approving a requested CCN for the Cass County Solar Project and Ameren Missouri acquired the project, which includes solar panels, project design, land rights, and engineering, procurement, and construction agreements, for approximately $250 million and took over construction management of the project. Also in June 2024, Ameren Missouri filed for a CCN with the MoPSC to construct the Castle Bluff Natural Gas Project. In March 2024, the MoPSC issued an order approving requested CCNs for the Split Rail, Vandalia, and Bowling Green solar projects. In February and April 2023, the MoPSC issued orders approving requested CCNs for the Huck Finn and Boomtown solar projects, respectively.

In February 2024, Ameren Missouri filed an update to its Smart Energy Plan with the MoPSC, which includes a five-year capital investment overview with a detailed one-year plan for 2024. The plan is designed to upgrade Ameren Missouri’s electric infrastructure and includes investments that will upgrade the grid and accommodate more renewable energy. Investments under the plan are expected to total approximately $12.4 billion over the five-year period from 2024 through 2028, with expenditures largely recoverable under the PISA. Ameren Missouri’s Smart Energy Plan excludes investments in its natural gas distribution business, as well as removal costs, net of salvage.

In January 2024, Ameren Missouri filed a proposed customer energy-efficiency plan with the MoPSC under the MEEIA. This filing proposed a three-year plan, which includes a portfolio of customer energy-efficiency programs, along with the continued use of the MEEIA rider, which allows Ameren Missouri to collect from customers its actual MEEIA program costs and related lost electric revenues. If the plan is approved, Ameren Missouri intends to invest $123 million annually in the proposed customer energy-efficiency programs from 2025 to 2027. In addition, Ameren Missouri requested performance incentives applicable to each plan year to earn revenues by achieving certain customer energy-efficiency savings and target spending goals. If 100% of the goals are achieved, Ameren Missouri would earn performance incentive revenues totaling $56 million over the three-year plan. Ameren Missouri also requested additional performance incentives applicable to each plan year totaling up to $14 million over the three-year plan, if Ameren Missouri exceeds 100% of the goals. In March 2024, the MoPSC staff and the MoOPC filed responses in opposition to the proposed customer energy-efficiency plan under the MEEIA. Ameren Missouri expects a decision by the MoPSC by October 2024, but cannot predict the ultimate outcome of this regulatory proceeding.

In September 2023, the United States District Court for the Eastern District of Missouri granted Ameren Missouri’s request to modify a September 2019 remedy order issued by the district court in order to allow the retirement of the Rush Island Energy Center in advance of its

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previously expected retirement date of 2039, in lieu of installing a flue gas desulfurization system. In its amended remedy order, the district court established an October 15, 2024 retirement date to allow for the completion of various transmission reliability projects and, in the interim, authorized Ameren Missouri to operate the energy center only as needed and as directed by the MISO. The United States Department of Justice is seeking an order from the district court providing for additional mitigation relief related to prior emissions. Ameren Missouri contends that the retirement of the Rush Island Energy Center, which eliminates all future emissions from the energy center, mitigates claims relating to prior emissions. In March 2024, the district court ordered Ameren Missouri and the United States Department of Justice to file proposed draft orders outlining additional mitigation relief. In May 2024, Ameren Missouri filed a proposed draft order that includes retiring the Rush Island Energy Center, a program to provide electric buses and charging stations to schools in the metro St. Louis area, a program to provide air filters to eligible Ameren Missouri electric residential customers, and the retirement of SO2 allowances. Excluding the accelerated retirement of the Rush Island Energy Center, these programs are estimated to cost approximately $20 million. Also in May 2024, the United States Department of Justice filed a proposed draft order that includes a program to provide electric buses and charging stations to schools in the metro St. Louis area and a program to provide air filters to eligible Ameren Missouri electric residential customers. These programs include a significantly greater number of buses, charging stations, and air filters than Ameren Missouri’s proposal and the United States Department of Justice estimates these programs would cost approximately $120 million. A mediation proceeding related to the potential additional mitigation relief is scheduled for September 2024. As of June 30, 2024, Ameren and Ameren Missouri recorded a $20 million liability related to the cost of potential additional mitigation, which represents the estimated minimum liability, as no other amount within the range was a better estimate. Ameren Missouri could be required to implement some or all of the additional mitigation relief programs included in the United States Department of Justice’s proposed draft order, the costs of which could be material and could adversely impact Ameren and Ameren Missouri’s results of operations and financial position. Depending on the scope and basis of any final order issued by the district court, which is expected by the end of 2024, Ameren Missouri or the United States Department of Justice could appeal any additional mitigation relief ordered.

In April 2024, Ameren Illinois filed for a reconciliation adjustment to its 2023 electric distribution service revenue requirement with the ICC. In July 2024, Ameren Illinois filed a revised reconciliation adjustment, requesting recovery of $158 million. The reconciliation adjustment reflects a capital structure composed of 50% common equity and Ameren Illinois’ actual 2023 recoverable costs and year-end rate base. An ICC decision in this proceeding is required by December 2024, and any approved adjustment would be collected from customers in 2025. This is the final revenue requirement reconciliation under the IEIMA formula framework.

In December 2023, the ICC issued an order in Ameren Illinois' MYRP proceeding approving base rates for electric distribution services for 2024 through 2027 and rejecting Ameren Illinois' Grid Plan, which was addressed as part of the MYRP proceeding. Rate changes consistent with the December 2023 order became effective in January 2024 and remained effective through late June 2024, when new rates became effective pursuant to the June 2024 ICC rehearing order discussed below. The December 2023 order adopted an alternative methodology to establish a rate base and revenue requirements for the years 2024 through 2027 using Ameren Illinois’ previously approved 2022 year-end rate base. In January 2024, the ICC partially denied a rehearing requested by Ameren Illinois to revise the allowed ROE in the December 2023 order and granted Ameren Illinois’ rehearing request to reconsider the rate base for each year of the MYRP and to include a base level of investments to maintain grid reliability in each year of the MYRP. In June 2024, the ICC issued an order on Ameren Illinois’ rehearing request, approving revenue requirements for electric distribution services for 2024, 2025, 2026, and 2027 of $1,196 million, $1,282 million, $1,350 million, and $1,397 million, respectively. New rates became effective in late June 2024. In July 2024, Ameren Illinois filed a request for rehearing of the ICC’s June 2024 rehearing order to include an asset associated with other postretirement benefits in the rate base. Subsequently, in August 2024, the ICC denied the rehearing request. The ICC rehearing denial is subject to appeal. Also, in January 2024, Ameren Illinois filed an appeal of the December 2023 ICC order, including the 8.72% ROE, to the Illinois Appellate Court for the Fifth Judicial District. The court is under no deadline to address the appeal. In July 2024, Ameren Illinois filed an update to its revised Grid Plan and a request to update the associated MYRP revenue requirements for 2024, 2025, 2026, and 2027 of $1,215 million, $1,300 million, $1,386 million, and $1,446 million, respectively. An ICC decision on the revised Grid Plan and updated revenue requirements is expected by the end of 2024 with rates effective in January 2025. Ameren Illinois cannot predict the ultimate outcome of the appeal to the Illinois Appellate Court for the Fifth Judicial District, its revised Grid Plan filing, or its request to update the associated MYRP revenue requirements for 2024 through 2027.

In November 2023, the ICC issued an order in Ameren Illinois’ January 2023 natural gas delivery service regulatory rate review, which resulted in an increase to its annual revenues for natural gas delivery service of $112 million based on a 9.44% allowed ROE, a capital structure composed of 50% common equity, and a rate base of approximately $2.85 billion. The order reflected a reduction of approximately $93 million of planned distribution and transmission capital investments included in Ameren Illinois’ requested revenue increase, which used a 2024 future test year. The new rates became effective on November 28, 2023. In December 2023, Ameren Illinois filed a request for rehearing of the ICC’s November 2023 order. The filing requested the ICC revise the order to include an allowed ROE of at least 9.89%, a capital structure composed of 52% common equity, and the reversal of the approximately $93 million reduction of planned distribution and transmission capital investments included in the order, among other things. In January 2024, the ICC denied Ameren Illinois’ rehearing request. Subsequently, in January 2024, Ameren Illinois filed an appeal of the November 2023 ICC order to the Illinois Appellate Court for the Fifth Judicial District. The court is under no deadline to address the appeal. Ameren Illinois cannot predict the ultimate outcome of this appeal.

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In May 2024, Ameren Illinois filed its annual electric energy-efficiency formula rate update to increase its rates by $26 million with the ICC. An ICC decision in this proceeding is required by December 2024, with new rates effective January 2025.

In 2021, the MISO issued a report outlining a preliminary long-range transmission planning roadmap of projects through 2039, which considers the rapidly changing generation mix within MISO resulting from significant additions of renewable generation, actual and expected generation plant closures, and state mandates or goals for clean energy or carbon emissions reductions. In July 2022, the MISO approved the first tranche of projects under the roadmap. A portion of these projects were assigned to various utilities, of which Ameren was awarded projects that are estimated to cost approximately $1.8 billion, based on the MISO’s cost estimate. Related to these projects, Ameren began substation upgrades in May 2024 in advance of transmission line construction, which is expected to begin in 2026, with forecasted completion dates near the end of this decade. In addition, MISO awarded two competitive bid projects to ATXI in the fourth quarter of 2023 and one in April 2024 that represent a total estimated investment of approximately $220 million for ATXI. In February 2024, Ameren Illinois and ATXI filed a request for a CCN, among other things, with the ICC related to the portion of the MISO long-range transmission projects they will construct within the ICC’s jurisdiction. A decision by the ICC is expected by mid-2025. In July 2024, ATXI filed a request for a CCN, among other things, with the MoPSC related to a portion of the MISO long-range transmission projects that it will construct within the MoPSC’s jurisdiction. A decision by the MoPSC is expected by mid-2025. In June 2024, the MISO revised a proposed first set of second tranche projects with estimated costs of $23 billion to $27 billion based on the MISO’s cost estimate. The MISO is expected to approve this set of projects by the end of 2024. The MISO expects to develop an additional set of second tranche projects in 2025.

For further information on the matters discussed above, see Note 2 – Rate and Regulatory Matters under Part I, Item 1, of this report, and the Outlook section below.

RESULTS OF OPERATIONS

Our results of operations and financial position are affected by many factors. Economic conditions, energy-efficiency investments by our customers and by us, technological advances, distributed generation, and the actions of key customers can significantly affect the demand for our services. Ameren and Ameren Missouri results are also affected by seasonal fluctuations in winter heating and summer cooling demands and by weather conditions, such as storms, as well as by energy center maintenance outages. Additionally, fluctuations in interest rates and conditions in the capital and credit markets affect our cost of borrowing, our pension and postretirement benefits costs, the cash surrender value of COLI, and the asset value of Ameren Missouri’s nuclear decommissioning trust fund. Almost all of Ameren’s revenues are subject to state or federal regulation. This regulation has a material impact on the rates we charge customers for our services. Our results of operations, financial position, and liquidity are affected by our ability to align our overall spending, both operating and capital, with the frameworks established by our regulators. See Note 2 – Rate and Regulatory Matters under Part I, Item 1, of this report and Note 2 – Rate and Regulatory Matters under Part II, Item 8, of the Form 10-K for additional information regarding Ameren Missouri’s, Ameren Illinois’, and ATXI’s regulatory mechanisms.

Although the pace of inflation has slowed recently, we are still observing elevated inflation levels that continue to put pressure on the prices of labor, services, materials, and supplies, as well as high interest rates. Ameren Missouri and Ameren Illinois are generally allowed to pass on to customers prudently incurred costs for fuel, purchased power, and natural gas supply. Additionally, for certain non-commodity cost changes, the use of trackers, riders, formula ratemaking, and future test years, as applicable, mitigates our exposure.

Ameren Missouri principally uses coal and enriched uranium for fuel in its electric generation operations and purchases natural gas for its customers. Ameren Illinois purchases power and natural gas for its customers. The prices for these commodities can fluctuate significantly because of the global economic and political environment, weather, supply, demand, and many other factors. We have natural gas cost recovery mechanisms for our Illinois and Missouri natural gas distribution businesses, a purchased power cost recovery mechanism for Ameren Illinois’ electric distribution business, and a FAC for Ameren Missouri’s electric business.

We employ various risk management strategies to reduce our exposure to commodity risk and other risks inherent in our business. The reliability of Ameren Missouri’s energy centers and our transmission and distribution systems, and the level and timing of operations and maintenance costs and capital investment, are key factors that we seek to manage in order to optimize our results of operations, financial position, and liquidity.

Earnings Summary

The following table presents a summary of Ameren’s earnings for the three and six months ended June 30, 2024 and 2023:

	Three Months				Six Months
	2024		2023		2024		2023
Net income attributable to Ameren common shareholders	$	258	$	237	$	519	$	501
Earnings per common share – diluted	0.97		0.90		1.95		1.90

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Net income attributable to Ameren common shareholders increased $21 million, or 7 cents per diluted share, in the three months ended June 30, 2024, compared with the year-ago period. The increase was due to net income increases of $26 million and $7 million at Ameren Missouri and Ameren Transmission, respectively. These increases were partially offset by net income decreases of $5 million and $5 million at Ameren Illinois Electric Distribution and Ameren Illinois Natural Gas, respectively, and an increase in net loss of $2 million for activity not reported as part of a segment, primarily at Ameren (parent).

Net income attributable to Ameren common shareholders increased $18 million, or 5 cents per diluted share, in the six months ended June 30, 2024, compared with the year-ago period. The increase was due to net income increases of $23 million, $14 million, and $8 million, at Ameren Missouri, Ameren Illinois Natural Gas, and Ameren Transmission, respectively. These increases were partially offset by a net income decrease of $10 million at Ameren Illinois Electric Distribution and a net loss of $14 million compared with net income of $3 million in the year-ago period, for activity not reported as part of a segment, primarily at Ameren (parent).

Earnings per diluted share were favorably affected in the three and six months ended June 30, 2024, compared to the year-ago periods (except where a specific period is referenced), by:

•increased base rate revenues at Ameren Missouri effective July 9, 2023, pursuant to the June 2023 MoPSC electric rate order, partially offset by the net effect of amortization of previously deferred depreciation expense under the PISA and RESRAM, financing costs otherwise recoverable under the PISA and RESRAM, a lower base level of expenses included in trackers, and the net recovery for amounts associated with the reduction in sales volumes resulting from MEEIA programs (5 cents and 9 cents per share, respectively);

•increased retail electric sales volumes at Ameren Missouri, primarily due to warmer spring and early summer temperatures in the three months ended June 30, 2024, and increased retail electric sales volumes, excluding the estimated effects of weather and customer energy-efficiency programs (estimated at 6 cents and 8 cents per share, respectively);

•increased rate base investments at Ameren Transmission, which increased earnings in this segment (4 cents and 7 cents per share, respectively);

•increased allowance for equity funds used during construction and increased base rate revenues for the inclusion of previously deferred PISA and RESRAM interest charges pursuant to the June 2023 MoPSC electric rate order effective July 9, 2023, partially offset by increased interest charges resulting from lower deferrals related to infrastructure investments associated with the PISA and RESRAM, both at Ameren Missouri (3 cents and 6 cents per share, respectively);

•increased base rate revenues at Ameren Illinois Natural Gas effective November 28, 2023, pursuant to the November 2023 ICC natural gas rate order, partially offset by increased depreciation and amortization expenses included in base rates (4 cents per share for the six months ended June 30, 2024); and

•a change in rate design at Ameren Illinois Natural Gas pursuant to the November 2023 ICC natural gas rate order that concentrates more revenues in the winter heating season due to an increase in volumetric rates, which increased earnings for the three months ended March 31, 2024, but is not expected to materially impact full year results (2 cents per share for the six months ended June 30, 2024).

Earnings per diluted share were unfavorably affected in the three and six months ended June 30, 2024, compared to the year-ago periods (except where a specific period is referenced), by:

•increased financing costs at Ameren Missouri and Ameren (parent), primarily due to higher long-term debt balances and interest rates (4 cents and 7 cents per share, respectively);

•increased other operations and maintenance expenses not subject to formula rates, riders, or trackers, primarily at Ameren Missouri, excluding a charge related to an increase in the estimated minimum cost of additional mitigation relief discussed below, largely due to the absence in 2024 of the recognition of regulatory assets for previously expensed costs approved for recovery pursuant to the June 2023 MoPSC rate order (3 cents and 6 cents per share, respectively);

•a charge recorded by Ameren Missouri, included in other operation and maintenance expenses, related to an increase in the estimated minimum cost of additional mitigation relief associated with NSR and Clean Air Act litigation applicable to the Rush Island Energy Center, see Note 9 - Commitments and Contingencies under Part 1, Item 1, of this report for more information (4 cents per share for the six months ended June 30, 2024);

•lower revenue at Ameren Illinois Electric Distribution due to a lower recognized ROE under the MYRP (2 cents and 4 cents per share, respectively);

•increased weighted-average basic common shares outstanding resulting from issuances of common shares as detailed in Note 4 – Long-term Debt and Equity Financings under Part I, Item 1, of this report, and Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of the Form 10-K (1 cent and 3 cents per share, respectively);

•increased income tax expense not subject to formula rates or riders, primarily due to a decrease in income tax benefits at Ameren (parent) related to stock-based compensation (2 cents per share for the six months ended June 30, 2024); and

•increased taxes other than income taxes, primarily at Ameren Missouri, largely resulting from the absence in 2024 of employee retention tax credits received under the Coronavirus Aid, Relief, and Economic Security Act (1 cent per share for the six months ended June 30, 2024).

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The cents per share variances above are presented based on the weighted-average basic common shares outstanding in the three and six months ended June 30, 2023, and do not reflect the impact of dilution on earnings per share, unless otherwise noted. The amounts above other than variances related to income taxes have been presented net of income taxes using Ameren’s 2024 blended federal and state statutory tax rate of 26%. For additional details regarding the Ameren Companies’ results of operations, including explanations of Operating Revenues for both Electric Revenues and Natural Gas Revenues; Fuel and Purchased Power Expenses; Other Operations and Maintenance Expenses; Depreciation and Amortization Expenses; Taxes Other Than Income Taxes; Other Income, Net; Interest Charges; and Income Taxes, see the major headings below.

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Below is Ameren’s table of income statement components by segment for the three and six months ended June 30, 2024 and 2023:

	Ameren Missouri		Ameren Illinois Electric Distribution		Ameren Illinois Natural Gas		Ameren Transmission		Other / Intersegment Eliminations		Ameren
Three Months 2024:
Electric revenues	$	864	$	509	$	—	$	191	$	(43)	$	1,521
Natural gas revenues	24		—		148		—		—		172
Fuel and purchased power	(189)		(168)		—		—		30		(327)
Natural gas purchased for resale	(9)		—		(24)		—		—		(33)
Other operations and maintenance expenses	(247)		(153)		(59)		(16)		10		(465)
Depreciation and amortization expenses	(208)		(93)		(33)		(40)		(2)		(376)
Taxes other than income taxes	(91)		(19)		(15)		(2)		(4)		(131)
Operating income (loss)	144		76		17		133		(9)		361
Other income, net	49		27		7		4		16		103
Interest charges	(63)		(26)		(15)		(29)		(32)		(165)
Income (taxes) benefit	(1)		(15)		(3)		(29)		9		(39)
Net income (loss)	129		62		6		79		(16)		260
Noncontrolling interests – preferred stock dividends	(1)		(1)		—		—		—		(2)
Net income (loss) attributable to Ameren common shareholders	$	128	$	61	$	6	$	79	$	(16)	$	258
Three Months 2023:
Electric revenues	$	918	$	540	$	—	$	161	$	(34)	$	1,585
Natural gas revenues	23		—		152		—		—		175
Fuel and purchased power	(289)		(218)		—		—		27		(480)
Natural gas purchased for resale	(9)		—		(33)		—		—		(42)
Other operations and maintenance expenses	(237)		(133)		(58)		(13)		(9)		(450)
Depreciation and amortization expenses	(186)		(87)		(27)		(34)		(1)		(335)
Taxes other than income taxes	(88)		(18)		(13)		(2)		(3)		(124)
Operating income (loss)	132		84		21		112		(20)		329
Other income, net	22		26		8		8		18		82
Interest charges	(52)		(22)		(13)		(23)		(24)		(134)
Income (taxes) benefit	1		(21)		(5)		(25)		12		(38)
Net income (loss)	103		67		11		72		(14)		239
Noncontrolling interests – preferred stock dividends	(1)		(1)		—		—		—		(2)
Net income (loss) attributable to Ameren common shareholders	$	102	$	66	$	11	$	72	$	(14)	$	237

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	Ameren Missouri		Ameren Illinois Electric Distribution		Ameren Illinois Natural Gas		Ameren Transmission		Other / Intersegment Eliminations		Ameren
Six Months 2024:
Electric revenues	$	1,578	$	1,015	$	—	$	376	$	(84)	$	2,885
Natural gas revenues	85		—		539		—		—		624
Fuel and purchased power	(355)		(360)		—		—		60		(655)
Natural gas purchased for resale	(37)		—		(147)		—		—		(184)
Other operations and maintenance expenses	(501)		(289)		(117)		(35)		7		(935)
Depreciation and amortization expenses	(403)		(186)		(66)		(79)		(3)		(737)
Taxes other than income taxes	(178)		(36)		(41)		(4)		(7)		(266)
Operating income (loss)	189		144		168		258		(27)		732
Other income, net	93		49		14		6		30		192
Interest charges	(125)		(48)		(30)		(58)		(58)		(319)
Income (taxes) benefit	(2)		(27)		(40)		(55)		41		(83)
Net income (loss)	155		118		112		151		(14)		522
Noncontrolling interests – preferred stock dividends	(2)		(1)		—		—		—		(3)
Net income (loss) attributable to Ameren common shareholders	$	153	$	117	$	112	$	151	$	(14)	$	519
Six Months 2023:
Electric revenues	$	1,759	$	1,164	$	—	$	324	$	(72)	$	3,175
Natural gas revenues	105		—		543		—		(1)		647
Fuel and purchased power	(610)		(533)		—		—		55		(1,088)
Natural gas purchased for resale	(56)		—		(194)		—		—		(250)
Other operations and maintenance expenses	(476)		(262)		(117)		(29)		(14)		(898)
Depreciation and amortization expenses	(362)		(171)		(53)		(67)		(2)		(655)
Taxes other than income taxes	(168)		(36)		(36)		(4)		(7)		(251)
Operating income (loss)	192		162		143		224		(41)		680
Other income, net	41		50		16		14		39		160
Interest charges	(103)		(43)		(26)		(45)		(44)		(261)
Income (taxes) benefit	2		(41)		(35)		(50)		49		(75)
Net income	132		128		98		143		3		504
Noncontrolling interests – preferred stock dividends	(2)		(1)		—		—		—		(3)
Net income attributable to Ameren common shareholders	$	130	$	127	$	98	$	143	$	3	$	501

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Below is Ameren Illinois’ table of income statement components by segment for the three and six months ended June 30, 2024 and 2023:

	Ameren Illinois Electric Distribution		Ameren Illinois  Natural Gas		Ameren Illinois Transmission		Other / Intersegment Eliminations		Ameren Illinois
Three Months 2024:
Electric revenues	$	509	$	—	$	136	$	(27)	$	618
Natural gas revenues	—		148		—		—		148
Purchased power	(168)		—		—		27		(141)
Natural gas purchased for resale	—		(24)		—		—		(24)
Other operations and maintenance expenses	(153)		(59)		(12)		—		(224)
Depreciation and amortization expenses	(93)		(33)		(28)		—		(154)
Taxes other than income taxes	(19)		(15)		(1)		—		(35)
Operating income	76		17		95		—		188
Other income, net	27		7		3		—		37
Interest charges	(26)		(15)		(19)		—		(60)
Income taxes	(15)		(3)		(22)		—		(40)
Net income	62		6		57		—		125
Preferred stock dividends	(1)		—		—		—		(1)
Net income attributable to common shareholder	$	61	$	6	$	57	$	—	$	124
Three Months 2023:
Electric revenues	540		$	—	$	113	$	(26)	627
Natural gas revenues	—		152		—		—		152
Purchased power	(218)		—		—		26		(192)
Natural gas purchased for resale	—		(33)		—		—		(33)
Other operations and maintenance expenses	(133)		(58)		(10)		—		(201)
Depreciation and amortization expenses	(87)		(27)		(24)		—		(138)
Taxes other than income taxes	(18)		(13)		(1)		—		(32)
Operating income	84		21		78		—		183
Other income, net	26		8		7		—		41
Interest charges	(22)		(13)		(15)		—		(50)
Income taxes	(21)		(5)		(18)		—		(44)
Net income	67		11		52		—		130
Preferred stock dividends	(1)		—		—		—		(1)
Net income attributable to common shareholder	$	66	$	11	$	52	$	—	$	129
Six Months 2024:
Electric revenues	$	1,015	$	—	$	267	$	(55)	$	1,227
Natural gas revenues	—		539		—		—		539
Purchased power	(360)		—		—		55		(305)
Natural gas purchased for resale	—		(147)		—		—		(147)
Other operations and maintenance expenses	(289)		(117)		(28)		—		(434)
Depreciation and amortization expenses	(186)		(66)		(55)		—		(307)
Taxes other than income taxes	(36)		(41)		(2)		—		(79)
Operating income	144		168		182		—		494
Other income, net	49		14		5		—		68
Interest charges	(48)		(30)		(37)		—		(115)
Income taxes	(27)		(40)		(40)		—		(107)
Net income	118		112		110		—		340
Preferred stock dividends	(1)		—		—		—		(1)
Net income attributable to common shareholder	$	117	$	112	$	110	$	—	$	339

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	Ameren Illinois Electric Distribution		Ameren Illinois  Natural Gas		Ameren Illinois Transmission		Other / Intersegment Eliminations		Ameren Illinois
Six Months 2023:
Electric revenues	$	1,164	$	—	$	227	$	(54)	$	1,337
Natural gas revenues	—		543		—		—		543
Purchased power	(533)		—		—		54		(479)
Natural gas purchased for resale	—		(194)		—		—		(194)
Other operations and maintenance expenses	(262)		(117)		(24)		—		(403)
Depreciation and amortization expenses	(171)		(53)		(47)		—		(271)
Taxes other than income taxes	(36)		(36)		(2)		—		(74)
Operating income	162		143		154		—		459
Other income, net	50		16		12		—		78
Interest charges	(43)		(26)		(28)		—		(97)
Income taxes	(41)		(35)		(36)		—		(112)
Net income	128		98		102		—		328
Preferred stock dividends	(1)		—		—		—		(1)
Net income attributable to common shareholder	$	127	$	98	$	102	$	—	$	327

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Operating Revenues

The following table presents the increases (decreases) by Ameren segment for electric and natural gas revenues for the three and six months ended June 30, 2024, compared with the year-ago periods:

Three Months	Ameren Missouri		Ameren Illinois Electric Distribution		Ameren Illinois Natural Gas		Ameren Transmission(a)		Other /Intersegment Eliminations		Ameren
Electric revenue change:
Base rates (estimate)(b)	$	31	$	8	$	—	$	26	$	—	$	65
Effect of weather (estimate)(c)	27		—		—		—		—		27
Sales volumes and changes in customer usage patterns (excluding the estimated effects of weather and MEEIA)	(3)		—		—		—		—		(3)
Off-system sales, capacity, and FAC revenues, net	(96)		—		—		—		—		(96)
Ameren Illinois energy-efficiency program investment revenues	—		7		—		—		—		7
Electric deferred income tax adjustment(d)	—		(4)		—		—		—		(4)
Other	—		(1)		—		4		(6)		(3)
Cost recovery mechanisms – offset in fuel and purchased power(e)	(21)		(50)		—		—		(3)		(74)
Other cost recovery mechanisms(f)	8		9		—		—		—		17
Total electric revenue change	$	(54)	$	(31)	$	—	$	30	$	(9)	$	(64)
Natural gas revenue change:
Base rates (estimate)	$	—	$	—	$	11	$	—	$	—	$	11
Change in rate design (estimate)	—		—		(5)		—		—		(5)
Cost recovery mechanisms – offset in natural gas purchased for resale(e)	1		—		(9)		—		—		(8)
Other cost recovery mechanisms(f)	—		—		(1)		—		—		(1)
Total natural gas revenue change	$	1	$	—	$	(4)	$	—	$	—	$	(3)
Six Months
Electric revenue change:
Base rates (estimate)(b)	$	60	$	16	$	—	$	45	$	—	$	121
Effect of weather (estimate)(c)	21		—		—		—		—		21
Sales volumes and changes in customer usage patterns (excluding the estimated effects of weather and MEEIA)	11		—		—		—		—		11
Off-system sales, capacity, and FAC revenues, net	(247)		—		—		—		—		(247)
Ameren Illinois energy-efficiency program investment revenues	—		11		—		—		—		11
Electric deferred income tax adjustment(d)	—		(9)		—		—		—		(9)
Other	(1)		(3)		—		7		(7)		(4)
Cost recovery mechanisms – offset in fuel and purchased power(e)	(38)		(173)		—		—		(5)		(216)
Other cost recovery mechanisms(f)	13		9		—		—		—		22
Total electric revenue change	$	(181)	$	(149)	$	—	$	52	$	(12)	$	(290)
Natural gas revenue change:
Base rates (estimate)	$	—	$	—	$	35	$	—	$	—	$	35
Change in rate design (estimate)	—		—		6		—		—		6
Effect of weather (estimate)(c)	1		—		—		—		—		1
Other	—		—		3		—		1		4
Cost recovery mechanisms – offset in natural gas purchased for resale(e)	(20)		—		(47)		—		—		(67)
Other cost recovery mechanisms(f)	(1)		—		(1)		—		—		(2)
Total natural gas revenue change	$	(20)	$	—	$	(4)	$	—	$	1	$	(23)

(a)Includes an increase in transmission revenues of $23 million and $40 million at Ameren Illinois for the three and six months ended June 30, 2024, respectively, compared with the year-ago periods.

(b)For Ameren Illinois Electric Distribution and Ameren Transmission, base rates include increases or decreases in operating revenues related to the revenue requirement reconciliation adjustment under the MYRP and formula rates, respectively. For Ameren Missouri, base rates exclude an increase for the recovery of lost electric revenue, less the associated fuel and purchased power expenses, resulting from the MEEIA customer energy-efficiency programs and a decrease in base rates for RESRAM. These changes in Ameren Missouri base rates are included in the “Sales volumes and changes in customer usage patterns (excluding the estimated effects of weather and MEEIA)” and “Cost recovery mechanisms - offset in fuel and purchased power” line items, respectively.

(c)Represents the estimated variation resulting primarily from changes in cooling and heating degree-days on electric and natural gas demand compared with the year-ago periods; this variation is based on temperature readings from National Oceanic and Atmospheric Administration weather stations at local airports in our service territories.

(d)The electric deferred income tax adjustment relates to the remaining balance of certain excess deferred income taxes that will be amortized through 2025. Offsetting expense increases or decreases are reflected within the "Income Taxes" section of the statement of income. This item has no overall impact on earnings.

(e)Electric and natural gas revenue changes are offset by corresponding changes in “Fuel and purchased power” and “Natural gas purchased for resale” on the statement of income. Activity in Other/Intersegment Eliminations represents the elimination of related-party transactions between Ameren Missouri, Ameren Illinois, and ATXI, as well as Ameren Transmission revenue from transmission services provided to Ameren Illinois Electric Distribution. See Note 8 – Related-party Transactions and Note 14 – Segment Information under Part I, Item 1, of this report for additional information on intersegment eliminations. These items have no overall impact on earnings.

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(f)Offsetting expense increases or decreases are reflected in “Other operations and maintenance,” “Depreciation and amortization,” or in “Taxes other than income taxes,” within the “Operating Expenses” section of the statement of income. These items have no overall impact on earnings.

Electric Revenues

Ameren

Ameren’s electric revenues decreased $64 million, or 4%, and $290 million, or 9%, for the three and six months ended June 30, 2024, respectively, compared with the year-ago periods, primarily due to decreased revenues at Ameren Missouri and Ameren Illinois Electric Distribution, partially offset by increased revenues at Ameren Transmission, as discussed below.

Ameren Transmission

Ameren Transmission’s electric revenues increased $30 million, or 19%, and $52 million, or 16%, for the three and six months ended June 30, 2024, respectively, compared with the year-ago periods. Revenues were favorably affected by higher recoverable expenses

(+$15 million and +$25 million, respectively), increased capital investment (+$11 million and +$20 million, respectively), as evidenced by a 14% increase in rate base used to calculate the revenue requirement, and increased facility rental revenues (+$4 million and +$7 million, respectively) related to ATXI’s transmission operations control center, which was placed in service in December 2023. ATXI provides affiliates with access to this facility. Rental revenues associated with this facility are affiliate transactions and eliminated in consolidation for Ameren’s consolidated financial statements. See Note 8 – Related-party Transactions under Part I, Item 1, of this report for additional information.

Ameren Missouri

Ameren Missouri’s electric revenues decreased $54 million, or 6%, and $181 million, or 10%, for the three and six months ended June 30, 2024, respectively, compared with the year-ago periods.

The following items had an unfavorable effect on Ameren Missouri’s electric revenues for the three and six months ended June 30, 2024, compared with the year-ago periods (except where a specific period is referenced):

•“Off-system sales, capacity and FAC revenues, net” decreased $96 million and $247 million, respectively, primarily due to lower capacity prices, (-$98 million and -$254 million, respectively), which were set by annual MISO auctions. Ameren Missouri’s 5% exposure to net energy cost variances under the FAC is included within “Off-system sales, capacity, and FAC revenues, net” and “Energy costs (excluding the estimated effect of weather)” in fuel and purchased power.

•Revenues associated with “Cost recovery mechanisms – offset in fuel and purchased power” decreased $21 million and $38 million, respectively, due to decreased revenue related to the amortization of costs previously deferred under the FAC that were reflected in customer rates. The changes to “Cost recovery mechanisms - offset in fuel and purchased power” are fully offset by “Cost recovery mechanisms - offset in electric revenue” in fuel and purchased power.

•Excluding the estimated effects of weather and the MEEIA customer energy-efficiency programs, electric revenues decreased an estimated $3 million for the three months ended June 30, 2024, due to lower realized prices because of changes in customer usage patterns and economic development discounts, partially offset by an increase in retail sales volumes.

The following items had a favorable effect on Ameren Missouri’s electric revenues for the three and six months ended June 30, 2024, compared with the year-ago periods (except where a specific period is referenced):

•Higher electric base rates, resulting from the June 2023 MoPSC electric rate order effective July 9, 2023, increased revenues an estimated $31 million and $60 million, respectively.

•The aggregate effect of weather increased revenues an estimated $27 million and $21 million, respectively. Spring and early summer temperatures were warmer as cooling degree days increased 35%, while winter temperatures were warmer as heating degree days decreased 7%.

•Revenues associated with other cost recovery mechanisms increased $8 million and $13 million, respectively, primarily due to an increase in RESRAM revenues and an increase in excise taxes due to an increase in retail sales revenue.

•Excluding the estimated effects of weather and the MEEIA customer energy-efficiency programs, electric revenues increased an estimated $11 million for the six months ended June 30, 2024, due to an increase in retail sales volumes, which were, in part, favorably affected by an additional day in 2024 as a result of the leap year, partially offset by lower realized prices due to changes in customer usage patterns and economic development discounts.

Ameren Illinois

Ameren Illinois’ electric revenues decreased $9 million, or 1%, and $110 million, or 8%, for the three and six months ended June 30, 2024, respectively, compared with the year-ago periods, driven by decreased revenues at Ameren Illinois Electric Distribution, partially offset by increased revenues at Ameren Illinois Transmission.

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Ameren Illinois Electric Distribution

Ameren Illinois Electric Distribution’s revenues decreased $31 million, or 6%, and $149 million, or 13%, for the three and six months ended June 30, 2024, respectively, compared with the year-ago periods.

The following items had an unfavorable effect on Ameren Illinois Electric Distribution’s revenues for the three and six months ended June 30, 2024, compared with the year-ago periods:

•Revenues associated with “Cost recovery mechanisms – offset in fuel and purchased power” decreased $50 million and $173 million, respectively, due to decreased recovery of purchased power expenses. The decreases in electric revenues are fully offset by decreases in purchased power expenses under cost recovery mechanisms for purchased power, as discussed below.

•Pursuant to an ICC order, revenues decreased $4 million and $9 million, respectively, due to an increase in the amortization rate for certain excess deferred income taxes.

The following items had a favorable effect on Ameren Illinois Electric Distribution’s revenues for the three and six months ended June 30, 2024, compared with the year-ago periods (except where a specific period is referenced):

•Base rates increased revenues by $8 million and $16 million, respectively, due primarily to higher recoverable non-purchased power expenses (+$12 million and +$25 million, respectively) and increased capital investment (+$1 million and +$1 million, respectively), partially offset by a lower recognized ROE (-$5 million and -$10 million, respectively). The MYRP utilizes a fixed ROE approved by the ICC of 8.72%, with adjustments for any performance incentives and penalties, while the IEIMA formula-based ROE was based on the annual average of the monthly yields of the 30-year United States Treasury bonds plus 580 basis points (estimated at 9.64% for the six months ended June 30, 2023).

•Revenues associated with customer energy-efficiency program investments increased $7 million and $11 million, respectively, due to the recovery of program expenses (+$4 million and +$7 million, respectively), an increase in the ROE due to maximum achievement of the annual energy savings goals in 2023 (+$3 million and +$3 million, respectively), and increased investment of $1 million for the six months ended June 30, 2024.

•Other cost recovery mechanisms increased revenues by $9 million in both periods, primarily due to a higher amount of bad debt and consolidated billing costs included in customer rates pursuant to their associated riders, partially offset by lower environmental remediation revenues.

Ameren Illinois Transmission

Ameren Illinois Transmission’s revenues increased $23 million, or 20%, and $40 million, or 18%, for the three and six months ended June 30, 2024, respectively, compared with the year-ago periods. Base rate revenues were favorably affected by higher recoverable expenses (+$14 million and +$25 million, respectively) and increased capital investment (+$9 million and +$15 million, respectively), as evidenced by a 15% increase in rate base used to calculate the revenue requirement.

Natural Gas Revenues

Ameren

Ameren’s natural gas revenues decreased $3 million, or 2%, and $23 million, or 4%, for the three and six months ended June 30, 2024, respectively, compared with the year-ago periods, due to decreased revenues at Ameren Missouri and Ameren Illinois Natural Gas, as discussed below.

Ameren Missouri

Ameren Missouri’s natural gas revenues were comparable for the three months ended June 30, 2024, and decreased $20 million, or 19%, for the six months ended June 30, 2024, respectively, compared with the year-ago periods. Revenues associated with “Cost recovery mechanisms – offset in natural gas purchased for resale” decreased $20 million for the six months ended June 30, 2024, due to lower commodity prices and the absence of amortization of natural gas costs deferred under the PGA related to the extremely cold weather in mid-February 2021. Changes in natural gas revenues under the PGA are fully offset by corresponding changes in natural gas purchased for resale expenses.

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Ameren Illinois Natural Gas

Ameren Illinois Natural Gas’ revenues decreased $4 million, or 3%, and $4 million, or 1%, for the three and six months ended June 30, 2024, respectively, compared with the year-ago periods. “Cost recovery mechanisms – offset in natural gas purchased for resale” decreased revenues $9 million and $47 million, respectively, for the three and six months ended June 30, 2024, due to lower collection of natural gas costs previously deferred under the PGA. The decreases in natural gas revenues under the PGA are fully offset by decreases in natural gas purchased for resale expenses.

The following items had a favorable effect on Ameren Illinois Natural Gas’ revenues for the three and six months ended June 30, 2024, compared with the year-ago periods (except where a specific period is referenced):

•Revenues increased an estimated $11 million and $35 million, respectively, due to higher natural gas base rates as a result of the November 2023 natural gas rate order.

•Revenues increased an estimated $6 million for the six months ended June 30, 2024, due to a change in rate design as a result of the November 2023 natural gas rate order. This change in rate design concentrates more revenues in the winter heating season due to an increase in volumetric rates and a decrease in fixed customer rates. As such, the change is not expected to materially affect annual earnings comparisons.

Ameren Illinois Natural Gas’ revenues decreased an estimated $5 million for the three months ended June 30, 2024, due to a change in rate design as a result of the November 2023 natural gas rate order. As noted above, the change is not expected to materially affect annual earnings comparisons.

Fuel and Purchased Power

The following table presents the increases (decreases) by Ameren segment for fuel and purchased power for the three and six months ended June 30, 2024, compared with the year-ago periods:

Three Months	Ameren Missouri		Ameren Illinois Electric Distribution		Ameren Illinois Natural Gas		Ameren Transmission		Other /Intersegment Eliminations		Ameren
Fuel and purchased power change:
Energy costs (excluding the estimated effect of weather)	$	(95)	$	—	$	—	$	—	$	—	$	(95)
Effect of weather (estimate)(a)	4		—		—		—		—		4
Effect of higher net energy costs included in base rates	10		—		—		—		—		10
Other	2		—		—		—		—		2
Cost recovery mechanisms – offset in electric revenue(b)	(21)		(50)		—		—		(3)		(74)
Total fuel and purchased power change	$	(100)	$	(50)	$	—	$	—	$	(3)	$	(153)
Six Months
Fuel and purchased power change:
Energy costs (excluding the estimated effect of weather)	$	(243)	$	—	$	—	$	—	$	—	$	(243)
Effect of weather (estimate)(a)	3		—		—		—		—		3
Effect of higher net energy costs included in base rates	21		—		—		—		—		21
Other	2		—		—		—		—		2
Cost recovery mechanisms – offset in electric revenue(b)	(38)		(173)		—		—		(5)		(216)
Total fuel and purchased power change	$	(255)	$	(173)	$	—	$	—	$	(5)	$	(433)

(a)Represents the estimated variation resulting primarily from changes in cooling and heating degree-days on electric demand compared with the year-ago periods; this variation is based on temperature readings from the National Oceanic and Atmospheric Administration weather stations at local airports in our service territories.

(b)“Cost recovery mechanisms — offset in electric revenue” changes are offset by corresponding changes in “Cost recovery mechanisms — offset in fuel and purchased power” in electric revenues. Activity in Other/Intersegment Eliminations represents the elimination of related-party transactions between Ameren Missouri, Ameren Illinois, and ATXI, as well as Ameren Transmission revenue from transmission services provided to Ameren Illinois Electric Distribution. See Note 8 – Related-party Transactions and Note 14 – Segment Information under Part I, Item 1, of this report for additional information on intersegment eliminations. These items have no overall impact on earnings.

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Ameren

Ameren Missouri and Ameren Illinois are generally allowed to pass on to customers prudently incurred costs for fuel and purchased power. Ameren’s electric fuel and purchased power expenses decreased $153 million, or 32%, and $433 million, or 40%, for the three and six months ended June 30, 2024, respectively, compared with the year-ago periods, primarily due to decreased fuel and purchased power expenses at Ameren Missouri and Ameren Illinois Electric Distribution, as discussed below.

Ameren Missouri

Ameren Missouri’s fuel and purchased power expenses decreased $100 million, or 35%, and $255 million, or 42%, for the three and six months ended June 30, 2024, respectively, compared with the year-ago periods.

The following items decreased Ameren Missouri’s fuel and purchased power expense for the three and six months ended June 30, 2024, compared with the year-ago periods:

•Energy costs decreased $95 million and $243 million, respectively, due primarily to decreased capacity prices, which were set by annual MISO auctions. Ameren Missouri’s 5% exposure to net energy cost variances under the FAC is included within “Energy costs (excluding the estimated effect of weather)” and “Off-system sales, capacity, and FAC revenues, net” in electric revenues.

•“Cost recovery mechanisms — offset in electric revenue” decreased $21 million and $38 million, respectively, due to decreased amortization of costs previously deferred under the FAC. The changes to “Cost recovery mechanisms - offset in electric revenue” are fully offset by “Cost recovery mechanisms - offset in fuel and purchased power” in electric revenues.

The following items increased Ameren Missouri’s fuel and purchased power expense for the three and six months ended June 30, 2024, compared with the year-ago periods:

•Ameren Missouri’s fuel and purchased power expenses increased $10 million and $21 million, respectively, due to the effect of higher net energy costs included in base rates as a result of the June 2023 MoPSC electric rate order.

•Fuel and purchased power expenses increased an estimated $4 million and $3 million, respectively, due to an increase in electric retail sales as a result of warmer spring and early summer temperatures.

Ameren Illinois Electric Distribution

Ameren Illinois Electric Distribution’s purchased power expenses decreased $50 million, or 23%, and $173 million, or 32%, for the three and six months ended June 30, 2024, respectively, compared with the year-ago periods, primarily due to decreased energy prices

(-$21 million and -$78 million, respectively), which largely reflect the results of IPA procurement events, decreased capacity prices

(-$20 million and -$59 million, respectively), which were set by annual MISO auctions, and lower volumes (-$9 million and -$37 million, respectively) primarily due to residential and small commercial customers switching from Ameren Illinois’ supplied power to alternative retail electric suppliers. The changes to “Cost recovery mechanisms - offset in electric revenue” are fully offset by “Cost recovery mechanisms - offset in fuel and purchased power” in electric revenues.

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Natural Gas Purchased for Resale

The following table presents the increases (decreases) by Ameren segment for natural gas purchased for resale for the three and six months ended June 30, 2024, compared with the year-ago periods:

Three Months	Ameren Missouri		Ameren Illinois Electric Distribution		Ameren Illinois Natural Gas		Ameren Transmission		Other /Intersegment Eliminations		Ameren
Natural gas purchased for resale change:
Effect of weather (estimate)(a)	$	(1)	$	—	$	—	$	—	—		$	(1)
Cost recovery mechanisms – offset in natural gas revenue(b)	1		—		(9)		—		—		(8)
Total natural gas purchased for resale change	$	—	$	—	$	(9)	$	—	$	—	$	(9)
Six Months
Natural gas purchased for resale change:
Effect of weather (estimate)(a)	$	1	$	—	$	—	$	—	$	—	$	1
Cost recovery mechanisms – offset in natural gas revenue(b)	(20)		—		(47)		—		—		(67)
Total natural gas purchased for resale change	$	(19)	$	—	$	(47)	$	—	$	—	$	(66)

(a)Represents the estimated variation resulting primarily from changes in cooling and heating degree-days on natural gas demand compared with the year-ago periods; this variation is based on temperature readings from the National Oceanic and Atmospheric Administration weather stations at local airports in our service territories.

(b)Natural gas purchased for resale changes are offset by corresponding changes in “Natural gas revenues” on the statement of income. These items have no overall impact on earnings.

Ameren

Ameren Missouri and Ameren Illinois are allowed to pass on to customers prudently incurred costs for natural gas purchased for resale. Ameren’s natural gas purchased for resale expenses decreased $9 million, or 21%, and $66 million, or 26%, for the three and six months ended June 30, 2024, respectively, compared with the year-ago periods, due to decreased natural gas purchased for resale expenses at Ameren Illinois Natural Gas and Ameren Missouri, as discussed below.

Ameren Missouri

Ameren Missouri’s natural gas purchased for resale expenses were comparable for the three months ended June 30, 2024, and decreased $19 million, or 34%, for the six months ended June 30, 2024, compared with the year-ago periods. Expenses associated with “Cost recovery mechanisms – offset in natural gas revenue” decreased $20 million for the six months ended June 30, 2024, due to lower commodity prices and the absence of amortization of natural gas costs deferred under the PGA related to the extremely cold weather in mid-February 2021. Changes in natural gas purchased for resale expenses are fully offset by corresponding changes in natural gas revenues under the PGA.

Ameren Illinois Natural Gas

Ameren Illinois Natural Gas’ natural gas purchased for resale expenses decreased $9 million, or 27%, and $47 million, or 24%, for the three and six months ended June 30, 2024, respectively, compared with the year-ago periods, primarily due to lower amortization of natural gas costs that were previously deferred under the PGA and lower natural gas prices. Decreases in natural gas purchased for resale expenses are fully offset by decreases in natural gas revenues under the PGA.

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Other Operations and Maintenance Expenses

	Increase (Decrease) by Segment
	Overall Ameren Increase of $15 Million (QTD YoY)	Overall Ameren Increase of $37 Million (YTD YoY)
Total by Segment(a)

(a)Includes $16 million and $13 million at Ameren Transmission in the three months ended June 30, 2024 and 2023, respectively. Includes other/intersegment eliminations of $(10) million and $9 million in the three months ended June 30, 2024 and 2023, respectively. Also includes other/intersegment eliminations of $(7) million and $14 million in the six months ended June 30, 2024 and 2023, respectively.

Ameren Missouri	Ameren Illinois Natural Gas	Other/Intersegment Eliminations
Ameren Illinois Electric Distribution	Ameren Transmission

Ameren

Other operations and maintenance expenses increased $15 million and $37 million in the three and six months ended June 30, 2024, respectively, compared with the year-ago periods, because of the changes discussed below. In addition to changes by segments discussed below, other operations and maintenance expenses decreased $19 million and $21 million in the three and six months ended June 30, 2024, respectively, for activity not reported as part of a segment, as reflected in “Other/Intersegment Eliminations” above, because of an $8 million gain on the sale of land in both periods; an increase in the elimination of intercompany rent related to ATXI’s operations control center discussed below of $3 million and $5 million, respectively; and an increase in the elimination of the non-service cost component of net periodic benefit income at Ameren Services of $2 million and $5 million, respectively. The non-service cost component of net periodic benefit cost or income at Ameren Services is allocated to the segments and primarily included in the segments’ other operations and maintenance expenses.

Ameren Transmission

Other operations and maintenance expenses increased $3 million and $6 million in the three and six months ended June 30, 2024, respectively, compared with the year-ago periods, primarily because of increased costs related to ATXI’s operations control center, which was placed in service in December 2023. ATXI provides affiliates with access to this facility. The rent expense associated with this facility is an affiliate transaction and eliminated in consolidation for purposes of Ameren’s consolidated financial statements. See Note 8 – Related-party Transactions under Part I, Item 1, of this report for additional information.

Ameren Missouri

Other operations and maintenance expenses increased $10 million and $25 million in the three and six months ended June 30, 2024, respectively, compared with the year-ago periods. The following items increased other operations and maintenance expenses in the three and six months ended June 30, 2024, compared with the year-ago periods (except where a specific period is referenced):

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•A $15 million charge in the six months ended June 30, 2024, related to an increase in the estimated minimum cost of additional mitigation relief associated with NSR and Clean Air Act litigation related to the Rush Island Energy Center, see Note 9 - Commitments and Contingencies under Part 1, Item 1, of this report for more information.

•The absence in 2024 of the recognition of regulatory assets for previously expensed costs approved for recovery pursuant to the June 2023 MoPSC rate order increased expenses $15 million in both periods.

•Individually insignificant increases of $6 million and $9 million in various other operations and maintenance expenses, including other labor, cloud computing costs, and amortization of regulatory assets associated with previously expensed costs approved for recovery pursuant to the June 2023 MoPSC rate order.

•Renewable development costs increased $4 million and $6 million, respectively, primarily due to the absence in 2024 of the MoPSC order approving CCNs for the Boomtown and Huck Finn solar projects in the first half of 2023 that led to increased capitalization of renewable development costs pursuant to anticipated recovery from customers.

•Legal and administrative expenses increased by $3 million and $5 million, respectively, primarily related to environmental matters.

The above increases in the three and six months ended June 30, 2024, compared with the year-ago periods, were partially offset by the following items:

•Pension and benefit costs decreased $11 million and $23 million, primarily because of a lower base level of expenses, subject to a tracker, included in customer rates pursuant to the June 2023 MoPSC electric rate order. See Note 11 - Retirement Benefits under Part 1, Item 1 of this report for more information.

•Energy center costs decreased $4 million and $9 million, primarily because of lower amortization of Callaway Energy Center refueling and maintenance costs resulting from the fall 2023 outage, compared to the spring 2022 outage.

Ameren Illinois

Other operations and maintenance expenses increased $23 million and $31 million in the three and six months ended June 30, 2024, respectively, compared with the year-ago periods, as discussed below. Other operations and maintenance expenses were comparable at Ameren Illinois Transmission and Ameren Illinois Natural Gas between periods.

Ameren Illinois Electric Distribution

Other operations and maintenance increased $20 million and $27 million, in the three and six months ended June 30, 2024, respectively, compared with the year-ago periods primarily due to the following items:

•Bad debt costs increased $10 million and $16 million, respectively, primarily because of a higher base level of expenses included in customer rates pursuant to the associated rider.

•Individually insignificant increases of $3 million and $7 million in various other operations and maintenance expenses, including labor expenses, injuries and damages, and cloud computing costs.

•Increased costs associated with customer energy-efficiency investments under formula ratemaking of $3 million and $6 million, respectively, primarily due to amortization of regulatory assets.

•Amortization of previous deferrals associated with bad debt costs on purchased receivables increased $5 million in both periods, primarily because of a higher base level of expenses included in customer rates pursuant to the associated rider.

•Increased legal and digital expenses of $4 million in both periods.

•Increased costs of $1 million and $2 million, respectively, associated with electrification programs.

The above increases in the three and six months ended June 30, 2024, compared with the year-ago periods, were partially offset by the following items:

•Distribution expenditures decreased $6 million and $8 million, respectively, primarily because of the timing of maintenance activity.

•Reduction in environmental remediation rider costs of $4 million and $8 million, respectively.

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Depreciation and Amortization Expenses

	Increase by Segment
	Overall Ameren Increase of $41 Million (QTD YoY)	Overall Ameren Increase of $82 Million (YTD YoY)
Total by Segment(a)

(a)Includes other/intersegment eliminations of $2 million and $1 million in the three months ended June 30, 2024 and 2023, respectively. Also includes other/intersegment eliminations of $3 million and $2 million in the six months ended June 30, 2024 and 2023, respectively.    

Ameren Missouri	Ameren Illinois Natural Gas	Other/Intersegment Eliminations
Ameren Illinois Electric Distribution	Ameren Transmission

Depreciation and amortization expenses increased $41 million, $22 million, and $16 million in the three months ended June 30, 2024, and $82 million, $41 million, and $36 million, in the six months ended June 30, 2024, compared with the year-ago periods, at Ameren, Ameren Missouri, and Ameren Illinois, respectively, primarily because of additional property, plant, and equipment investments across their respective segments. Ameren’s and Ameren Missouri’s depreciation and amortization expenses for the three and six months ended June 30, 2024, compared with the year-ago periods, were affected by the following, which include the effect of the additional investments at Ameren Missouri:

•Increased depreciation and amortization of $20 million and $40 million, respectively, due to the inclusion in base rates of amounts previously deferred under the PISA and RESRAM effective July 9, 2023, pursuant to the June 2023 MoPSC electric rate order.

•The lower net under-recovery of RESRAM eligible expenses and increased amortization of prior deferrals increased depreciation and amortization expenses by $11 million and $18 million, respectively.

•Depreciation and amortization rate changes pursuant to the electric rate orders noted above, which increased depreciation and amortization expenses by $2 million and $4 million, respectively.

•Depreciation and amortization expenses reflected a deferral to a regulatory asset of depreciation associated with investments in eligible property, plant, and equipment not yet included in base rates, pursuant to PISA and RESRAM. Base rates were updated to include the eligible property, plant, and equipment in-service through December 31, 2022, when new customer rates became effective on July 9, 2023, pursuant to the June 2023 MoPSC electric rate order. The effect of rebasing PISA and RESRAM, partially offset by increased amortization of prior PISA deferrals, decreased depreciation and amortization by $7 million and $16 million, respectively.

•The higher net deferral pursuant to a tracker related to certain excess deferred income taxes, which decreased depreciation and amortization expenses by $3 million and $5 million, respectively.

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Taxes Other Than Income Taxes

	Increase by Segment
	Overall Ameren Increase of $7 Million (QTD YoY)	Overall Ameren Increase of $15 Million (YTD YoY)
Total by Segment(a)

(a)Includes $2 million, $2 million, $4 million, and $4 million at Ameren Transmission in the three months ended June 30, 2024 and 2023, and in the six months ended June 30, 2024 and 2023, respectively. Also includes other/intersegment eliminations of $4 million, $3 million, $7 million, and $7 million in the three months ended June 30, 2024 and 2023, and in the six months ended June 30, 2024 and 2023, respectively.

Ameren Missouri	Ameren Illinois Natural Gas	Other/Intersegment Eliminations
Ameren Illinois Electric Distribution	Ameren Transmission

Taxes other than income taxes increased $7 million in the three months ended June 30, 2024, compared with the year-ago period, primarily because an increase of $3 million in gross receipts taxes at Ameren Missouri, primarily due to increased retail electric sales, and an increase of $2 million at Ameren Illinois Natural Gas due to an increase in excise taxes resulting from higher invested capital taxes.

Taxes other than income taxes increased $15 million in the six months ended June 30, 2024, compared with the year-ago period, primarily because of an increase of $5 million and $2 million at Ameren Missouri and Ameren Illinois Electric Distribution, respectively, because of the absence in 2024 of employee retention tax credits received under the Coronavirus Aid, Relief, and Economic Security Act; an increase of $4 million at Ameren Illinois Natural Gas due to an increase in excise taxes resulting from higher invested capital taxes; and an increase of $3 million in gross receipts taxes at Ameren Missouri, primarily due to increased retail electric sales.

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Other Income, Net

	Increase (Decrease) by Segment
	Overall Ameren Increase of $21 Million (QTD YoY)	Overall Ameren Increase of $32 Million (YTD YoY)
Total by Segment(a)

(a)Includes $4 million and $8 million at Ameren Transmission in the three months ended June 30, 2024 and 2023, respectively.

Ameren Missouri	Ameren Illinois Natural Gas	Other/Intersegment Eliminations
Ameren Illinois Electric Distribution	Ameren Transmission

See Note 5 – Other Income, Net, under Part I, Item 1, of this report for additional information. See Note 11 – Retirement Benefits under Part I, Item 1, of this report for more information on the non-service cost components of net periodic benefit income.

Ameren

Other income, net, increased $21 million and $32 million in the three and six months ended June 30, 2024, respectively, compared with the year-ago periods. In addition to changes discussed below, other income, net, decreased $3 million and $7 million, respectively, because of increases in the non-service cost component of net periodic benefit income.

Ameren Transmission

Other income, net, decreased $4 million and $8 million in the three and six months ended June 30, 2024, respectively, compared with the year-ago periods, primarily because of a decrease of $4 million and $8 million, respectively, due to lower allowance for equity funds used during construction, primarily related to lower average construction work in progress balances and an increased level of short-term borrowings included in the calculation.

Ameren Missouri

Other income, net, increased $27 million and $52 million in the three and six months ended June 30, 2024, respectively, compared with the year-ago periods, primarily because of an increase of $21 million and $41 million, respectively, in the non-service cost component of net periodic benefit income, primarily because of changes in the base level of pension and postretirement costs pursuant to the June 2023 MoPSC electric rate order. Other income, net, also increased $6 million and $11 million, respectively, because of a higher allowance for equity funds used during construction resulting from higher average construction work in progress balances.

Ameren Illinois

Other income, net, decreased $4 million and $10 million in the three and six months ended June 30, 2024, respectively, compared with the year-ago period, primarily because of a decrease of $4 million and $7 million, respectively, in the non-service cost component of net

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periodic benefit income at Ameren Illinois Electric Distribution and Ameren Illinois Transmission. Other income, net, decreased $3 million and $7 million, respectively, due to lower allowance for equity funds used during construction, largely at Ameren Illinois Transmission, primarily because of lower average construction work in progress balances and an increased level of short-term borrowings included in the calculation. These decreases were partially offset by increased interest income on regulatory asset balances of $4 million and $5 million, respectively, at Ameren Illinois Electric Distribution.

Interest Charges

	Increase by Segment
	Overall Ameren Increase of $31 Million (QTD YoY)	Overall Ameren Increase of $58 Million (YTD YoY)
Total by Segment

Ameren Missouri	Ameren Illinois Natural Gas	Other/Intersegment Eliminations
Ameren Illinois Electric Distribution	Ameren Transmission

See Note 3 – Short-term Debt and Liquidity under Part I, Item 1, of this report and the Long-term Debt and Equity section below for additional information on short-term borrowings and long-term debt, respectively, discussed below.

Ameren

Interest charges increased $31 million and $58 million in the three and six months ended June 30, 2024, respectively, compared with the year-ago periods. In addition to changes by segments discussed below, interest charges increased $8 million and $14 million, respectively at Ameren (parent) primarily because of issuances of long-term debt in November and December of 2023, which collectively increased interest charges by $17 million and $35 million, respectively. The net proceeds from these issuances were used to repay short-term borrowings, which decreased short-term interest expense by $8 million and $21 million, respectively, compared with the year-ago periods.

Ameren Transmission

Interest charges increased $6 million and $13 million in the three and six months ended June 30, 2024, respectively, compared with the year-ago periods, because of an increase of $1 million and $4 million, respectively, due to increased levels of intercompany borrowings and an increase of $3 million and $6 million, respectively, due to higher long-term debt balances. Additionally, interest charges increased because of a higher interest rate on an increased level of short-term borrowings in both periods.

Ameren Missouri

Interest charges increased $11 million and $22 million in the three and six months ended June 30, 2024, respectively, compared with the year-ago periods, because of the following items:

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•Issuances of long-term debt in March 2023, January 2024, and April 2024, which collectively increased interest charges by $11 million and $20 million, respectively.

•Interest charges reflected a deferral to a regulatory asset of interest associated with investments in eligible property, plant, and equipment not yet included in base rates, pursuant to PISA and RESRAM. Base rates were updated to include the eligible property, plant, and equipment in-service through December 31, 2022, when new customer rates became effective on July 9, 2023, pursuant to the June 2023 MoPSC electric rate order. This update to base rates resulted in a lower deferral of interest in 2024 pursuant to PISA and RESRAM that increased interest charges by $5 million and $9 million, respectively.

The above increases were partially offset by a decrease of $2 million and $6 million, respectively, related to lower levels of short-term borrowings.

Ameren Illinois

Interest charges increased $10 million and $18 million in the three and six months ended June 30, 2024, respectively, compared with the year-ago periods, primarily because of the following:

Ameren Illinois Transmission

Interest charges increased by $4 million and $9 million, respectively, primarily because of an issuance of long-term debt in May 2023 which increased interest charges by $2 million and $4 million, respectively. Additionally, a higher interest rate on an increased level of short-term borrowings increased interest charges by $2 million and $3 million, respectively.

Ameren Illinois Electric Distribution

Interest charges increased by $4 million and $5 million, respectively, primarily because of an issuance of long-term debt in May 2023 which increased interest charges by $2 million and $4 million, respectively. Additionally, a higher interest rate on an increased level of short-term borrowings increased interest charges by $2 million in both periods.

Ameren Illinois Natural Gas

Interest charges increased by $2 million and $4 million, respectively, primarily because of an issuance of long-term debt in May 2023 which increased interest charges by $1 million and $3 million, respectively. Additionally, a higher interest rate on an increased level of short-term borrowings increased interest charges by $1 million and $2 million, respectively.

Income Taxes

The following table presents effective income tax rates for the three and six months ended June 30, 2024 and 2023:

	Three Months(a)				Six Months(a)
	2024		2023		2024		2023
Ameren	13	%	14	%	14	%	13	%
Ameren Missouri	1	%	(1)	%	2	%	(1)	%
Ameren Illinois	24	%	25	%	24	%	25	%
Ameren Illinois Electric Distribution	20	%	25	%	18	%	25	%
Ameren Illinois Natural Gas	35	%	27	%	27	%	26	%
Ameren Illinois Transmission	27	%	26	%	26	%	26	%
Ameren Transmission	27	%	26	%	27	%	26	%

(a)Estimate of the annual effective income tax rate adjusted to reflect the tax effect of items discrete to the three and six months ended June 30, 2024 and 2023.

See Note 12 – Income Taxes under Part I, Item 1, of this report for a reconciliation of the federal statutory corporate income tax rate to the effective income tax rate for the Ameren Companies.

The effective tax rate was higher at Ameren Illinois Natural Gas in the three months ended June 30, 2024, compared with the year-ago period, primarily because of the timing of pre-tax income and lower tax benefits related to the allowance for funds used during construction. The effective tax rate was lower at Ameren Illinois Electric Distribution in the three and six months ended June 30, 2024, compared with the year-ago periods, primarily because of an increase in excess deferred tax amortization pursuant to an ICC order, which was offset by a corresponding decrease in revenues.

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LIQUIDITY AND CAPITAL RESOURCES

Collections from our tariff-based revenues are our principal source of cash provided by operating activities. A diversified retail customer mix, primarily consisting of rate-regulated residential, commercial, and industrial customers, provides us with a reasonably predictable source of cash. In addition to using cash provided by operating activities, we use available cash, drawings under committed credit agreements, commercial paper issuances, and/or, in the case of Ameren Missouri and Ameren Illinois, short-term affiliate borrowings to support normal operations and temporary capital requirements. We may reduce our short-term borrowings with cash provided by operations or, at our discretion, with long-term borrowings, or, in the case of Ameren Missouri and Ameren Illinois, with capital contributions from Ameren (parent). As of June 30, 2024, there have been no material changes other than in the ordinary course of business related to cash requirements arising from the long-term commitments for fuel for generation, purchased power, and natural gas for distribution as described under Liquidity and Capital Resources in Item 7 of the Form 10-K.

We expect to make significant capital expenditures over the next five years, supported by a combination of long-term debt and equity, as we invest in our electric and natural gas utility infrastructure to support overall system reliability, grid modernization, renewable energy target requirements, environmental compliance, and other improvements. For additional information about our long-term debt outstanding, including maturities due within one year, and the applicable interest rates, see Note 5 – Long-term Debt and Equity Financings under Part II, Item 8 of the Form 10-K and Note 4 – Long-term Debt and Equity Financings under Part I, Item 1, of this report. As part of its funding plan for capital expenditures, Ameren is using newly issued shares of common stock to satisfy requirements under the DRPlus and employee benefit plans and expects to continue to do so through at least 2028. Additionally, Ameren has an ATM program under which Ameren may offer and sell from time to time common stock, which includes the ability to enter into forward sales agreements, subject to market conditions and other factors. There were no shares issued under the ATM program during the six months ended June 30, 2024. As of June 30, 2024, Ameren had multiple forward sale agreements that could be settled under the ATM program with various counterparties relating to 2.9 million shares of common stock. Ameren expects to settle approximately $230 million of the forward sale agreements with physical delivery of 2.9 million shares of common stock by December 31, 2024. Including issuances under the DRPlus and employee benefit plans, Ameren plans to issue approximately $300 million of equity in 2024 and approximately $600 million of equity each year from 2025 to 2028. As of June 30, 2024, Ameren had approximately $770 million of common stock available for sale under the ATM program, which takes into account the forward sale agreements in effect as of June 30, 2024. Ameren expects its equity to total capitalization to support solid investment-grade credit ratings. See Long-term Debt and Equity below and Note 4 – Long-term Debt and Equity Financings under Part I, Item 1, of this report for additional information on the ATM program, including the forward sale agreements under the ATM program relating to common stock.

The following table presents net cash provided by (used in) operating, investing, and financing activities for the six months ended June 30, 2024 and 2023:

	Net Cash Provided By Operating Activities								Net Cash Used In Investing Activities						Net Cash Provided By Financing Activities
	2024			2023			Variance		2024		2023		Variance		2024		2023		Variance
Ameren	$	1,049	(a)	$	1,111	(a)	$	(62)	$	(1,932)	$	(1,889)	$	(43)	$	912	$	808	$	104
Ameren Missouri	407			443			(36)		(1,155)		(980)		(175)		749		532		217
Ameren Illinois	691		(a)	637		(a)	54		(742)		(846)		104		90		247		(157)

(a)Both Ameren and Ameren Illinois’ cash provided by operating activities included cash outflows of $53 million and $56 million for the FEJA electric energy-efficiency rider and $14 million and $5 million for the customer generation rebate program for the six months ended June 30, 2024 and 2023, respectively.

Cash Flows from Operating Activities

Our cash provided by operating activities is affected by fluctuations of trade accounts receivable, inventories, and accounts and wages payable, among other things, as well as the unique regulatory environment for each of our businesses. Substantially all expenditures related to fuel, purchased power, and natural gas purchased for resale are recovered from customers through rate adjustment mechanisms, which may be adjusted without a traditional regulatory rate review, subject to prudence reviews. Similar regulatory mechanisms exist for certain other operating expenses that can also affect the timing of cash provided by operating activities. The timing of cash payments for costs recoverable under our regulatory mechanisms differs from the recovery period of those costs. Additionally, the seasonality of our electric and natural gas businesses, primarily caused by seasonal customer rates and changes in customer demand due to weather, significantly affects the amount and timing of our cash provided by operating activities.

Ameren

Ameren’s cash provided by operating activities decreased $62 million in the first six months of 2024, compared with the year-ago period. The following items contributed to the decrease:

•A $141 million increase in net collateral posted with counterparties, primarily due to changes in the market prices of power, natural gas, and other fuels.

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•A $34 million increase in the cost of natural gas held in storage, primarily at Ameren Illinois, because of higher volumes, partially offset by lower commodity prices.

•A $27 million increase in interest payments, primarily due to an increase in the average outstanding debt and an increase in interest rates.

•A $25 million decrease resulting from lower customer collections under cost recovery mechanisms at Ameren Missouri, partially offset by increased customer collections resulting primarily from base rate increases effective July 1, 2023, at Ameren Missouri pursuant to the June 2023 electric rate order and base rate increases effective November 28, 2023, at Ameren Illinois pursuant to the November 2023 natural gas rate order and electric transmission rate base growth.

The following items partially offset the decrease in Ameren’s cash from operating activities between periods:

•A $32 million increase due to higher purchases of materials and supplies inventories in the year-ago period to support operations as levels were increased to mitigate against potential supply disruptions.

•A $30 million increase due to higher coal purchases in the year-ago period to bring coal inventories back to targeted levels after transportation delays experienced in 2022.

•A $28 million increase due to the transfer of production tax credits generated by the High Prairie Renewable and Atchison Renewable energy centers to unrelated parties and lower income tax payments primarily due to lower taxable income compared to the year-ago period.

•A $22 million increase due to insurance proceeds received related to workers’ compensation payments made in 2023 at Ameren Illinois.

•An $18 million increase due to workers’ compensation payments made in the year-ago period at Ameren Illinois.

•A $10 million increase due to the timing of payments received from the DOE for reimbursement of spent nuclear fuel storage and related costs.

•A $7 million increase due to the timing of payments for accounts payable.

Ameren Missouri

Ameren Missouri’s cash provided by operating activities decreased $36 million in the first six months of 2024, compared with the year-ago period. The following items contributed to the decrease:

•An $84 million increase in net collateral posted with counterparties, primarily due to changes in the market prices of power, natural gas, and other fuels.

•A $58 million decrease resulting from lower customer collections under cost recovery mechanisms, partially offset by increased customer collections resulting primarily from base rate increases effective July 1, 2023, pursuant to the June 2023 electric rate order.

•A $9 million increase in interest payments, primarily due to an increase in the average outstanding debt and an increase in interest rates.

The following items partially offset the decrease in Ameren Missouri’s cash from operating activities between periods:

•A $33 million increase due to higher purchases of materials and supplies inventories in the year-ago period to support operations, as levels were increased to mitigate against potential supply disruptions.

•A $32 million increase due to the transfer of production tax credits generated by the High Prairie Renewable and Atchison Renewable energy centers to unrelated parties, as well as an income tax refund from Ameren (parent), pursuant to the tax allocation agreement, primarily due to lower taxable income compared to the year-ago period.

•A $30 million increase due to higher coal purchases in the year-ago period to bring coal inventories back to targeted levels after transportation delays experienced in 2022.

•A $10 million increase due to the timing of payments received from the DOE for reimbursement of spent nuclear fuel storage and related costs.

Ameren Illinois

Ameren Illinois’ cash provided by operating activities increased $54 million in the first six months of 2024, compared with the year-ago period. The following items contributed to the increase:

•A $58 million increase due to lower income tax payments to Ameren (parent), pursuant to the tax allocation agreement, primarily due to lower taxable income compared to the year-ago period.

•A $27 million increase resulting from increased customer collections primarily from base rate increases effective November 28, 2023, pursuant to the November 2023 natural gas rate order and electric transmission rate base growth and by increased customer collections under cost recovery mechanisms.

•A $22 million increase due to insurance proceeds received related to workers’ compensation payments made in 2023.

•An $18 million increase due to workers’ compensation payments made in the year-ago period.

•A $12 million increase due to the timing of payments for accounts payable.

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The following items partially offset the increase in Ameren Illinois’ cash from operating activities between periods:

•A $48 million increase in net collateral posted with counterparties, primarily due to changes in the market prices of natural gas.

•A $30 million increase in the cost of natural gas held in storage because of higher volumes, partially offset by lower commodity prices.

•An $18 million increase in interest payments, primarily due to an increase in the average outstanding debt and an increase in interest rates.

Cash Flows from Investing Activities

Ameren’s cash used in investing activities increased $43 million during the first six months of 2024, compared with the year-ago period, primarily as a result of a $70 million increase in capital expenditures, largely resulting from the acquisition of the Cass County Solar Project at Ameren Missouri, partially offset by decreased expenditures for electric transmission infrastructure upgrades at Ameren Illinois. Ameren’s increase in capital expenditures was also partially offset by decreased expenditures for electric distribution infrastructure upgrades and natural gas infrastructure at Ameren Illinois due to steps taken by Ameren Illinois to align its 2024 operations with the ICC’s MYRP orders and November 2023 natural gas rate order. Ameren’s increase in cash used in investing activities was partially offset by a $13 million decrease due to the timing of nuclear fuel expenditures at Ameren Missouri.

Ameren Missouri’s cash used in investing activities increased $175 million during the first six months of 2024, compared with the year-ago period, primarily as a result of a $190 million increase in capital expenditures, largely resulting from the acquisition of the Cass County Solar Project. Ameren Missouri’s increase in cash used in investing activities was partially offset by a $13 million decrease due to the timing of nuclear fuel expenditures.

Ameren Illinois’ cash used in investing activities decreased $104 million during the first six months of 2024, compared with the year-ago period, primarily as a result of a $127 million decrease in capital expenditures, largely resulting from decreased expenditures for electric transmission infrastructure upgrades. Ameren Illinois’ capital expenditures also decreased as a result of reduced expenditures for electric distribution infrastructure upgrades and natural gas infrastructure due to steps taken by Ameren Illinois to align its 2024 operations with the ICC’s MYRP orders and November 2023 natural gas rate order. Ameren Illinois’ decrease in cash used in investing activities was partially offset by a $30 million increase in net money pool advances.

Cash Flows from Financing Activities

Cash provided by, or used in, financing activities is a result of our financing needs, which depend on the level of cash provided by operating activities, the level of cash used in investing activities, the level of dividends, and our long-term debt maturities, among other things.

Ameren’s cash provided by consolidated financing activities increased $104 million during the first six months of 2024, compared with the year-ago period. During the first six months of 2024, Ameren utilized net proceeds from the issuance of long-term debt of $1,470 million for capital expenditures and to repay then-outstanding short-term debt. In addition, during the first six months of 2024, Ameren utilized proceeds from net commercial paper issuances of $156 million along with cash provided by operating activities to fund, in part, capital expenditures. Ameren also repaid $350 million of long-term debt maturities during the first six months of 2024. In comparison, during the first six months of 2023, Ameren utilized net proceeds from the issuance of long-term debt of $997 million for capital expenditures, to repay then-outstanding short-term debt, and to repay $100 million of long-term debt maturities. In addition, during the first six months of 2023, Ameren utilized proceeds from net commercial paper issuances of $260 million along with cash provided by operating activities to fund, in part, capital expenditures. During the first six months of 2024, Ameren paid common stock dividends of $356 million, compared with $330 million in the year-ago period, as a result of an increase in both the dividend rate and the number of common shares outstanding.

Ameren Missouri’s cash provided by financing activities increased $217 million during the first six months of 2024, compared with the year-ago period. During the first six months of 2024, Ameren Missouri utilized net proceeds from the issuance of long-term debt of $846 million for capital expenditures and to repay then-outstanding short-term debt. Additionally, during the first six months of 2024, Ameren Missouri utilized net commercial paper issuances totaling $220 million, capital contributions from Ameren (parent) of $350 million, and cash provided by operating activities to fund, in part, capital expenditures. Ameren Missouri also repaid $350 million of long-term debt maturities and $306 million of money pool borrowings during the first six months of 2024. In comparison, during the first six months of 2023, Ameren Missouri utilized net proceeds from the issuance of long-term debt of $499 million for capital expenditures and to repay then-outstanding short-term debt. In addition, during the first six months of 2023, Ameren Missouri utilized proceeds from net commercial paper issuances of $44 million and cash provided by operating activities to fund, in part, capital expenditures.

Ameren Illinois’ cash provided by financing activities decreased $157 million during the first six months of 2024, compared with the year-ago period. During the first six months of 2024, Ameren Illinois utilized proceeds from the issuance of long-term debt of $624 million to repay then-outstanding short-term debt. In addition, during the first six months of 2024, Ameren Illinois repaid net commercial paper borrowings of $366 million and money pool borrowings of $135 million. In comparison, during the first six months of 2023, Ameren Illinois utilized net proceeds from the issuance of long-term debt of $498 million to repay then-outstanding short-term debt and $100 million of long-term debt

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maturities. In addition, during the first six months of 2023, Ameren Illinois repaid net commercial paper borrowings totaling $147 million. During the first six months of 2024, Ameren Illinois also paid common stock dividends of $25 million.

See Long-term Debt and Equity in this section for additional information on maturities and issuances of long-term debt, issuances of common stock, and noncash settlement of a financing obligation.

Credit Facility Borrowings and Liquidity

The following table presents Ameren’s consolidated liquidity as of June 30, 2024:

	Available at June 30, 2024
Ameren (parent) and Ameren Missouri:
Missouri Credit Agreement – borrowing capacity	$	1,400
Less: Ameren (parent) commercial paper outstanding	177
Less: Ameren Missouri commercial paper outstanding	390
Less: Letters of credit	7
Missouri Credit Agreement – subtotal	826
Ameren (parent) and Ameren Illinois:
Illinois Credit Agreement – borrowing capacity	1,200
Less: Ameren (parent) commercial paper outstanding	124
Less: Ameren Illinois letters of credit	1
Illinois Credit Agreement – subtotal	1,075
Subtotal	$	1,901
Add: Cash and cash equivalents	19
Net Available Liquidity(a)	$	1,920

(a)Does not include Ameren’s forward equity sale agreements. See Note 4 – Long-term Debt and Equity Financings under Part I, Item 1, of this report for additional information.

The Credit Agreements, among other things, provide $2.6 billion of credit until maturity in December 2027. See Note 3 – Short-term Debt and Liquidity under Part I, Item 1, of this report for additional information on the Credit Agreements. During the six months ended June 30, 2024, Ameren (parent), Ameren Missouri, and Ameren Illinois each issued commercial paper. Borrowings under the Credit Agreements and commercial paper issuances are based upon available interest rates at the time of the borrowing or issuance.

Ameren has a money pool agreement with and among its utility subsidiaries to coordinate and to provide for certain short-term cash and working capital requirements. As short-term capital needs arise, and based on availability of funding sources, Ameren Missouri and Ameren Illinois will access funds from the utility money pool, the Credit Agreements, or the commercial paper programs depending on which option has the lowest interest rates.

See Note 3 – Short-term Debt and Liquidity under Part I, Item 1, of this report for additional information on credit agreements, commercial paper issuances, Ameren’s money pool agreements and related borrowings, and relevant interest rates.

The issuance of short-term debt securities by Ameren’s utility subsidiaries is subject to FERC approval under the Federal Power Act. In January 2023, the FERC issued orders authorizing Ameren Missouri, Ameren Illinois, and ATXI to issue up to $1 billion, $1 billion, and $300 million, respectively, of short-term debt securities through January 2025.

The Ameren Companies continually evaluate the adequacy and appropriateness of their liquidity arrangements for changing business conditions. When business conditions warrant, changes may be made to existing credit agreements or to other borrowing arrangements, or other arrangements may be made.

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Long-term Debt and Equity

The following table presents issuances (net of any issuance premiums or discounts) of long-term debt and equity, as well as maturities of long-term debt for the six months ended June 30, 2024 and 2023:

	Month Issued, Redeemed, or Matured	2024		2023
Issuances of Long-term Debt
Ameren Missouri:
5.25% First mortgage bonds due 2054	January	$	347	$	—
5.45% First mortgage bonds due 2053	March	—		499
5.20% First mortgage bonds due 2034	April	499		—
Ameren Illinois:
4.95% First mortgage bonds due 2033	May	—		498
5.55% First mortgage bonds due 2054	June	624		—
Total Ameren long-term debt issuances		$	1,470	$	997
Issuances of Common Stock
Ameren:
DRPlus and 401(k)(a)(b)	Various	$	21	$	16
Total Ameren common stock issuances(c)		$	21	$	16
Maturities of Long-term Debt
Ameren Missouri:
Audrain County agreement (Audrain County CT) due 2023	January	$	—	$	240	(d)
3.50% Senior secured notes due 2024	April	350		—
Ameren Illinois:
0.375% First mortgage bonds due 2023	June	—		100
Total Ameren long-term debt maturities		$	350	$	340

(a)Ameren issued a total of 0.3 million and 0.2 million shares of common stock under its DRPlus and 401(k) plan for the six months ended June 30, 2024 and 2023, respectively.

(b)Excludes a $7 million and $7 million receivable at June 30, 2024 and 2023, respectively.

(c)Excludes 0.2 million and 0.5 million shares of common stock valued at $16 million and $37 million issued for no cash consideration in connection with stock-based compensation for the six months ended June 30, 2024 and 2023, respectively.

(d)In January 2023, Ameren Missouri and Audrain County mutually agreed to terminate a financing obligation agreement related to the CT energy center in Audrain County, which was scheduled to expire in December 2023. No cash was exchanged in connection with the termination of the agreement as the $240 million principal amount of the financing obligation due from Ameren Missouri was equal to the amount of bond service payments due to Ameren Missouri.

See Note 4 – Long-term Debt and Equity Financings under Part I, Item 1, of this report for additional information, including proceeds from issuances of long-term debt, the use of those proceeds, Ameren’s forward equity sale agreements, the ATM program, and capital contributions received by Ameren Missouri from Ameren (parent).

Indebtedness Provisions and Other Covenants

At June 30, 2024, the Ameren Companies were in compliance with the provisions and covenants contained in their credit agreements, indentures, and articles of incorporation, as applicable, and ATXI was in compliance with the provisions and covenants contained in its note purchase agreements. See Note 3 – Short-term Debt and Liquidity under Part I, Item 1, of this report and Note 4 – Short-term Debt and Liquidity and Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of the Form 10-K for a discussion of provisions, applicable cross-default provisions, and covenants contained in our credit agreements, in ATXI’s note purchase agreements, and in certain of the Ameren Companies’ indentures and articles of incorporation.

We consider access to short-term and long-term capital and credit markets to be a significant source of funding for capital requirements not satisfied by cash provided by our operating activities. Inability to raise capital on reasonable terms, particularly during times of uncertainty in the capital and credit markets, could negatively affect our ability to maintain and expand our businesses. After assessing their respective current operating performance, liquidity, and credit ratings (see Credit Ratings below), Ameren, Ameren Missouri, and Ameren Illinois each believes that it will continue to have access to the capital and credit markets on reasonable terms. However, events beyond Ameren’s, Ameren Missouri’s, and Ameren Illinois’ control may create uncertainty in the capital and credit markets or make access to the capital and credit markets uncertain or limited. Such events could increase our cost of capital and adversely affect our ability to access the capital and credit markets.

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Dividends

The amount and timing of dividends payable on Ameren’s common stock are within the sole discretion of Ameren’s board of directors. Ameren’s board of directors has not set specific targets or payout parameters when declaring common stock dividends, but it considers various factors, including Ameren’s overall payout ratio, payout ratios of our peers, projected cash flow and potential future cash flow requirements, historical earnings and cash flow, projected earnings, impacts of regulatory orders or legislation, and other key business considerations. Ameren expects its dividend payout ratio to be between 55% and 65% of annual earnings over the next few years.

See Note 4 – Short-term Debt and Liquidity and Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of the Form 10-K for additional discussion of covenants and provisions contained in certain of the Ameren Companies’ financial agreements and articles of incorporation that would restrict the Ameren Companies’ payment of dividends in certain circumstances. At June 30, 2024, none of these circumstances existed at Ameren, Ameren Missouri, or Ameren Illinois and, as a result, these companies were not restricted from paying dividends.

The following table presents common stock dividends declared and paid by Ameren Corporation to its common shareholders and by Ameren subsidiaries to their parent, Ameren Corporation, for the six months ended June 30, 2024 and 2023:

	Six Months
	2024		2023
Ameren	$	356	$	330
Ameren Illinois	25		—
ATXI	—		75

Credit Ratings

Our credit ratings affect our liquidity, our access to the capital and credit markets, our cost of borrowing under our credit facilities and our commercial paper programs, and our collateral posting requirements under commodity contracts.

The following table presents the principal credit ratings by Moody’s and S&P, as applicable, effective on the date of this report:

	Moody’s	S&P
Ameren:
Issuer/corporate credit rating	Baa1	BBB+
Senior unsecured debt	Baa1	BBB
Commercial paper	P-2	A-2
Ameren Missouri:
Issuer/corporate credit rating	Baa1	BBB+
Secured debt	A2	A
Senior unsecured debt	Baa1	Not Rated
Commercial paper	P-2	A-2
Ameren Illinois:
Issuer/corporate credit rating	A3	BBB+
Secured debt	A1	A
Senior unsecured debt	A3	BBB+
Commercial paper	P-2	A-2
ATXI:
Issuer credit rating	A2	Not Rated
Senior unsecured debt	A2	Not Rated

A credit rating is not a recommendation to buy, sell, or hold securities. It should be evaluated independently of any other rating. Ratings are subject to revision or withdrawal at any time by the rating organization.

Collateral Postings

Any weakening of our credit ratings may reduce access to capital and trigger additional collateral postings and prepayments. Such changes may also increase the cost of borrowing, resulting in an adverse effect on earnings. Cash collateral postings and prepayments made with external parties, including postings related to exchange-traded contracts were immaterial and cash collateral posted by external parties were $53 million for Ameren and Ameren Illinois at June 30, 2024. A sub-investment-grade issuer or senior unsecured debt rating (below “Baa3” from Moody’s or below “BBB-” from S&P) at June 30, 2024, could have resulted in Ameren, Ameren Missouri, or Ameren Illinois being

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required to post additional collateral or other assurances for certain trade and contractual obligations amounting to $654 million, $559 million, and $95 million, respectively.

Changes in commodity prices could trigger additional collateral postings and prepayments. Based on credit ratings at June 30, 2024, if market prices were 15% higher or lower than June 30, 2024 levels in the next 12 months and 20% higher or lower thereafter through the end of the term of the commodity contracts, then Ameren, Ameren Missouri, and Ameren Illinois could be required to post an immaterial amount, compared to each company’s liquidity, of collateral or provide other assurances for certain trade and contractual obligations.

OUTLOOK

Below are some key trends, events, and uncertainties that may reasonably affect our results of operations, financial condition, or liquidity, as well as our ability to achieve strategic and financial objectives, for 2024 and beyond. For additional information regarding recent rate orders, lawsuits, and pending requests filed with state and federal regulatory commissions, including those discussed below, see Note 2 – Rate and Regulatory Matters under Part I, Item 1, of this report and Note 2 – Rate and Regulatory Matters under Part II, Item 8, of the Form 10-K.

Operations

•The PISA permits Ameren Missouri to defer and recover 85% of the depreciation expense for investments in qualifying property, plant, and equipment placed in service and not included in base rates. Investments not eligible for recovery under the PISA include amounts related to new nuclear and natural gas generating units and service to new customer premises. Additionally, the PISA permits Ameren Missouri to earn a return at the applicable WACC on rate base that incorporates those qualifying investments, as well as changes in total accumulated depreciation excluding retirements and plant-related deferred income taxes since the previous regulatory rate review. The regulatory asset for accumulated PISA deferrals also earns a return at the applicable WACC until added to rate base prospectively. Ameren Missouri recognizes an offset to “Interest Charges” on its consolidated statement of income for its carrying cost of debt relating to each return allowed under the PISA, with the difference between the applicable WACC and its carrying cost of debt recognized in revenues when recovery of PISA deferrals is reflected in customer rates. Approved PISA deferrals are recovered over a period of 20 years following a regulatory rate review. Additionally, under the RESRAM, Ameren Missouri is permitted to recover the 15% of depreciation expense not recovered under the PISA, and earn a return at the applicable WACC for investments in renewable generation plant placed in service to comply with Missouri’s renewable energy standard. Accumulated RESRAM deferrals earn carrying costs at short-term interest rates. The PISA and the RESRAM mitigate the effects of regulatory lag between regulatory rate reviews. Those investments not eligible for recovery under the PISA and the remaining 15% of certain property, plant, and equipment placed in service, unless eligible for recovery under the RESRAM, remain subject to regulatory lag. As a result of the PISA election, additional provisions of the law apply to Ameren Missouri, including limitations on electric customer rate increases. Pursuant to a Missouri law that became effective in August 2022, Ameren Missouri’s PISA election was extended through December 2028 and an additional extension through December 2033 is allowed if requested by Ameren Missouri and approved by the MoPSC, among other things. This law also established a 2.5% annual limit on increases to the electric service revenue requirement used to set customer rates, compared to the revenue requirement established in the immediately preceding rate order, due to the inclusion of incremental PISA deferrals in the revenue requirement. The limitation will be effective for revenue requirements approved by the MoPSC after January 1, 2024.

•In June 2023, the MoPSC issued an order that resulted in an increase of $140 million to Ameren Missouri’s annual revenue requirement for electric retail service. The order increased the annualized base level of net energy costs pursuant to the FAC by approximately $40 million from the base level established in the MoPSC’s December 2021 electric rate order. The order also changed annualized depreciation, regulatory asset and liability amortization amounts, and the base level of expenses for trackers. On an annualized basis, these changes reflect approximate increases in “Depreciation and amortization” of $90 million and “Other income, net”, of $100 million, related to non-service pension and postretirement benefit income, on Ameren’s and Ameren Missouri’s consolidated statements of income. The new rates became effective on July 9, 2023. As a result of this order, Ameren Missouri expects a year-over-year increase to 2024 earnings, compared to 2023, of approximately $26 million ($10 million and $13 million realized in the first and second quarters, respectively, and $3 million expected in the third quarter).

•In June 2024, Ameren Missouri filed a request with the MoPSC seeking approval to increase its annual revenues for electric service by $446 million. The MoPSC proceeding relating to the proposed electric service rate changes will take place over a period of up to 11 months, with a decision by the MoPSC expected by May 2025 and new rates effective by June 2025. Ameren Missouri cannot predict the level of any electric service rate change the MoPSC may approve, whether the requested regulatory recovery mechanisms will be continued, or whether any rate change that may eventually be approved will be sufficient for Ameren Missouri to recover its costs and earn a reasonable return on its investments when the rate change goes into effect.

•Ameren Missouri expects to file for a natural gas regulatory rate review by the end of August 2024. Ameren Missouri expects the primary driver of the natural gas service regulatory rate review to be increased infrastructure investments.

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•In 2018, the MoPSC issued an order approving Ameren Missouri’s MEEIA 2019 plan. The plan includes a portfolio of customer energy-efficiency and demand response programs through December 2024. Ameren Missouri intends to invest approximately $420 million over the life of the plan, including $76 million in 2024. The plan includes the continued use of the MEEIA rider, which allows Ameren Missouri to collect from customers its actual MEEIA program costs and related lost electric revenues. In addition, the plan includes a performance incentive that provides Ameren Missouri an opportunity to earn revenues by achieving certain customer energy-efficiency goals. If the target program spending goal is achieved for 2024, the performance incentive would result in revenues of $12 million in 2024.

•In January 2024, Ameren Missouri filed a proposed customer energy-efficiency plan with the MoPSC under the MEEIA. This filing proposed a three-year plan, which includes a portfolio of customer energy-efficiency programs, along with the continued use of the MEEIA rider discussed above. If the plan is approved, Ameren Missouri intends to invest $123 million annually in the proposed customer energy-efficiency programs from 2025 to 2027. In addition, Ameren Missouri requested performance incentives applicable to each plan year to earn revenues by achieving certain customer energy-efficiency savings and target spending goals. If 100% of the goals are achieved, Ameren Missouri would earn performance incentive revenues totaling $56 million over the three-year plan. Ameren Missouri also requested additional performance incentives applicable to each plan year totaling up to $14 million over the three-year plan, if Ameren Missouri exceeds 100% of the goals. In March 2024, the MoPSC staff and the MoOPC filed responses in opposition to the proposed customer energy-efficiency plan under the MEEIA. Ameren Missouri expects a decision by the MoPSC by October 2024, but cannot predict the ultimate outcome of this regulatory proceeding.

•Ameren Illinois and ATXI use a forward-looking rate calculation with an annual revenue requirement reconciliation for each company’s electric transmission business. Based on expected rate base and the currently allowed 10.52% ROE, which includes a 50-basis-point incentive adder for participation in an RTO, the revenue requirements that are included in 2024 rates for Ameren Illinois’ and ATXI’s electric transmission businesses are $549 million and $223 million, respectively. These revenue requirements represent increases in Ameren Illinois’ and ATXI’s revenue requirements of $73 million and $29 million, respectively, from the revenue requirements reflected in 2023 rates, primarily due to higher expected rate base. These rates will affect Ameren Illinois’ and ATXI’s cash receipts during 2024, but will not determine their respective electric transmission service operating revenues, which will instead be based on 2024 actual recoverable costs, rate base, and a return on rate base at the applicable WACC as calculated under the FERC formula ratemaking framework.

•The allowed base ROE for FERC-regulated transmission rates previously charged under the MISO tariff has been the subject of pending proceedings since 2013. Depending on the outcome of the proceedings, the transmission rates charged during previous periods and the currently effective rates may be subject to change and refund. In March 2020, the FERC issued a Notice of Proposed Rulemaking on its transmission incentives policy, which increased the incentive ROE for participation in an RTO to 100 basis points from the current 50 basis points and revised the parameters for awarding incentives, while limiting the overall incentives to a cap of 250 basis points, among other things. In April 2021, the FERC issued a Supplemental Notice of Proposed Rulemaking, which proposed to modify the Notice of Proposed Rulemaking’s incentive for participation in an RTO by limiting this incentive for utilities that join an RTO to 50 basis points and only allowing them to earn the incentive for three years, among other things. If this proposal is included in a final rule, Ameren Illinois and ATXI would no longer be eligible for the 50 basis point RTO incentive adder, prospectively. The FERC is under no deadline to issue a final rule on this matter. Ameren is unable to predict the ultimate impact of any changes to the FERC’s incentives policy, or any further order on base ROE. A 50-basis-point change in the FERC-allowed ROE would affect Ameren’s and Ameren Illinois’ annual net income by an estimated $16 million and $11 million, respectively, based on each company’s 2024 projected rate base.

•Pursuant to December 2022 and March 2021 ICC orders, Ameren Illinois used the IEIMA formula framework to establish annual electric distribution service rates effective through 2023, and reconciled the related revenue requirement for customer rates established for 2023. As such, Ameren Illinois’ 2023 revenues reflected actual recoverable costs, year-end rate base, and a return at the applicable WACC, with the ROE component based on the annual average of the monthly yields of the 30-year United States Treasury bonds plus 580 basis points. By law, the decoupling provisions extend beyond 2023, which ensures that Ameren Illinois’ electric distribution revenues authorized in a regulatory rate review are not affected by changes in sales volumes. In April 2024, Ameren Illinois filed for a reconciliation adjustment to its 2023 electric distribution service revenue requirement with the ICC. In July 2024, Ameren Illinois filed a revised reconciliation adjustment, requesting recovery of $158 million. An ICC decision in this proceeding is required by December 2024, and any approved adjustment would be collected from customers in 2025. This is the final revenue requirement reconciliation under the IEIMA formula framework.

•Pursuant to the CEJA, which was enacted in September 2021, Ameren Illinois may file an MYRP with the ICC to establish base rates for electric distribution service to be charged to customers for each calendar year of a four-year period. The base rates for a particular calendar year are based on forecasted recoverable costs and an ICC-determined ROE applied to Ameren Illinois’ forecasted average annual rate base using a forecasted capital structure, with a common equity ratio of up to 50% being deemed prudent and reasonable by law and a higher equity ratio requiring specific ICC approval. The ROE determined by the ICC for each calendar year of the four-year period is subject to annual adjustments based on certain performance incentives and penalties. An MYRP allows Ameren Illinois to reconcile electric distribution service rates to its actual revenue requirement on an annual basis, subject to a reconciliation cap and

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adjustments to the ROE. Under the MYRP discussed below, Ameren Illinois’ 2024 electric distribution service revenues will be based on its 2024 actual recoverable costs, 2024 year-end rate base, and an ROE of 8.72%, as adjusted for any performance incentives or penalties, provided the actual revenue requirement does not exceed the reconciliation cap. If a given year’s revenue amount collected from customers varies from the approved revenue requirement, an adjustment is made to electric operating revenues with an offset to a regulatory asset or liability to reflect that year’s actual revenue requirement, independent of actual sales volumes. The regulatory balance is then collected from, or refunded to, customers within two years from the end of the applicable annual period. Ameren Illinois’ existing riders remain effective under the MYRP discussed below, and will continue to remain effective beyond 2027 whether it elects to file an MYRP or a traditional regulatory rate review. Additionally, electric distribution service revenues continue to be decoupled from sales volumes under either election.

•In December 2023, the ICC issued an order in Ameren Illinois' MYRP proceeding approving base rates for electric distribution services for 2024 through 2027 and rejecting Ameren Illinois' Grid Plan, which was addressed as part of the MYRP proceeding. Rate changes consistent with the December 2023 order became effective in January 2024 and remained effective through late June 2024, when new rates became effective pursuant to the June 2024 ICC rehearing order discussed below. The December 2023 order adopted an alternative methodology to establish a rate base and revenue requirements for the years 2024 through 2027 using Ameren Illinois’ previously approved 2022 year-end rate base. In January 2024, the ICC partially denied a rehearing requested by Ameren Illinois to revise the allowed ROE in the December 2023 order and granted Ameren Illinois’ rehearing request to reconsider the rate base for each year of the MYRP and to include a base level of investments to maintain grid reliability in each year of the MYRP. In June 2024, the ICC issued an order on Ameren Illinois’ rehearing request, approving revenue requirements for electric distribution services for 2024, 2025, 2026, and 2027 of $1,196 million, $1,282 million, $1,350 million, and $1,397 million, respectively. New rates became effective in late June 2024. In July 2024, Ameren Illinois filed a request for rehearing of the ICC’s June 2024 rehearing order to include an asset associated with other postretirement benefits in the rate base. Subsequently, in August 2024, the ICC denied the rehearing request. The ICC rehearing denial is subject to appeal. Using the 2023 revenue requirement as a starting point, the approved revenue requirements in the ICC’s June 2024 rehearing order represent a cumulative four-year increase of $285 million. In January 2024, Ameren Illinois filed an appeal of the December 2023 ICC order to the Illinois Appellate Court for the Fifth Judicial District. The court is under no deadline to address the appeal. In July 2024, Ameren Illinois filed an update to its revised Grid Plan and a request to update the associated MYRP revenue requirements for 2024, 2025, 2026, and 2027 to $1,215 million, $1,300 million, $1,386 million, and $1,446 million, respectively. An ICC decision on the revised Grid Plan and updated revenue requirements is expected by the end of 2024 with rates effective in January 2025. Using the 2023 revenue requirement as a starting point, the requested revenue requirements in Ameren Illinois’ July 2024 revised MYRP filing represent a cumulative four-year increase of $334 million. Ameren Illinois cannot predict the ultimate outcome of the appeal to the Illinois Appellate Court for the Fifth Judicial District, its revised Grid Plan filing, or its request to update the associated MYRP revenue requirements for 2024 through 2027. Ameren Illinois has taken prudent steps to align its 2024 operations with the ICC orders, while continuing to ensure safe and adequate service is maintained. This includes reductions to Ameren Illinois’ capital expenditure and operations and maintenance expense plans.

•Pursuant to Illinois law, Ameren Illinois’ electric energy-efficiency investments are deferred as a regulatory asset and earn a return at the applicable WACC, with the ROE component based on the annual average of the monthly yields of the 30-year United States Treasury bonds plus 580 basis points. The allowed ROE 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. While the ICC has approved a plan for Ameren Illinois to invest approximately $120 million per year in electric energy-efficiency programs through 2025, the ICC has the ability to reduce the amount of electric energy-efficiency savings goals in future program years if there are insufficient cost-effective programs available, which could reduce the investments in electric energy-efficiency programs. The electric energy-efficiency program investments and the return on those investments are collected from customers through a rider.

•In November 2023, the ICC issued an order in Ameren Illinois’ January 2023 natural gas delivery service regulatory rate review, which resulted in an increase to its annual revenues for natural gas delivery service of $112 million. The new rates became effective on November 28, 2023. In December 2023, Ameren Illinois filed a request for rehearing with the ICC to revise the approved ROE and capital structure common equity percentage, and reverse an approximately $93 million reduction of planned distribution and transmission capital investments included in the order, among other things. In January 2024, the ICC denied Ameren Illinois’ rehearing request. Subsequently, in January 2024, Ameren Illinois filed an appeal of the November 2023 ICC order to the Illinois Appellate Court for the Fifth Judicial District. The court is under no deadline to address the appeal. Ameren Illinois cannot predict the ultimate outcome of this appeal. Ameren Illinois has taken prudent steps to align its 2024 operations with the ICC order, while continuing to ensure safe and adequate service is maintained. This includes reductions to Ameren Illinois’ capital expenditure and operations and maintenance expense plans.

•Ameren Missouri’s next refueling and maintenance outage at its Callaway energy center is scheduled for the spring of 2025. During a scheduled refueling, which occurs every 18 months, maintenance expenses are deferred as a regulatory asset and amortized until the completion of the next refueling and maintenance outage. During an outage, depending on the availability of its other generation sources and the market prices for power, Ameren Missouri’s purchased power costs may increase and the amount of excess power available for

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sale may decrease versus non-outage years. Changes in purchased power costs and excess power available for sale are included in the FAC, which results in limited impacts to earnings. In addition, Ameren Missouri may incur increased non-nuclear energy center maintenance costs in non-outage years.

•In September 2023, the United States District Court for the Eastern District of Missouri granted Ameren Missouri’s request to modify a September 2019 remedy order issued by the district court in order to allow the retirement of the Rush Island Energy Center in advance of its previously expected retirement date of 2039, in lieu of installing a flue gas desulfurization system. In its amended remedy order, the district court established an October 15, 2024 retirement date to allow for the completion of various transmission reliability projects and, in the interim, authorized Ameren Missouri to operate the energy center only as needed and as directed by the MISO. The MISO designated the Rush Island Energy Center as a system support resource in 2022 and concluded that certain reliability mitigation measures, including transmission upgrades, should occur before the energy center is retired. The Rush Island Energy Center began operating as a system support resource on September 1, 2022. In 2024, the MISO extended the system support resource designation through Rush Island Energy Center’s retirement date of October 15, 2024. In July 2024, an agreement between Ameren Missouri and the MISO was filed with the FERC for approval regarding the continued operation of the energy center during peak demand times and emergencies. Construction activities are ongoing for the transmission upgrades approved by the MISO, with the majority of the upgrades expected to be completed in the fall of 2024. Ameren Missouri expects to complete the last of the necessary upgrades by mid-2025. The United States Department of Justice is seeking an order from the district court providing for additional mitigation relief related to prior emissions. Ameren Missouri contends that the retirement of the Rush Island Energy Center, which eliminates all future emissions from the energy center, mitigates claims relating to prior emissions. In March 2024, the district court ordered Ameren Missouri and the United States Department of Justice to file proposed draft orders outlining additional mitigation relief. In May 2024, Ameren Missouri filed a proposed draft order that includes retiring the Rush Island Energy Center, a program to provide electric buses and charging stations to schools in the metro St. Louis area, a program to provide air filters to eligible Ameren Missouri electric residential customers, and the retirement of SO2 allowances. Excluding the accelerated retirement of the Rush Island Energy Center, these programs are estimated to cost approximately $20 million. Also in May 2024, the United States Department of Justice filed a proposed draft order that includes a program to provide electric buses and charging stations to schools in the metro St. Louis area and a program to provide air filters to eligible Ameren Missouri electric residential customers. These programs include a significantly greater number of buses, charging stations, and air filters than Ameren Missouri’s proposal and the United States Department of Justice estimates these programs would cost approximately $120 million. A mediation proceeding related to the potential additional mitigation relief is scheduled for September 2024. As of June 30, 2024, Ameren and Ameren Missouri recorded a $20 million liability related to the cost of potential additional mitigation, which represents the estimated minimum liability, as no other amount within the range was a better estimate. Ameren Missouri could be required to implement some or all of the additional mitigation relief programs included in the United States Department of Justice’s proposed draft order, the costs of which could be material and could adversely impact Ameren and Ameren Missouri’s results of operations and financial position. Depending on the scope and basis of any final order issued by the district court, which is expected by the end of 2024, Ameren Missouri or the United States Department of Justice could appeal any additional mitigation relief ordered. For additional information on the NSR and Clean Air Act litigation, see Note 9 – Commitments and Contingencies under Part I, Item 1, of this report. As part of the assessment of any potential future abandonment loss, consideration will be given to the Rush Island securitization order discussed below.

•Pursuant to Illinois law, Ameren Missouri's natural gas-fired energy centers in Illinois are subject to annual limits on emissions, including CO2 and NOx. Further reductions to emissions limits will become effective between 2030 and 2040, resulting in the closure of the Venice Energy Center by the end of 2029. The reductions could also limit the operations of Ameren Missouri's four other natural gas-fired energy centers located in the state of Illinois, and will result in their closure by 2040. These energy centers are utilized to support peak loads. Subject to conditions in the CEJA, these energy centers may be allowed to exceed the emissions limits in order to maintain reliability of electric utility service.

•Although the pace of inflation has slowed recently, we are still observing elevated inflation levels that continue to put pressure on the prices of labor, services, materials, and supplies, as well as high interest rates. Ameren Missouri and Ameren Illinois are generally allowed to pass on to customers prudently incurred costs for fuel, purchased power, and natural gas supply. Additionally, for certain non-commodity cost changes, the use of trackers, riders, formula ratemaking, and future test years, as applicable, mitigates our exposure. The elevated inflation levels and high interest rates could impact our ability to control costs and/or make substantial investments in our businesses, including our ability to recover costs and investments, and to earn our allowed ROEs within frameworks established by our regulators, while maintaining rates that are affordable to our customers. In addition, the elevated inflation levels and high interest rates could adversely affect our customers’ usage of, or payment for, our services.

•Ameren Missouri and Ameren Illinois continue to make infrastructure investments and expect to seek increases to electric and natural gas rates to recover the cost of investments and earn an adequate return. Ameren Missouri and Ameren Illinois will also seek new, or to maintain existing, regulatory and legislative solutions to address regulatory lag and to support investment in their utility infrastructure for the benefit of their customers. Ameren Missouri and Ameren Illinois continue to face cost recovery pressures, elevated inflation levels, higher cost of debt, customer conservation efforts, the impacts of additional customer energy-efficiency programs, and increased

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customer use of increasingly cost-effective advancements in innovative energy technologies, including private generation and energy storage. We expect a net increase in demand resulting from the electrification of the economy, including in the transportation sector. In addition, a new 250-MW data center is expected to be constructed in Ameren Missouri’s service territory and is expected to be in service by 2026, and several other entities in various industries, including data center and manufacturing, are considering either locating or expanding their operations within our service territories. We expect that increased investments, including expected future investments for environmental compliance, system reliability improvements, and new generation sources, will result in rate base and revenue growth but also higher depreciation and financing costs.

Liquidity and Capital Resources

•In September 2023, Ameren Missouri filed its 2023 IRP with the MoPSC, which includes Ameren Missouri’s preferred plan for meeting customers’ projected long-term energy needs in a manner that maintains system reliability and customer affordability while transitioning to clean energy generation in an environmentally responsible manner. In connection with this plan, Ameren is continuing to target net-zero carbon emissions by 2045, as well as a 60% reduction by 2030 and an 85% reduction by 2040 based on 2005 levels. Ameren’s goals include both reduction of direct emissions from operations (scope 1), as well as electricity usage at Ameren buildings (scope 2), including other greenhouse gas emissions of methane, nitrous oxide, and sulfur hexafluoride. Achieving these goals will be dependent on a variety of factors, including cost-effective advancements in innovative clean energy technologies and constructive federal and state energy and economic policies. The preferred plan includes, among other things, the following:

•adding an 800-MW natural gas-fired simple-cycle energy center by 2027, which will be realized through the Castle Bluff Natural Gas Project discussed below, and an additional 1,200-MW natural gas-fired combined-cycle energy center by 2033;

•adding 2,800 MWs of renewable generation by 2030, which includes the solar generation facilities discussed below, and an additional 1,900 MWs by 2036;

•adding 400 MWs of battery storage by 2030 and an additional 400 MWs by 2035;

•adding 1,200 MWs of other clean dispatchable generation resources by 2040 and an additional 1,200 MWs by 2043;

•retiring all of Ameren Missouri’s coal-fired energy centers by 2042;

•accelerating the retirement date of the Rush Island coal-fired energy center from 2025 to 2024;

•extending the retirement date of the Sioux coal-fired energy center from 2030 to 2032 to ensure reliability during the transition to clean energy generation, which is subject to the approval of a change in depreciable lives of the energy center’s assets by the MoPSC;

•retiring 1,800 MWs of Ameren Missouri’s natural gas-fired energy centers by 2040 to comply with Illinois law;

•the continued implementation of customer energy-efficiency and demand response programs; and

•the expectation that Ameren Missouri will seek and receive NRC approval for an extension of the operating license for the Callaway Energy Center beyond its current 2044 expiration date.

Expected capital expenditures through 2028 related to the facilities discussed above are included in Ameren’s and Ameren Missouri’s expected capital investments discussed below. Ameren Missouri’s plan could be affected by, among other factors: Ameren Missouri’s ability to obtain CCNs from the MoPSC, and any other required approvals for the addition of renewable resources or natural gas-fired generation, retirement of energy centers, and new or continued customer energy-efficiency programs; the ability to enter into agreements for renewable or natural gas-fired generation and acquire or construct that generation at a reasonable cost; the ability of suppliers, contractors, and developers to meet contractual commitments and timely complete projects, which is dependent upon the availability of necessary labor, materials, and equipment, geopolitical conflict, or government actions, among other things; changes in the scope and timing of projects; the ability to qualify for, and use or transfer, federal production or investment tax credits; the cost of wind, solar, and other renewable generation and battery storage technologies; the cost of natural gas or hydrogen CT technologies; the ability to maintain system reliability during and after the transition to clean energy generation; new and/or changes in environmental regulations, including those related to CO2 and other greenhouse gas emissions; energy prices and demand; Ameren Missouri’s ability to obtain necessary rights-of-way, easements, and transmission interconnection agreements at an acceptable cost and in a timely fashion; the ability to earn an adequate return on invested capital; and the ability to raise capital on reasonable terms. A new data center is expected to be constructed in Ameren Missouri’s service territory by 2026 and several entities are considering either locating or expanding their operations within Ameren Missouri’s service territory. As such, Ameren Missouri currently expects to update its 2023 IRP by February 2025, following its evaluation of potential load growth and its generation portfolio. The next integrated resource plan is required to be filed by October 2026.

•In June 2024, the MoPSC issued a financing order authorizing the issuance of securitized utility tariff bonds by a wholly owned, special purpose subsidiary of Ameren Missouri to finance approximately $470 million of costs related to the planned accelerated retirement of the Rush Island Energy Center, which includes the expected remaining unrecovered net plant balance associated with the facility, among other costs. Ameren Missouri initially petitioned the MoPSC in November 2023 to finance $519 million of costs. The difference between the initial petition and final financing order will be considered for recovery in future rate proceedings involving the securitized utility tariff charge or base rates. Ameren Missouri will collect the amounts necessary to repay the bonds over approximately 15 years

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from the date of bond issuance. The financing order also includes a determination that the decision to retire the Rush Island Energy Center was reasonable and prudent. The MoPSC did not make a determination regarding the prudency of Ameren Missouri's prior actions that resulted in the adverse ruling in the NSR and Clean Air Act litigation discussed in Note 9 – Commitments and Contingencies under Part I, Item 1, of this report. However, claims regarding such actions could be considered in future regulatory proceedings. If future regulatory proceedings result in revenue reductions based on Ameren Missouri’s prior actions that resulted in the adverse ruling in the NSR and Clean Air Act litigation, it could have a material adverse effect on the results of operations, financial position, and liquidity of Ameren and Ameren Missouri. In July 2024, the MoOPC filed a request for rehearing of the financing order. Ameren Missouri expects a decision on the rehearing request in August 2024. The decision on the rehearing request is subject to appeal. The timing of the issuance of securitized utility tariff bonds is dependent on the conclusion of any appeal process.

•During 2022 and 2023, Ameren Missouri, and certain subsidiaries of Ameren Missouri, entered into agreements to acquire and/or construct various solar generation facilities. Most regulatory approvals have been obtained with the exception of FERC approval for the acquisition of the Split Rail Solar Project. In June 2024, Ameren Missouri acquired the Cass County Solar Project, which includes solar panels, project design, land rights, and engineering, procurement, and construction agreements, for approximately $250 million and took over construction management of the project. Also in June 2024, Ameren Missouri filed for a CCN with the MoPSC to construct the Castle Bluff Natural Gas Project. All of the generation facilities are aligned with the 2023 IRP discussed above, and expected capital expenditures related to these facilities are included in Ameren’s and Ameren Missouri’s expected capital investments discussed below.

•Through 2028, we expect to make significant capital expenditures to improve our electric and natural gas utility infrastructure, with a major portion directed to our transmission and distribution systems. We estimate that we will invest up to $22.8 billion (Ameren Missouri – up to $13.5 billion; Ameren Illinois – up to $7.6 billion; ATXI – up to $1.7 billion) of capital expenditures during the period from 2024 through 2028. Ameren’s and Ameren Missouri’s estimates include $3.3 billion of renewable generation investments and $2.7 billion of dispatchable generation investments through 2028, consistent with Ameren Missouri’s 2023 IRP. Ameren’s and Ameren Illinois’ estimates include investments necessary to meet compliance requirements of the CEJA, while continuing to ensure safe and adequate service is maintained. Ameren Illinois’ estimates may be revised as a result of future ICC orders related to its current MYRP.

•In 2021, the MISO issued a report outlining a preliminary long-range transmission planning roadmap of projects through 2039, which considers the rapidly changing generation mix within MISO resulting from significant additions of renewable generation, actual and expected generation plant closures, and state mandates or goals for clean energy or carbon emissions reductions. In July 2022, the MISO approved the first tranche of projects under the roadmap. A portion of these projects were assigned to various utilities, of which Ameren was awarded projects that are estimated to cost approximately $1.8 billion, based on the MISO’s cost estimate. Related to these projects, Ameren began substation upgrades in May 2024 in advance of transmission line construction, which is expected to begin in 2026, with forecasted completion dates near the end of this decade. In addition, MISO awarded two competitive bid projects to ATXI in the fourth quarter of 2023 and one in April 2024 that represent a total estimated investment of approximately $220 million for ATXI. In February 2024, Ameren Illinois and ATXI filed a request for a CCN, among other things, with the ICC related to the portion of the MISO long-range transmission projects they will construct within the ICC’s jurisdiction. A decision by the ICC is expected by mid-2025. In July 2024, ATXI filed a request for a CCN, among other things, with the MoPSC related to a portion of the MISO long-range transmission projects that it will construct within the MoPSC’s jurisdiction. A decision by the MoPSC is expected by mid-2025. In June 2024, the MISO revised a proposed first set of second tranche projects with estimated costs of $23 billion to $27 billion based on the MISO’s cost estimate. The MISO is expected to approve this set of projects by the end of 2024. The MISO expects to develop an additional set of second tranche projects in 2025.

•Environmental regulations, including those related to CO2 emissions, or other actions taken by the EPA or state regulators, or requirements that may result from the NSR and Clean Air Act Litigation, could result in significant increases in capital expenditures and operating costs. Regulations can be reviewed and repealed, and replacement or alternative regulations can be proposed or adopted by the regulatory agencies, including the EPA. See Note 9 – Commitments and Contingencies under Part I, Item 1, of this report, for additional information on environmental matters, including the NSR and Clean Air Act litigation. The ultimate implementation of any of these new regulations, as well as the timing of any such implementation, is uncertain. However, the individual or combined effects of existing and new environmental regulations could result in significant capital expenditures, increased operating costs, or the closure or alteration of some of Ameren Missouri’s coal and natural gas-fired energy centers. Ameren Missouri’s operating costs and capital expenditures are subject to MoPSC prudence reviews, which could result in cost disallowances, as well as regulatory lag. The cost of Ameren Illinois’ purchased power and natural gas purchased for resale could increase. However, Ameren Illinois expects that these costs would be recovered from customers with no material adverse effect on its results of operations, financial position, or liquidity. Ameren’s and Ameren Missouri’s earnings could benefit from increased investment to comply with environmental regulations if those investments are reflected and recovered on a timely basis in customer rates.

•The Ameren Companies have multiyear credit agreements that cumulatively provide $2.6 billion of credit through December 2027, subject to a 364-day repayment term for Ameren Missouri and Ameren Illinois, with the option to seek incremental commitments to increase the cumulative credit provided to $3.2 billion. See Note 3 – Short-term Debt and Liquidity under Part I, Item 1, of this report and

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Note 4 – Short-term Debt and Liquidity under Part II, Item 8, of the Form 10-K for additional information regarding the Credit Agreements. See Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of the Form 10-K for long-term debt maturities from 2024 to 2028 and beyond at Ameren (parent), Ameren Missouri, Ameren Illinois, and ATXI. See Note 4 – Long-term Debt and Equity Financings under Part I, Item 1, of this report for outstanding forward sale agreements under the ATM and issuances and maturities of long-term debt in 2024 through the date of this report. The use of cash provided by operating activities and short-term borrowings to fund capital expenditures and other long-term investments at the Ameren Companies frequently results in a working capital deficit, defined as current liabilities exceeding current assets, as was the case at June 30, 2024, for Ameren and Ameren Illinois. Ameren, Ameren Missouri, and Ameren Illinois each believe that their liquidity is adequate given their respective expected operating cash flows, capital expenditures, and financing plans, and expect to continue to have access to the capital and credit markets on reasonable terms when needed. However, there can be no assurance that significant changes in economic conditions, disruptions in the capital and credit markets, or other unforeseen events will not materially affect their ability to execute their expected operating, capital, or financing plans.

•Ameren expects its cash used for currently planned capital expenditures and dividends to exceed cash provided by operating activities over the next several years. As part of its funding plan for capital expenditures, Ameren is using newly issued shares of common stock to satisfy requirements under the DRPlus and employee benefit plans and expects to continue to do so through at least 2028. Additionally, Ameren has an ATM program under which Ameren may offer and sell from time to time common stock, which includes the ability to enter into forward sales agreements, subject to market conditions and other factors. As of June 30, 2024, Ameren had multiple forward sale agreements that could be settled under the ATM program with various counterparties relating to 2.9 million shares of common stock. Ameren expects to settle approximately $230 million of the forward sale agreements with physical delivery of 2.9 million shares of common stock by December 31, 2024. Including issuances under the DRPlus and employee benefit plans, Ameren plans to issue approximately $300 million of equity in 2024 and approximately $600 million of equity each year from 2025 to 2028. As of June 30, 2024, Ameren had approximately $770 million of common stock available for sale under the ATM program, which takes into account the forward sale agreements in effect as of June 30, 2024. Ameren expects its equity to total capitalization to support solid investment-grade credit ratings. Ameren Missouri and Ameren Illinois expect to fund cash flow needs through debt issuances, adjustments of dividends to Ameren (parent), and/or capital contributions from Ameren (parent).

•The IRA was enacted in August 2022, and includes various income tax provisions, among other things. The law extends federal production and investment tax credits for projects beginning construction through 2024 and allows for a 10% adder to the production and investment tax credits for siting projects at existing energy communities as defined in the law, which includes sites previously used for coal-fired generation. The law also creates clean energy tax credits for projects placed in service after 2024. The clean energy tax credits will apply to renewable energy production and investments, along with certain nuclear energy production, and will be phased out beginning in 2033, at the earliest. The phase-out is triggered when greenhouse gas emissions from the electric generation industry are reduced by at least 75% from the annual 2022 emission rate or at the beginning of 2033, whichever is later. The law allows for transferability to an unrelated party for cash of up to 100% of certain tax credits generated after 2022. In addition, the new law imposes a 15% minimum tax on adjusted financial statement income, as defined in the law, for corporations whose average annual adjusted financial statement income exceeds $1 billion for three consecutive preceding tax years effective for tax years beginning after December 31, 2022. Once a corporation exceeds this three-year average annual adjusted financial statement income threshold, it will be subject to the minimum tax for all future tax years. Additional regulations, interpretations, amendments, or technical corrections to or in connection with the IRA have been and are expected to be issued by the IRS or United States Department of Treasury, which may impact the timing of when the 15% minimum tax becomes applicable for Ameren as discussed below.

•Pursuant to the IRA discussed above, Ameren expects to transfer production tax credits generated by Ameren Missouri’s High Prairie Renewable and Atchison Renewable energy centers, as well as production or investment tax credits related to the solar facilities included in Ameren Missouri’s 2023 IRP discussed above, to unrelated parties from 2024 to 2028.

•In April 2023, the IRS issued guidance providing a safe harbor method of accounting for the capitalization or deduction of certain expenditures to maintain, repair, replace, or improve natural gas distribution property. The safe harbor method of accounting may be implemented in the first, second, or third taxable year ending after May 1, 2023. Ameren is currently evaluating the potential impact of this guidance, including the timing of adoption.

•As of June 30, 2024, Ameren had $176 million in tax benefits from federal and state income tax credit carryforwards, $46 million in tax benefits from state net operating loss carryforwards, and $19 million in tax overpayments, refunds, and receivables, which will be utilized in future periods. Future expected income tax payments are based on expected taxable income, available income tax credit and net operating loss carryforwards, and current tax law. Expected taxable income is affected by expected capital expenditures, when property, plant, and equipment is placed in-service or retired, and the timing of regulatory reviews, among other things. Based on preliminary calculations, Ameren does not expect to be subject to the 15% minimum tax on adjusted financial statement income imposed by the IRA through 2028. Ameren expects annual federal income tax payments to be immaterial through 2028.

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The above items could have a material impact on our results of operations, financial position, and liquidity. Additionally, in the ordinary course of business, we evaluate strategies to enhance our results of operations, financial position, and liquidity. These strategies may include acquisitions, divestitures, opportunities to reduce costs or increase revenues, and other strategic initiatives to increase Ameren’s shareholder value. We are unable to predict which, if any, of these initiatives will be executed. The execution of these initiatives may have a material impact on our future results of operations, financial position, or liquidity.

REGULATORY MATTERS

See Note 2 – Rate and Regulatory Matters under Part I, Item 1, of this report.

ITEM 3. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK.

There have been no material changes to the quantitative and qualitative disclosures about interest rate risk, credit risk, commodity price risk, investment price risk, and commodity supplier risk included in the Form 10-K, except as discussed below. See Item 7A under Part II of the Form 10-K for a more detailed discussion of our market risk.

ITEM 4. CONTROLS AND PROCEDURES.

(a)Evaluation of Disclosure Controls and Procedures

As of June 30, 2024, evaluations were performed under the supervision and with the participation of management, including the principal executive officer and the principal financial officer of each of the Ameren Companies, of the effectiveness of the design and operation of such registrant’s disclosure controls and procedures (as defined in Rules 13a-15(e) and 15d-15(e) of the Exchange Act). Based on those evaluations, as of June 30, 2024, the principal executive officer and the principal financial officer of each of the Ameren Companies concluded that such disclosure controls and procedures are effective to provide assurance that information required to be disclosed in such registrant’s reports filed or submitted under the Exchange Act is recorded, processed, summarized, and reported within the time periods specified in the SEC’s rules and forms and such information is accumulated and communicated to its management, including its principal executive officer and its principal financial officer, to allow timely decisions regarding required disclosure.

(b)Changes in Internal Controls over Financial Reporting

There has been no change in any of the Ameren Companies’ internal control over financial reporting during their most recent fiscal quarter that has materially affected, or is reasonably likely to materially affect, each of their internal control over financial reporting.

PART II. OTHER INFORMATION

ITEM 1. LEGAL PROCEEDINGS.

We are involved in legal and administrative proceedings before various courts and 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 this report, will not have a material adverse effect on our results of operations, financial position, or liquidity. Risk of loss is mitigated, in some cases, by insurance or contractual or statutory indemnification. We believe that we have established appropriate reserves for potential losses. For additional information on material legal and administrative proceedings, see Note 2 – Rate and Regulatory Matters, Note 9 – Commitments and Contingencies, and Note 10 – Callaway Energy Center, under Part I, Item 1, of this report. Pursuant to Item 103(c)(3)(iii) of Regulation S-K, our policy is to disclose environmental proceedings to which a governmental entity is a party if we reasonably believe such proceedings will result in monetary sanctions of $1 million or more.

ITEM 1A. RISK FACTORS.

The Form 10-K includes a detailed discussion of our risk factors. The information presented below updates, and should be read in conjunction with, the risk factors and information disclosed in Part I, Item 1A, of the Form 10-K.

In connection with the resolution of the NSR and Clean Air Act litigation relating to the Rush Island Energy Center, Ameren and Ameren Missouri could be required to implement additional mitigation relief measures, the costs of which could be material and could adversely impact Ameren and Ameren Missouri's results of operations and financial position.

In January 2011, the United States 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 alleging that projects performed in 2007 and 2010 at the coal-fired Rush Island Energy Center violated provisions of the Clean Air Act and Missouri law. In January 2017, the district court issued a liability ruling against

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Ameren Missouri and, in September 2019, entered a remedy order that required Ameren Missouri to install a flue gas desulfurization system at the Rush Island Energy Center and a dry sorbent injection system at the Labadie Energy Center. Following an appeal from Ameren Missouri, in August 2021, the United States Court of Appeals for the Eighth Circuit affirmed the liability ruling and the district court’s remedy order as it related to the installation of a flue gas desulfurization system at the Rush Island Energy Center, but reversed the order as it related to the installation of a dry sorbent injection system at the Labadie Energy Center. In September 2023, the district court granted Ameren Missouri’s request to modify the remedy order to allow the retirement of the Rush Island Energy Center in advance of its previously expected retirement date of 2039 in lieu of installing a flue gas desulfurization system. In its amended remedy order, the district court established an October 15, 2024 retirement date to allow for the completion of various transmission reliability projects and, in the interim, authorized Ameren Missouri to operate the energy center only as needed and as directed by the MISO. The United States Department of Justice is seeking an order from the district court providing for additional mitigation relief related to prior emissions. Ameren Missouri contends that the retirement of the Rush Island Energy Center, which eliminates all future emissions from the energy center, mitigates claims relating to prior emissions. In March 2024, the district court ordered Ameren Missouri and the United States Department of Justice to file proposed draft orders outlining additional mitigation relief. In May 2024, Ameren Missouri filed a proposed draft order that includes retiring the Rush Island Energy Center, a program to provide electric buses and charging stations to schools in the metro St. Louis area, a program to provide air filters to eligible Ameren Missouri electric residential customers, and the retirement of SO2 allowances. Excluding the accelerated retirement of the Rush Island Energy Center, these programs are estimated to cost approximately $20 million. Also in May 2024, the United States Department of Justice filed a proposed draft order that includes a program to provide electric buses and charging stations to schools in the metro St. Louis area and a program to provide air filters to eligible Ameren Missouri electric residential customers. These programs include a significantly greater number of buses, charging stations, and air filters than Ameren Missouri’s proposal and the United States Department of Justice estimates these programs would cost approximately $120 million. A mediation proceeding related to the potential additional mitigation relief is scheduled for September 2024. As of June 30, 2024, Ameren and Ameren Missouri recorded a $20 million liability related to the cost of potential additional mitigation, which represents the estimated minimum liability, as no other amount within the range was a better estimate. Ameren Missouri could be required to implement some or all of the additional mitigation relief programs included in the United States Department of Justice’s proposed draft order, the costs of which could be material and could adversely impact Ameren and Ameren Missouri’s results of operations and financial position. Depending on the scope and basis of any final order issued by the district court, which is expected by the end of 2024, Ameren Missouri or the United States Department of Justice could appeal any additional mitigation relief ordered.

ITEM 2. UNREGISTERED SALES OF EQUITY SECURITIES AND USE OF PROCEEDS.

Ameren Corporation, Ameren Missouri, and Ameren Illinois did not purchase equity securities reportable under Item 703 of Regulation S-K during the period from April 1, 2024, to June 30, 2024.

ITEM 5. OTHER INFORMATION.

Insider Adoption or Termination of Trading Arrangements

During the fiscal quarter ended June 30, 2024, none of our directors or officers informed us of the adoption or termination of a “Rule 10b5-1 trading arrangement” or “non-Rule 10b5-1 trading arrangement,” as those terms are defined in Regulation S-K, Item 408, except as follows:

On May 21, 2024, Michael L. Moehn, Senior Executive Vice President and Chief Financial Officer of Ameren, adopted a Rule 10b5-1 trading arrangement. Mr. Moehn's Rule 10b5-1 trading arrangement provides for the sale of an aggregate 26,000 shares to be sold in four equal quarterly installments between August 2024 and July 2025. Mr. Moehn’s' Rule 10b5-1 trading arrangement will terminate on the earlier of: (i) July 31, 2025; (ii) execution of all trades or expiration of all orders relating to such trades under the Rule 10b5-1 trading arrangement; or (iii) such date as the Rule 10b5-1 trading arrangement is otherwise terminated according to its terms.

On May 22, 2024, Shawn E. Schukar, Chairman and President of ATXI, adopted a Rule 10b5-1 trading arrangement. Mr. Schukar's Rule 10b5-1 trading arrangement provides for the sale of 100% of any net shares of Ameren common stock received, after tax withholding, in connection with certain previously awarded restricted stock units and performance share units that will vest upon payment in March 2025 and March 2026. The estimated maximum number of shares to be sold pursuant to the Rule 10b5-1 trading arrangement is 10,170 shares. The actual number of shares sold pursuant to the Rule 10b5-1 trading arrangement will depend on the actual number of shares earned pursuant to the awards, which is generally dependent on the Company's achievement of certain performance measures, the actual dividends paid by the Company during the applicable vesting periods, and Mr. Schukar's continued employment and individual performance during the applicable vesting periods. Mr. Schukar's Rule 10b5-1 trading arrangement will terminate on the earlier of: (i) March 31, 2026; (ii) execution of all trades or expiration of all orders relating to such trades under the Rule 10b5-1 trading arrangement; or (iii) such date as the Rule 10b5-1 trading arrangement is otherwise terminated according to its terms.

On June 6, 2024, Mark C. Lindgren, Executive Vice President, Corporate Communications, and Chief Human Resources Officer of Ameren Services Company, adopted a Rule 10b5-1 trading arrangement. Mr. Lindgren's Rule 10b5-1 trading arrangement provides for the

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sale of 50% of any net shares of Ameren common stock received, after tax withholding, in connection with certain previously awarded restricted stock units and performance share units that will vest upon payment in March 2025 and March 2026. The estimated maximum number of shares to be sold pursuant to the Rule 10b5-1 trading arrangement is 3,841 shares. The actual number of shares sold pursuant to the Rule 10b5-1 trading arrangement will depend on the actual number of shares earned pursuant to the awards, which is generally dependent on the Company's achievement of certain performance measures, the actual dividends paid by the Company during the applicable vesting periods, and Mr. Lindgren's continued employment and individual performance during the applicable vesting periods. Mr. Lindgren's Rule 10b5-1 trading arrangement will terminate on the earlier of: (i) March 31, 2026; (ii) execution of all trades or expiration of all orders relating to such trades under the Rule 10b5-1 trading arrangement; or (iii) such date as the Rule 10b5-1 trading arrangement is otherwise terminated according to its terms.

Each of the trading arrangements discussed above is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

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ITEM 6. EXHIBITS.

The documents listed below are being filed or have previously been filed on behalf of the Ameren Companies and are incorporated herein by reference from the documents indicated and made a part hereof. Exhibits not identified as previously filed are filed herewith.

Exhibit Designation	Registrant(s)	Nature of Exhibit	Previously Filed as Exhibit to:
Instruments Defining Rights of Security Holders, Including Indentures
4.1	Ameren Illinois	Supplemental Indenture to the Ameren Illinois Mortgage dated June 1, 2024, for 5.55% First Mortgage Bonds due 2054	June 27, 2024 Form 8-K, Exhibit 4.2, File No. 1-14756
Material Contracts
10.1	Ameren Companies	Separation Agreement and General Release, effective April 5, 2024, between Bhavani Amirthalingam and Ameren Services Company
Rule 13a-14(a) / 15d-14(a) Certifications
31.1	Ameren	Rule 13a-14(a)/15d-14(a) Certification of Principal Executive Officer of Ameren
31.2	Ameren	Rule 13a-14(a)/15d-14(a) Certification of Principal Financial Officer of Ameren
31.3	Ameren Missouri	Rule 13a-14(a)/15d-14(a) Certification of Principal Executive Officer of Ameren Missouri
31.4	Ameren Missouri	Rule 13a-14(a)/15d-14(a) Certification of Principal Financial Officer of Ameren Missouri
31.5	Ameren Illinois	Rule 13a-14(a)/15d-14(a) Certification of Principal Executive Officer of Ameren Illinois
31.6	Ameren Illinois	Rule 13a-14(a)/15d-14(a) Certification of Principal Financial Officer of Ameren Illinois
Section 1350 Certifications
32.1	Ameren	Section 1350 Certification of Principal Executive Officer and Principal Financial Officer of Ameren
32.2	Ameren Missouri	Section 1350 Certification of Principal Executive Officer and Principal Financial Officer of Ameren Missouri
32.3	Ameren Illinois	Section 1350 Certification of Principal Executive Officer and Principal Financial Officer of Ameren Illinois
Interactive Data Files
101.INS	Ameren Companies	Inline XBRL Instance Document - the instance document does not appear in the Interactive Data File because its XBRL tags are embedded within the Inline XBRL document
101.SCH	Ameren Companies	Inline XBRL Taxonomy Extension Schema Document
101.CAL	Ameren Companies	Inline XBRL Taxonomy Extension Calculation Linkbase Document
101.LAB	Ameren Companies	Inline XBRL Taxonomy Extension Label Linkbase Document
101.PRE	Ameren Companies	Inline XBRL Taxonomy Extension Presentation Linkbase Document
101.DEF	Ameren Companies	Inline XBRL Taxonomy Extension Definition Document
104	Ameren Companies	Cover Page Interactive Data File (formatted as Inline XBRL and contained in Exhibit 101)

The file number references for the Ameren Companies’ filings with the SEC are: Ameren Illinois, 1-14756.

Each registrant hereby undertakes to furnish to the SEC upon request a copy of any long-term debt instrument not listed above that such registrant has not filed as an exhibit pursuant to the exemption provided by Item 601(b)(4)(iii)(A) of Regulation S-K.

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SIGNATURES

Pursuant to the requirements of the Exchange Act, each registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized. The signature for each undersigned company shall be deemed to relate only to matters having reference to such company or its subsidiaries.

AMEREN CORPORATION
(Registrant)

/s/ Michael L. Moehn

Michael L. Moehn
Senior Executive Vice President and Chief Financial Officer
(Principal Financial Officer)

UNION ELECTRIC COMPANY
(Registrant)

/s/ Michael L. Moehn

Michael L. Moehn
Senior Executive Vice President and Chief Financial Officer
(Principal Financial Officer)

AMEREN ILLINOIS COMPANY
(Registrant)

/s/ Michael L. Moehn

Michael L. Moehn
Senior Executive Vice President and Chief Financial Officer
(Principal Financial Officer)

Date: August 5, 2024

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EX-10.1

                                    Exhibit 10.1

CONFIDENTIAL SEPARATION AGREEMENT AND GENERAL RELEASE

This Confidential Separation Agreement and General Release (“Agreement”) is entered into by and between Bhavani Amirthalingam (“Employee”) and Ameren Services Company, a Missouri corporation, on behalf of itself and any parent company, subsidiary, division or affiliate entity (collectively, “Ameren”).

RECITALS

A.Employee has been employed by Ameren since March 1, 2018, and most recently Employee has served in the position of Executive Vice President and Chief Customer and Technology Officer.

B.Employee's employment with Ameren (individually, "Party" and collectively, "Parties") is being terminated effective March 22, 2024. On the same date, Employee’s positions and/or responsibilities as an officer of any Ameren entity will also be terminated.

C.In light of Employee’s voluntary resignation, Ameren desires to offer severance benefits to Employee.

D.As a condition for the receipt of severance pay and benefits, the Employee must execute and not revoke a release agreement and must adhere to certain obligations.

NOW, THEREFORE, for good and valuable consideration, the receipt and sufficiency of which is hereby acknowledged, the Parties agree as follows:

1.Separation of Employment. The Parties acknowledge and agree that Employee’s employment with Ameren will terminate effective March 22, 2024 (“Separation Date”), thereby terminating as of that date all further obligations of Ameren to Employee, of whatever kind and nature, including all forms of compensation and benefits that otherwise might have been owed to Employee due to Employee’s holding any employment or other position with Ameren, except those that are expressly identified in this Agreement. To the extent necessary, Employee agrees to (i) take any further appropriate actions to resign from any position which Employee holds at Ameren, and (ii) execute any paperwork or comply with any procedures reasonably necessary to effectuate this separation.

Employee acknowledges that except as provided in Paragraph 2 below and any vested benefits to which Employee is entitled under an employee benefit plan (as defined below), Employee is not entitled to any payments or benefits under any employee benefit plan of Ameren, including, without limitation, the Ameren Corporation Severance Plan, any Ameren Short Term Incentive Plan for Employee Directors, the 2022 Omnibus Incentive Compensation Plan, and the Long-Term Incentive Program (collectively, the “Plans”), following Employee’s termination of employment. Ameren agrees that by execution of this Agreement, Employee does not forfeit or waive any long term savings plan (401(k)), ESOP or pension benefits which have vested to the Employee as of the effective date of the Employee’s separation.

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“Employee benefit plan” means each deferred compensation and each incentive compensation, stock purchase, stock option and other equity compensation plan, program, agreement or arrangement; each severance or termination pay, medical, surgical, hospitalization, life insurance and other “welfare” plan, fund or program (within the meaning of Section 3(1) of Title I of the Employee Retirement Income Security Act of 1974 (“ERISA”); each profit-sharing, stock bonus or other “pension” plan, fund or program (within the meaning of Section 3(2) of Title I of ERISA); each employment, termination or severance agreement; and each other employee benefit plan, fund, program, agreement or arrangement, in each case, that is sponsored, maintained or contributed to or required to be contributed to by Ameren, or to which Ameren is a party, whether written or oral, for the benefit of Employee.

2.Separation Benefits; Final Pay.

a.Severance Payment. Employee shall be paid a lump sum severance payment (“Severance Payment”) in the amount of One Million One Hundred Twelve Thousand Eight Hundred Seventy-Five Dollars and No Cents ($1,112,875.00), representing one times Employee’s annual base salary plus an amount equal to Employee’s short-term incentive target plus a pro rata 2024 short-term incentive award. The Severance Payment will be paid as soon as administratively practicable following the expiration of the revocation period described in Paragraph 15 below, provided no revocation has occurred. The amount of the Severance Payment shall be reduced by federal, state and local taxes and withholdings required by law. The Severance Payment is not eligible earnings for pension or 401(k) purposes. In the event of a revocation of this Agreement by Employee, Ameren shall not be obligated to make the above Severance Payment or to provide any other benefits identified in this Agreement and this Agreement shall be null and void.

b.Medical Coverage. Employee may elect to continue health insurance coverage under the Ameren Group Medical Plan pursuant to the Consolidated Omnibus Budget Reconciliation Act (“COBRA”), for a maximum period not to exceed eighteen (18) months, unless otherwise required by law. If elected, Ameren will provide a COBRA subsidy benefit for up to the first twelve (12) months of COBRA coverage equal to 100% of the applicable COBRA coverage. Thereafter, COBRA coverage will be provided at applicable premium rates. Ameren will provide Employee with a COBRA notice and election form and Employee understands that Employee must enroll for COBRA coverage and pay applicable premiums in order to receive COBRA benefits. However, if Employee is eligible to participate in the Ameren Retiree Medical Plan, but elects to continue coverage under the Ameren Group Medical Plan pursuant to COBRA, the Employee will be precluded from electing retiree medical coverage under the Ameren Retiree Medical Plan in the future. For additional benefits offered see the Plan. Nothing in this Agreement shall prevent Ameren from increasing or decreasing contribution rates for its medical programs, or from amending, modifying or terminating its active employee or medical programs, as such rights are reserved to Ameren under the terms of such programs.

c.Final Salary and Vacation. Employee’s final paycheck will include payment for any earned but unpaid salary and vacation pay consistent with the provisions of the Management Vacation Policy, reduced by federal, state and local taxes and withholdings required by law.

d.Career Transition Services. Ameren will provide Employee with executive level transition services through Human Resource Management Corporation for a period of 12

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months following the Separation Date or, if earlier, through the date Employee obtains other employment. Employee agrees to promptly notify Ameren if she obtains alternate employment during this 12 month period. If Employee does not use these services, Employee will not be provided the cash equivalent.

The payments and benefits referred to in this Paragraph 2 and Exhibit A shall discharge all obligations of Ameren to Employee for wages, damages of any kind, benefits, bonuses, vacation pay, sick pay, severance pay, costs, or any other expectation of remuneration or benefit on the part of Employee. By signing this Agreement, Employee acknowledges and agrees that Employee is waiving any right or claim Employee may have to benefits, compensation, restricted stock awards, performance share unit awards, or payment under any Ameren bonus, incentive compensation and/or separation plan, with the exception of the payments specifically identified in this Agreement. The payments and benefits referred to in this Paragraph 2 and Exhibit A relate exclusively to the Employee’s service as an employee of Ameren. Employee acknowledges that said payments constitute good and valuable consideration for the various commitments undertaken and releases provided by Employee in this Agreement. Employee further acknowledges that the totality of the consideration and benefits provided by Ameren pursuant to this Agreement are above and beyond those to which Employee is otherwise entitled.

3.Waiver of Future Employment with Ameren. By signing this Agreement, Employee now and forever waives reinstatement to employment with Ameren as a regular or temporary employee. Employee further agrees that Employee will not, any time in the future, seek employment or attempt to make an application for employment with Ameren without the written permission of Mark Lindgren, Chief Human Resources Officer, or his successor. Employee acknowledges and agrees that Employee’s forbearance from seeking future employment is purely contractual and is in no way involuntary, discriminatory, or unlawful. A breach of this provision by Employee will constitute lawful and just cause to refuse to employ Employee or to terminate Employee if already employed.

4.Waiver and Release. In consideration for the payments and benefits referred to in Paragraph 2, Employee on behalf of herself and her spouse, family and heirs, executors, administrators, attorneys, agents and assigns, hereby waive, release and forever discharge Ameren and all of its past and present affiliates, parents, subsidiaries and divisions, whether direct or indirect, its and their joint ventures and joint venturers (including its and their respective directors, officers, associates, employees, shareholders, partners, agents and employee benefit plans and the trustees, fiduciaries and administrators of those plans, past, present and future), and each of its and their respective predecessors, successors, heirs, representatives, executors, administrators and assigns (collectively referred to as “Releasees”), from ANY and ALL known or unknown actions, causes of action, claims or liabilities of any kind that have or could be asserted against Releasees arising out of or related to Employee’s employment with and/or separation from employment with Releasees and/or any other occurrence up to and including the day Employee signs this Agreement, including but not limited to:

a.claims, actions, causes of action or liabilities arising under Title VII of the Civil Rights Act, as amended, the Family and Medical Leave Act, the Age Discrimination in Employment Act, as amended (the “ADEA”), the Employee Retirement Income Security Act, as amended, the Rehabilitation Act, as amended, the Americans with Disabilities Act, as amended,

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the National Labor Relations Act, the Worker Adjustment and Retraining Notification Act, the Sarbanes-Oxley Act, the Dodd-Frank Consumer Protection and Wall Street Reform Act, the False Claims Act, and/or any other federal, state, municipal or local employment discrimination statutes, laws, regulations, ordinances or executive orders (including, but not limited to, claims based on age, sex, attainment of benefit plan rights or entitlement to benefits, race, color, religion, natural origin, source of income, union activities, marital status, sexual orientation, ancestry, harassment, parental status, disability, retaliation and veteran status); and/or

b.with respect to unknown claims, Employee expressly acknowledges that this Waiver and Release in this Agreement is intended to include, without limitation, claims that Employee did not know or suspect to exist in Employee’s favor at the time Employee signs this Agreement, regardless of whether the Employee’s knowledge of such claims, or the facts upon which they might be based would materially have affected the settlement with Releasees herein; and/or

c.any other claim whatsoever including, but not limited to, claims for severance pay (other than claims for severance pay and severance benefits under this Agreement), disputed claims for salary/wages/commissions/bonuses, claims based upon breach of contract, wrongful termination, defamation, intentional infliction of emotional distress, tort, personal injury, invasion of privacy, violation of public policy, violation of Releasees’ personnel policies, negligence and/or any other common law, statutory or other claim whatsoever arising out of or relating to Employee’s employment with and/or separation from employment with Releasees to the maximum extent permitted by law.

5.Exclusions from General Release/Additional Employee Protections. Excluded from the Waiver and Release in Paragraph 4 above are any claims or rights which cannot be waived by law, including any right to accrued vacation, workers compensation benefits (although Employee represents that Employee has reported any work-related injuries that Employee suffered or sustained during Employee’s employment with Releasees), or unemployment insurance benefits. Neither the Waiver and Release above nor anything else in this Agreement limits Employee’s rights to file a charge with an administrative agency (such as the U.S. Equal Employment Opportunity Commission), provide information to or communicate directly with any federal, state or local agency, or participate in any agency investigation or other administrative proceeding. However, by signing this Agreement, Employee waives Employee’s right to recover money or other individual relief in connection with any such charge or investigation, except as provided in Paragraph 16. Notwithstanding any other provision in this Agreement, Employee understands that nothing in this Agreement precludes Employee from communicating, nor impairs or restricts in any way his ability to communicate, with the Nuclear Regulatory Commission (NRC), the Department of Labor, or any other Federal or State government agency, or representatives thereof, concerning any potential violations or other matters within the NRC’s, the DOL’s, or other government agency's regulatory responsibilities, or from testifying in any NRC proceeding, or before Congress, or at any Federal or State proceeding regarding any provision or proposed provision of the Atomic Entergy Act or the Energy Reorganization Act. Employee agrees to cooperate fully in any investigation conducted by the NRC, Ameren, or any state or governmental agency relating to the matters occurring during Employee’s employment at Ameren.

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6.Current Claims. Employee represents that Employee has disclosed any currently pending claim of unlawful discrimination, harassment, sexual harassment, abuse, assault, or other criminal conduct, or retaliation against Ameren or any Releasees.

7.Covenant Not To Sue. In addition to and apart from the Waiver and Release contained in Paragraph 4, Employee also agrees never to sue Releasees or become party to a lawsuit on the basis of any claim of any type whatsoever arising out of or related to her employment with and/or retirement from Ameren, other than legal action (i) to challenge this Agreement under the ADEA, or (ii) to enforce the payment of the pay and/or benefits under this Agreement.

8.Consequences Of Breach Of Covenant Not To Sue. Employee further acknowledges and agrees that if Employee breaches the provisions of Paragraph 4 above, then Employee shall be obligated to pay to Releasees its costs and expenses in enforcing this Agreement and defending against such lawsuit (including court costs, expenses and reasonable legal fees). Alternatively, at Releasees’ option: (a) Releasees shall be entitled to apply for and receive an injunction to restrain any violation of Paragraph 4 above and (b) Employee shall be obligated upon demand to repay to Releasees all but $1,000.00 of the payments and benefits paid or made available to Employee under Paragraph 2 of this Agreement. Employee further agrees that the foregoing covenants in this Paragraph shall not affect the validity of this Agreement and shall not be deemed to be a penalty nor a forfeiture.

9.Ownership of Claims. Employee represents that Employee has not transferred or assigned, or purported to transfer or assign, to any person or entity, any claim described in this Agreement. Employee further agrees to indemnify and hold harmless Releasees against any and all claims based upon, arising out of, or in any way connected with any such actual or purported transfer or assignment.

10.Protected Rights. Nothing in this Release, including but not limited to the full and final release of claims, promise not to sue, representations, return of company property, confidential information, no disparagement, cooperation, and confidentiality of agreement provisions: (i) limits or affects Employee’s right to challenge the validity of this Release under the ADEA or the OWBPA, (ii) limits the rights of any governmental agency or prevents Employee from communicating with, filing a charge or complaint with, cooperating with, or otherwise participating in an investigation or proceeding conducted by the Equal Employment Opportunity Commission, National Labor Relations Board, the Securities and Exchange Commission, the Department of Justice, and/or any other any federal, state or local agency charged with the enforcement of any laws, including providing documents or any other information, or (iii) limits Employee from exercising rights under Section 7 of the NLRA to engage in protected, concerted activity with other employees. By signing this Release, Employee is waiving rights to individual relief (including back pay, front pay, reinstatement or other legal or equitable relief) in any proceeding brought by Employee or on Employee’s behalf by any third party, to the extent permitted by law, except for any right Employee may have to receive a payment or award from a government agency for information provided to the government agency or otherwise where prohibited.

11.Employee Acknowledgements. Employee further agrees that Employee (i) is not signing this Agreement before the Separation Date (the last day of employment with Ameren), (ii) has been paid for all hours worked, including overtime; and (iii) is not aware of any job

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injury for which Employee has not already filed a claim. Employee represents that Employee has not filed any lawsuit against any Releasee with any local, state, or federal or court.

12.General Release. The Parties hereby acknowledge and agree that the release set forth in Paragraph 4 above is a general release of all known and unknown claims that Employee holds or previously held against Releasees, or any of them, whether or not they are specifically referred to herein and is intended to be enforced to the maximum extent permitted by law. No reference herein to any specific claim, statute or obligation is intended to limit the scope of this general release and, notwithstanding any such reference, this Agreement shall be effective as a full and final bar to all claims that are released in this Agreement. Notwithstanding the generality of this provision, this release does not include any claim for benefits by Employee under any state Workers’ Compensation Act.

13.Non-Admission. The Parties understand and agree that this Agreement is intended to finally and fully conclude the employment relationship between Employee and Ameren, and shall not be interpreted as an admission by the Parties or Releasees of any wrongdoing or any violation of federal, state or local law, regulation or ordinance. The Parties expressly deny that they, or their employees, supervisors, representatives, agents, officers, or directors, have committed any wrongdoing whatsoever.

14.Taxes. Employee agrees that Employee is responsible for the payment of all federal, state and local taxes, of any type whatsoever, due and resulting from the payment to Employee of any consideration identified in this Agreement.

15.Attorney Review; Time for Execution; Revocation; Acknowledgements. Ameren hereby advises Employee to consult with an attorney prior to signing this Agreement. Each Party shall bear all attorneys’ fees and costs arising from the actions of its own counsel in connection with the review and execution of this Agreement. Employee shall have twenty-one (21) days from the date of the presentation of this Agreement to consider whether to sign it. Employee may revoke the Agreement, thereby nullifying the Agreement and all of its terms, by notifying Ameren through written notice of revocation by U.S. Mail or hand delivery to Mark Lindgren, Chief Human Resources Officer, 1901 Chouteau Avenue, St. Louis, Missouri 63103, Ameren’s designated agent for this purpose, at any time within seven (7) days after signing the Agreement. In the event Employee exercises Employee’s right to revoke this Agreement or the Agreement is not signed and returned within 21 days after the date of the presentation of this Agreement, this Agreement will be null and void and Ameren shall have no obligation to make the payments or furnish the other consideration recited above, or any other obligation under this Agreement. If Employee does not revoke this Agreement, the Agreement shall be effective and fully enforceable on the eighth (8th) calendar day after Employee signs it (the “Effective Date”).

Among the claims being waived and released by Employee are any and all claims under the federal Age Discrimination in Employment Act (“ADEA”) and the Older Workers Benefit Protection Act of 1990 (“OWBPA”). Pursuant to the requirements of the ADEA and OWBPA, Employee expressly agrees, acknowledges and understands that:

(a)other than what is required by law, the consideration set forth in Paragraph 2 above is consideration that Employee is not otherwise entitled to and is given in exchange for

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the release contained in Paragraph 4 above and for the other promises contained in this Agreement;

(b)Employee is waiving any and all rights or claims arising under the Age Discrimination in Employment Act;

(c)Employee has been, and is hereby, advised by Ameren to consult with an attorney prior to signing this Agreement;

(d)Employee has been given a period of at least twenty-one (21) days within which to consider this Agreement;

(e)this Agreement does not become effective or enforceable until the seven (7)-day revocation period described above has elapsed, with no revocation having occurred;

(f)Employee may revoke this Agreement at any time within seven (7) days after signing it;

(g)Employee shall not be entitled to any payments or benefits under this Agreement in the event of a revocation;

(h)Employee has had a full opportunity to read and consider this Agreement and has relied on Employee’s own judgment and/or that of Employee’s attorney regarding the consideration for and the terms of this Agreement;

(i)No statements or conduct by any Releasee has in any way coerced or unduly influenced Employee to execute this Agreement; and

(i)Employee has knowingly and voluntarily entered into this Agreement, and fully understands and agrees to all of its terms.

16.Confidential Information.

a.Employee, by virtue of Employee’s position with Ameren, had access to and/or received trade secrets and other confidential and proprietary information about Ameren’s business that is not generally available to the public and which has been developed or acquired by Ameren at considerable effort and expense (hereinafter “Confidential Information”). Confidential Information includes, but is not limited to, information about Ameren’s business plans and strategy, environmental strategy, legal strategy, legislative strategy, finances, marketing, management, operations, trade secrets, data, processes, inventions and ideas, and/or personnel. Employee agrees that Employee will hold the Confidential Information in strictest confidence and take reasonable efforts to protect such Confidential Information from disclosure to any third party who is not authorized to receive, review or access the Confidential Information. Employee also agrees to not use Confidential Information on behalf of Employee or any third party and, by signing this Agreement, affirms that Employee has returned all Confidential Information to Ameren and, as such, does not possess or have access to Ameren Confidential Information. The foregoing obligation shall continue to exist for so long as such information remains Confidential Information; provided, however, nothing in this Agreement prohibits or limits Employee from (i) reporting possible violations of federal securities law or

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regulation to any governmental agency or entity or receiving a monetary award from the governmental agency or entity for the information reported.

b.Notwithstanding the foregoing, in accordance with the Defend Trade Secrets Act of 2016, Employee will not be held criminally or civilly liable under any federal or state trade secret law for the disclosure of a trade secret that: (i) is made (A) in confidence to a

federal, state, or local government official, either directly or indirectly, or to an attorney; and (B) solely for the purpose of reporting or investigating a suspected violation of law; or (ii) is made in a complaint or other document that is filed under seal in a lawsuit or other proceeding. If Employee files a lawsuit for retaliation by Ameren for reporting a suspected violation of law, Employee may disclose Ameren’s trade secrets to his or her attorney and use the trade secret information in the court proceeding if Employee (i) files any document containing the trade secret under seal; and (ii) does not disclose the trade secret, except pursuant to court order.

17.Confidentiality of Agreement. Employee agrees not to divulge or release this Agreement or its contents, except to Employee’s attorneys, financial advisors, or spouses or domestic partners, provided they agree to keep this Agreement and its contents confidential, or as required or permitted by law. Nothing in this paragraph shall require confidentiality of any claims of sexual harassment or abuse. In the event Employee receives a subpoena or court order requiring the release of this Agreement or its contents or any Confidential Information, Employee will notify Ameren Services Company’s Legal Department sufficiently in advance of the date for the disclosure of such information in order to enable Ameren to contest the subpoena or court order, and Employee agrees to cooperate with Ameren in any related proceeding involving the release of this Agreement or its contents or any Confidential Information. If Employee is asked why her employment with Ameren ended, she may state that she resigned.

18.Non-Disparagement. Employee agrees that Employee will not make any public statement that would adversely affect the business of Ameren or Releasees in any manner, at any time, even beyond the date after which Employee will receive no further compensation or benefits pursuant to this Agreement. Employee agrees that Employee will not disparage, criticize or speak negatively about Releasees or their decisions or actions, about Releasees’ products, services or operations, about any of Releasees’ past, present or future directors, officers or employees or any of their actions or decisions, or about Releasees’ customers. Nothing in this Paragraph shall prohibit Employee from providing testimony pursuant to a subpoena or court order. Ameren agrees it will instruct members of its Executive Leadership Team not to disparage Employee.

19.Non-Solicitation. For a period of twelve (12) months following Employer’s execution of this Agreement, Employee will not directly or indirectly, on behalf of Employee or any other person, company or entity:

a.market, sell, solicit, or provide products or services competitive with or similar to products or services offered by Ameren to any person, company or entity that: (i) is a customer or potential customer of Ameren during the twelve (12) months prior to Employee’s execution of this Agreement and (ii) with whom Employee (a) had direct contact with during the twelve (12) months prior to Employee’s execution of this Agreement or (b) possessed, utilized or developed Confidential Information about during the twelve (12) months prior to Employee’s execution of this Agreement;

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b.raid, solicit, encourage or attempt to persuade any employee or independent contractor of Ameren, or any person who was an employee or independent contractor of Ameren during the 24 months preceding Employee’s execution of this Agreement, to leave the employ of, terminate or reduce the person’s employment or business relationship with, Ameren;

c.interfere with the performance of any Ameren employee or independent contractor’s duties for Ameren.

20.Remedies. The Parties respectively acknowledge that the other Party would be greatly injured by, and have no adequate remedy at law for, breach of obligations contained in Paragraphs 16-19 above. Employee further acknowledges and agrees that the Confidentiality and Non-Solicitation provisions set forth in Paragraphs 16 and 19 are necessary to protect Ameren’s legitimate business interests, such as its Confidential Information, goodwill and customer relationships. Employee therefore acknowledges and agrees that in the event of a breach or threatened breach of Paragraphs 16, 17, 18 and/or 19, Ameren shall be entitled as a matter of right (without being required to prove damages or furnish any bond or other security) to obtain a restraining order, an injunction, or other equitable or extraordinary relief that restrains any further violation or threatened violation of Paragraph 16, 17, 18 and/or 19, as well as an order requiring Employee to comply with Paragraph 16, 17, 18 and/or 19. Ameren’s right to a restraining order, an injunction, or other equitable or extraordinary relief shall be in addition to all other rights and remedies to which Ameren may be entitled to in law or in equity, including, without limitation, the right to recover monetary damages for Employee’s violation or threatened violation of Paragraph 16, 17, 18 and/or 19. Finally, Ameren shall be entitled to an award of attorneys’ fees incurred in connection with securing any relief hereunder and/or pursuant to a breach or threatened breach of Paragraph 16, 17, 18 and/or 19.

In addition, if Employee materially violates the Confidentiality and Non-Solicitation obligations described in Paragraphs 16 and 19, or engages in conduct or activity that is materially detrimental to Ameren in the one year after Employee’s execution of this Agreement, then Employee shall repay the Severance Payment to Ameren within thirty (30) days of receiving a demand from Ameren for repayment.

21.Employment Verification. In keeping with Ameren policies and procedures, Employee should direct all requests for employment verification to Ameren’s third-party employment verification vendor (“work verification vendor”). The work verification vendor will provide only the dates of Employee’s employment and positions held. Any inquiries for employment verification or references that come to Ameren will be directed to the work verification vendor. Employee understands that Ameren will not provide additional information regarding Employee’s employment unless compelled to do so by law. Mark Lindgren will provide Employee with instructions for submitting inquiries to the work verification vendor.

22.Cooperation. Employee agrees to cooperate with Ameren regarding any pending or subsequently filed internal investigations, litigation, claims, or other disputes or legal proceedings involving Ameren that relate to matters within the knowledge or responsibility of Employee during employment with Ameren. Without limiting the foregoing, Employee agrees: (i) to meet with Ameren’s representatives, its counsel, or other designees at reasonable times and

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places; (ii) to provide truthful testimony regarding same to any court, agency, or other adjudicatory or investigative body; and (iii) to provide Ameren with notice of contact by any adverse party or such adverse party’s representative except as may be required by law. Ameren will reimburse Employee for Employee’s time at a reasonable hourly rate and other reasonable expenses in connection with the cooperation described in this paragraph.

23.Severability. The provisions of this Agreement are fully severable. Therefore, if any provision of this Agreement is for any reason determined to be invalid or unenforceable by a Court of competent jurisdiction, such invalidity or unenforceability will not affect the validity or enforceability of any of the remaining provisions. Furthermore, any invalid or unenforceable provisions shall be modified or restricted to the extent and in the manner necessary to render the same valid and enforceable, or, if such provision cannot under any circumstances be modified or restricted, it shall be excised from the Agreement without affecting the validity or enforceability of any of the remaining provisions.

24.Entire Agreement; Amendment and Waiver. This Agreement constitutes the entire agreement between the Parties with respect to the subject matters of this Agreement and supersedes all prior negotiations and agreements, whether written or oral. The provisions of this Agreement may not be altered, amended or waived except by a written document signed by both Parties. Employee represents and acknowledges that in signing this Agreement Employee has not relied upon any representation or statement not set forth herein made by Ameren or any of the Releasees or by any of their agents, representatives or attorneys, with regard to the subject matters, basis or effect of this Agreement, Ameren, its business or its stock, or any other matter.

25.Arbitration. Other than disputes pertaining to the Plans or the provisions of Paragraphs 16, 17, 18 or 19 above, any other dispute regarding any aspect of this Agreement or any act which allegedly has or would violate any provision of this Agreement (“Arbitrable Claim”) will be exclusively submitted to arbitration before a neutral arbitrator. If the Parties are unable to agree upon a neutral arbitrator, the Parties will obtain a list of five arbitrators from the American Arbitration Association. Employee, first, and then Ameren will alternately strike names from the list until only one name remains; the remaining person shall be the arbitrator. Arbitration of Arbitrable Claims shall be in accordance with the Employment Arbitration Rules of the American Arbitration Association. Arbitration proceedings shall be held in such location as mutually agreed upon by the Parties. The arbitrator shall determine the prevailing party in the arbitration. The arbitrator shall be permitted to award only those remedies otherwise available in law or equity which are requested by the Parties, are appropriate for the claims, and are supported by credible, relevant evidence. Employee and Ameren agree that this arbitration shall be the exclusive means of resolving any Arbitrable Claim and that no other action will be brought by the Parties in any court or other forum. Notwithstanding the above, any Party may bring an action in court to compel arbitration under this Agreement and to enforce an arbitration award. The Federal Arbitration Act shall govern the interpretation and enforcement of this Paragraph.

Initialed by Bhavani Amirthalingam /s/ AB

11 of 11

26.Successors and Assigns. This Agreement shall be binding upon, and shall inure to the benefit of, Employee and Employee’s personal and legal representatives, heirs, devisees, executors, successors, and assigns, and Ameren and its successors and assigns.

27.Paragraph Headings; Governing Law; Third Party Benefit. Paragraph headings herein are for convenience and reference only and in no way define, limit or enlarge the rights and obligations of the Parties under this Agreement. This Agreement and any amendments to this Agreement shall be construed and interpreted in accordance with the laws of the State of Missouri, without regard to conflicts of law principles. With respect to any dispute concerning Paragraphs 16, 17, 18, or 19 the Parties agree that the dispute shall be brought in either the state or Federal court located in St. Louis, Missouri, and Employee agrees to submit himself/herself to the jurisdiction of the state or Federal court located in St. Louis, Missouri without regard to conflicts of law principles or personal jurisdiction. The provisions of this Agreement are intended to benefit each of the Releasees and as such may be enforced by each of the Releasees in its individual right.

28.Amendment. This Agreement may be amended only in a writing signed by both

parties.

29.Waiver. The waiver by Ameren of a breach of any provision of this Agreement

by Employee shall not operate or be construed as a waiver of any subsequent breach by Employee. The waiver by Employee of a breach of any provision of this Agreement by Ameren shall not operate or be construed as a waiver of any subsequent breach by Ameren.

IN WITNESS WHEREOF, the undersigned have signed this Separation Agreement and General Release on the date(s) identified below.

PLEASE READ CAREFULLY. THIS SEPARATION AGREEMENT AND GENERAL RELEASE INCLUDES A RELEASE OF ALL CLAIMS. BY SIGNING BELOW, THE PARTIES ACKNOWLEDGE AND AGREE THAT THEY HAVE CAREFULLY READ AND FULLY UNDERSTAND THIS AGREEMENT AND UNDERSTAND THE RIGHTS THEY ARE WAIVING BY SIGNING THIS AGREEMENT. THE PARTIES ARE ENTERING INTO THIS AGREEMENT KNOWINGLY AND VOLUNTARILY, AND SIGN IT OF THEIR OWN FREE ACT AND DEED.

Ameren Services Company                EMPLOYEE:

/s/ Mark. C. Lindgren                /s/ Bhavani Amirthalingam

Mark Lindgren, EVP, Corporate            Bhavani Amirthalingam

Communications & Chief Human Resources

Officer

Date:    Apr 5, 2024                Date: Apr 5, 2024

Exhibit A-1

Benefit Summary Contingent Upon Executing

Separation Agreement and General Release

Bhavani Amirthalingam

March 2024

1.Severance Payment

One Million One Hundred Twelve Thousand Eight Hundred Seventy-Five Dollars and 00/100 ($1,112,875.00)

The amount of the Severance Payment, reduced by federal, state and local taxes and withholdings required by law and payable as described in the Separation Agreement and General Release. Severance Payment is not eligible earnings for pension or 401(k) purposes. In the event of a revocation of this Agreement by Employee, Ameren shall not be obligated to make the above Severance Payment or to provide any other benefits identified in this Agreement.

2. Career Transition Services

Ameren will provide Employee with executive level career transition services through Human Resource Management Corporation for a period not to exceed the earlier of twelve (12) months or through the date Employee obtains other employment. You are not entitled to cash in lieu of these services.

3.Medical Coverage

Employee may elect to continue health insurance coverage under the Ameren Group Medical Plan

pursuant to the Consolidated Omnibus Budget Reconciliation Act (“COBRA”), for a maximum period not

to exceed eighteen (18) months, unless otherwise required by law. If elected, Ameren will provide a

COBRA subsidy benefit for up to the first twelve (12) months of COBRA coverage equal to 100% of the

applicable COBRA coverage. Thereafter, COBRA coverage will be provided at applicable premium rates.

This page A-1 summarizes the benefits you could receive at separation subject to your executing, without revocation, the valid Confidential Separation Agreement and General Release. For specific information about your benefits, please go to myAmeren.com or call the myAmeren Benefits Center at 1.877.769.2637. Actual benefit amounts are subject to change and will be updated to the actual and applicable payment date.

EX-31.1

Exhibit 31.1

RULE 13a-14(a)/15d-14(a) CERTIFICATION

OF PRINCIPAL EXECUTIVE OFFICER OF AMEREN CORPORATION

(required by Section 302 of the Sarbanes-Oxley Act of 2002)

    I, Martin J. Lyons, Jr., certify that:

    1.    I have reviewed this report on Form 10-Q for the quarterly period ended June 30, 2024 of Ameren Corporation;

    2.    Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

    3.    Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

    4.    The registrant’s other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

a)Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b)Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, 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;

c)Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

d)Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

    5.    The registrant’s other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

a)All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

b)Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Date: August 5, 2024

 /s/ Martin J. Lyons, Jr.

Martin J. Lyons, Jr.
Chairman, President and Chief Executive Officer
(Principal Executive Officer)

EX-31.2

Exhibit 31.2

RULE 13a-14(a)/15d-14(a) CERTIFICATION

OF PRINCIPAL FINANCIAL OFFICER OF AMEREN CORPORATION

(required by Section 302 of the Sarbanes-Oxley Act of 2002)

    I, Michael L. Moehn, certify that:

    1.    I have reviewed this report on Form 10-Q for the quarterly period ended June 30, 2024 of Ameren Corporation;

    2.    Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

    3.    Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

    4.    The registrant’s other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

a)Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b)Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, 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;

c)Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

d)Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

    5.    The registrant’s other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

a)All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

b)Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Date: August 5, 2024

 /s/ Michael L. Moehn

Michael L. Moehn
Senior Executive Vice President and Chief Financial Officer
(Principal Financial Officer)

EX-31.3

Exhibit 31.3

RULE 13a-14(a)/15d-14(a) CERTIFICATION

OF PRINCIPAL EXECUTIVE OFFICER OF UNION ELECTRIC COMPANY

(required by Section 302 of the Sarbanes-Oxley Act of 2002)

    I, Mark C. Birk, certify that:

    1.    I have reviewed this report on Form 10-Q for the quarterly period ended June 30, 2024 of Union Electric Company;

    2.    Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

    3.    Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

    4.    The registrant’s other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

a)Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b)Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, 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;

c)Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

d)Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

    5.    The registrant’s other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

a)All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

b)Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Date: August 5, 2024

 /s/ Mark C. Birk

Mark C. Birk
Chairman and President
(Principal Executive Officer)

EX-31.4

Exhibit 31.4

RULE 13a-14(a)/15d-14(a) CERTIFICATION

OF PRINCIPAL FINANCIAL OFFICER OF UNION ELECTRIC COMPANY

(required by Section 302 of the Sarbanes-Oxley Act of 2002)

    I, Michael L. Moehn, certify that:

    1.    I have reviewed this report on Form 10-Q for the quarterly period ended June 30, 2024 of Union Electric Company;

    2.    Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

    3.    Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

    4.    The registrant’s other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

a)Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b)Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, 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;

c)Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

d)Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

    5.    The registrant’s other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

a)All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

b)Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Date: August 5, 2024

 /s/ Michael L. Moehn

Michael L. Moehn
Senior Executive Vice President and Chief Financial Officer
(Principal Financial Officer)

EX-31.5

Exhibit 31.5

RULE 13a-14(a)/15d-14(a) CERTIFICATION

OF PRINCIPAL EXECUTIVE OFFICER OF AMEREN ILLINOIS COMPANY

(required by Section 302 of the Sarbanes-Oxley Act of 2002)

    I, Leonard P. Singh, certify that:

    1.    I have reviewed this report on Form 10-Q for the quarterly period ended June 30, 2024 of Ameren Illinois Company;

    2.    Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

    3.    Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

    4.    The registrant’s other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

a)Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b)Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, 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;

c)Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

d)Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

    5.    The registrant’s other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

a)All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

b)Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Date: August 5, 2024

 /s/ Leonard P. Singh

Leonard P. Singh
Chairman and President
(Principal Executive Officer)

EX-31.6

Exhibit 31.6

RULE 13a-14(a)/15d-14(a) CERTIFICATION

OF PRINCIPAL FINANCIAL OFFICER OF AMEREN ILLINOIS COMPANY

(required by Section 302 of the Sarbanes-Oxley Act of 2002)

    I, Michael L. Moehn, certify that:

    1.    I have reviewed this report on Form 10-Q for the quarterly period ended June 30, 2024 of Ameren Illinois Company;

    2.    Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

    3.    Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

    4.    The registrant’s other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

a)Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b)Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, 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;

c)Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

d)Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

    5.    The registrant’s other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

a)All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

b)Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Date: August 5, 2024

 /s/ Michael L. Moehn

Michael L. Moehn
Senior Executive Vice President and Chief Financial Officer
(Principal Financial Officer)

EX-32.1

Exhibit 32.1

SECTION 1350 CERTIFICATION OF THE PRINCIPAL EXECUTIVE OFFICER

AND THE PRINCIPAL FINANCIAL OFFICER OF

AMEREN CORPORATION

(required by Section 906 of the Sarbanes-Oxley Act of 2002)

In connection with the report on Form 10-Q for the quarterly period ended June 30, 2024 of Ameren Corporation (the “Registrant”) as filed by the Registrant with the Securities and Exchange Commission on the date hereof (the "Form 10-Q”), each undersigned officer of the Registrant does hereby certify, pursuant to 18 U.S.C. §1350, as adopted pursuant to §906 of the Sarbanes-Oxley Act of 2002, that:

(1)The Form 10-Q fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934 (15 U.S.C. 78m or 78o(d)); and

(2)The information contained in the Form 10-Q fairly presents, in all material respects, the financial condition and results of operations of the Registrant.

Date: August 5, 2024

 
 /s/ Martin J. Lyons, Jr.

Martin J. Lyons, Jr.
Chairman, President and Chief Executive Officer
(Principal Executive Officer)

 /s/ Michael L. Moehn

Michael L. Moehn
Senior Executive Vice President and Chief Financial Officer
(Principal Financial Officer)

EX-32.2

Exhibit 32.2

SECTION 1350 CERTIFICATION OF THE PRINCIPAL EXECUTIVE OFFICER

AND THE PRINCIPAL FINANCIAL OFFICER OF

UNION ELECTRIC COMPANY

(required by Section 906 of the Sarbanes-Oxley Act of 2002)

In connection with the report on Form 10-Q for the quarterly period ended June 30, 2024 of Union Electric Company (the “Registrant”) as filed by the Registrant with the Securities and Exchange Commission on the date hereof (the "Form 10-Q"), each undersigned officer of the Registrant does hereby certify, pursuant to 18 U.S.C. §1350, as adopted pursuant to §906 of the Sarbanes-Oxley Act of 2002, that:

(1)The Form 10-Q fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934 (15 U.S.C. 78m or 78o(d)); and

(2)The information contained in the Form 10-Q fairly presents, in all material respects, the financial condition and results of operations of the Registrant.

Date: August 5, 2024

 /s/ Mark C. Birk

Mark C. Birk
Chairman and President
(Principal Executive Officer)

 /s/ Michael L. Moehn

Michael L. Moehn
Senior Executive Vice President and Chief Financial Officer
(Principal Financial Officer)

EX-32.3

Exhibit 32.3

SECTION 1350 CERTIFICATION OF THE PRINCIPAL EXECUTIVE OFFICER

AND THE PRINCIPAL FINANCIAL OFFICER OF

AMEREN ILLINOIS COMPANY

(required by Section 906 of the Sarbanes-Oxley Act of 2002)

In connection with the report on Form 10-Q for the quarterly period ended June 30, 2024 of Ameren Illinois Company (the “Registrant”) as filed by the Registrant with the Securities and Exchange Commission on the date hereof (the "Form 10-Q"), each undersigned officer of the Registrant does hereby certify, pursuant to 18 U.S.C. §1350, as adopted pursuant to §906 of the Sarbanes-Oxley Act of 2002, that:

(1)The Form 10-Q fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934 (15 U.S.C. 78m or 78o(d)); and

(2)The information contained in the Form 10-Q fairly presents, in all material respects, the financial condition and results of operations of the Registrant.

Date: August 5, 2024

 /s/ Leonard P. Singh

Leonard P. Singh
Chairman and President
(Principal Executive Officer)

 /s/ Michael L. Moehn

Michael L. Moehn
Senior Executive Vice President and Chief Financial Officer
(Principal Financial Officer)

XML

Cover Page - shares	6 Months Ended
	Jun. 30, 2024	Jul. 31, 2024
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2024
Document Transition Report	false
Entity File Number	1-14756
Entity Registrant Name	Ameren Corporation
Entity Tax Identification Number	43-1723446
Entity Incorporation, State or Country Code	MO
Entity Address, Address Line One	1901 Chouteau Avenue
Entity Address, City or Town	St. Louis
Entity Address, State or Province	MO
Entity Address, Postal Zip Code	63103
City Area Code	(314)
Local Phone Number	621-3222
Title of 12(b) Security	Common Stock, $0.01 par value per share
Trading Symbol(s)	AEE
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Emerging growth company	false
Entity Shell Company	false
Shares outstanding		266,816,725
Entity Central Index Key	0001002910
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q2
Amendment Flag	false
Union Electric Company
Entity Information [Line Items]
Entity File Number	1-2967
Entity Registrant Name	Union Electric Company
Entity Tax Identification Number	43-0559760
Entity Incorporation, State or Country Code	MO
Entity Address, Address Line One	1901 Chouteau Avenue
Entity Address, City or Town	St. Louis
Entity Address, State or Province	MO
Entity Address, Postal Zip Code	63103
City Area Code	(314)
Local Phone Number	621-3222
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Emerging growth company	false
Entity Shell Company	false
Shares outstanding		102,123,834
Entity Central Index Key	0000100826
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q2
Amendment Flag	false
Ameren Illinois Company
Entity Information [Line Items]
Entity File Number	1-3672
Entity Registrant Name	Ameren Illinois Company
Entity Tax Identification Number	37-0211380
Entity Incorporation, State or Country Code	IL
Entity Address, Address Line One	10 Richard Mark Way
Entity Address, City or Town	Collinsville
Entity Address, State or Province	IL
Entity Address, Postal Zip Code	62234
City Area Code	(618)
Local Phone Number	343-8150
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Emerging growth company	false
Entity Shell Company	false
Shares outstanding		25,452,373
Entity Central Index Key	0000018654
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q2
Amendment Flag	false

XML

Consolidated Statement of Income (Loss) and Comprehensive Income - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Operating Revenues:
Total operating revenues	$ 1,693	$ 1,760	$ 3,509	$ 3,822
Operating Expenses:
Fuel and purchased power	327	480	655	1,088
Natural gas purchased for resale	33	42	184	250
Other operations and maintenance	465	450	935	898
Depreciation and amortization	376	335	737	655
Taxes other than income taxes	131	124	266	251
Total operating expenses	1,332	1,431	2,777	3,142
Operating Income	361	329	732	680
Other Income, Net	103	82	192	160
Interest Charges	165	134	319	261
Income Before Income Taxes	299	277	605	579
Income Taxes	39	38	83	75
Net Income	260	239	522	504
Less: Net Income Attributable to Noncontrolling Interests	2	2	3	3
Net Income Attributable to Ameren Common Shareholders	258	237	519	501
Pension and other postretirement benefit plan activity, net of income taxes (benefit)	(2)	(1)	(3)	(2)
Comprehensive Income	258	238	519	502
Less: Comprehensive Income Attributable to Noncontrolling Interests	2	2	3	3
Comprehensive Income Attributable to Ameren Common Shareholders	$ 256	$ 236	$ 516	$ 499
Earnings Per Share, Basic [Abstract]
Earnings per Common Share – Basic	$ 0.97	$ 0.90	$ 1.95	$ 1.91
Earnings Per Share, Diluted [Abstract]
Earnings per Common Share – Diluted	$ 0.97	$ 0.90	$ 1.95	$ 1.90
Weighted-average Common Shares Outstanding – Basic	266.7	262.6	266.5	262.4
Weighted-average Common Shares Outstanding – Diluted	266.8	263.2	266.8	263.2
Electric
Operating Revenues:
Total operating revenues	$ 1,521	$ 1,585	$ 2,885	$ 3,175
Natural gas
Operating Revenues:
Total operating revenues	172	175	624	647
Union Electric Company
Operating Revenues:
Total operating revenues	888	941	1,663	1,864
Operating Expenses:
Fuel and purchased power	189	289	355	610
Natural gas purchased for resale	9	9	37	56
Other operations and maintenance	247	237	501	476
Depreciation and amortization	208	186	403	362
Taxes other than income taxes	91	88	178	168
Total operating expenses	744	809	1,474	1,672
Operating Income	144	132	189	192
Other Income, Net	49	22	93	41
Interest Charges	63	52	125	103
Income Before Income Taxes	130	102	157	130
Income Taxes	1	(1)	2	(2)
Net Income	129	103	155	132
Preferred Stock Dividends	1	1	2	2
Net Income Attributable to Parent	128	102	153	130
Union Electric Company | Electric
Operating Revenues:
Total operating revenues	864	918	1,578	1,759
Union Electric Company | Natural gas
Operating Revenues:
Total operating revenues	24	23	85	105
Ameren Illinois Company
Operating Revenues:
Total operating revenues	766	779	1,766	1,880
Operating Expenses:
Purchased Power	141	192	305	479
Natural gas purchased for resale	24	33	147	194
Other operations and maintenance	224	201	434	403
Depreciation and amortization	154	138	307	271
Taxes other than income taxes	35	32	79	74
Total operating expenses	578	596	1,272	1,421
Operating Income	188	183	494	459
Other Income, Net	37	41	68	78
Interest Charges	60	50	115	97
Income Before Income Taxes	165	174	447	440
Income Taxes	40	44	107	112
Net Income	125	130	340	328
Preferred Stock Dividends	1	1	1	1
Net Income Attributable to Parent	124	129	339	327
Ameren Illinois Company | Electric
Operating Revenues:
Total operating revenues	618	627	1,227	1,337
Ameren Illinois Company | Natural gas
Operating Revenues:
Total operating revenues	$ 148	$ 152	$ 539	$ 543

XML

Consolidated Statement of Income (Loss) and Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Income Statement [Abstract]
Pension and other postretirement benefit plan activity, tax	$ (1)	$ 0	$ (1)	$ 0

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Consolidated Balance Sheet - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Current Assets:
Cash and cash equivalents	$ 19	$ 25
Accounts receivable - trade (less allowance for doubtful accounts)	514	494
Unbilled revenue	407	319
Miscellaneous accounts receivable	62	106
Inventories	740	733
Current regulatory assets	345	365
Other current assets	130	139
Total current assets	2,217	2,181
Property, Plant, and Equipment, Net	34,873	33,776
Investments and Other Assets:
Nuclear decommissioning trust fund	1,266	1,150
Goodwill	411	411
Regulatory assets	1,952	1,810
Pension and other postretirement benefits	566	581
Other assets	1,049	921
Total investments and other assets	5,244	4,873
TOTAL ASSETS	42,334	40,830
Current Liabilities:
Current maturities of long-term debt	799	849
Short-term debt	691	536
Accounts and wages payable	774	1,136
Interest accrued	177	147
Customer deposits	197	176
Other current liabilities	655	501
Total current liabilities	3,293	3,345
Long-term Debt, Net	16,280	15,121
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes and tax credits, net	4,325	4,176
Regulatory liabilities	5,531	5,512
Asset retirement obligations	791	772
Other deferred credits and liabilities	446	426
Total deferred credits and other liabilities	11,093	10,886
Commitments and Contingencies
Shareholders’ Equity:
Common Stock	3	3
Other paid-in capital, principally premium on common stock	7,246	7,216
Retained earnings	4,299	4,136
Accumulated other comprehensive loss	(9)	(6)
Total shareholders’ equity	11,539	11,349
Noncontrolling Interests	129	129
Total equity	11,668	11,478
TOTAL LIABILITIES AND EQUITY	42,334	40,830
Union Electric Company
Current Assets:
Cash and cash equivalents	0	0
Unbilled revenue	271	163
Miscellaneous accounts receivable	30	26
Inventories	520	508
Current regulatory assets	124	101
Other current assets	63	68
Total current assets	1,286	1,142
Property, Plant, and Equipment, Net	17,938	17,250
Investments and Other Assets:
Nuclear decommissioning trust fund	1,266	1,150
Regulatory assets	733	755
Pension and other postretirement benefits	138	157
Other assets	194	152
Total investments and other assets	2,331	2,214
TOTAL ASSETS	21,555	20,606
Current Liabilities:
Current maturities of long-term debt	0	350
Short-term debt	390	170
Borrowings from money pool	0	306
Interest accrued	82	69
Taxes accrued	132	28
Other current liabilities	234	153
Total current liabilities	1,262	1,747
Long-term Debt, Net	6,830	5,991
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes and tax credits, net	2,196	2,122
Regulatory liabilities	2,925	2,959
Asset retirement obligations	788	768
Other deferred credits and liabilities	88	56
Total deferred credits and other liabilities	5,997	5,905
Commitments and Contingencies
Shareholders’ Equity:
Common Stock	511	511
Other paid-in capital, principally premium on common stock	3,075	2,725
Preferred stock	80	80
Retained earnings	3,800	3,647
Total shareholders’ equity	7,466	6,963
TOTAL LIABILITIES AND EQUITY	21,555	20,606
Union Electric Company | Nonrelated Party
Current Assets:
Accounts receivable - trade (less allowance for doubtful accounts)	211	204
Current Liabilities:
Accounts and wages payable	366	618
Union Electric Company | Related Party
Current Assets:
Accounts receivable - trade (less allowance for doubtful accounts)	67	72
Current Liabilities:
Accounts and wages payable	58	53
Ameren Illinois Company
Current Assets:
Cash and cash equivalents	6	0
Advances to money pool	30	0
Unbilled revenue	136	156
Miscellaneous accounts receivable	5	44
Inventories	216	225
Current regulatory assets	215	252
Other current assets	55	62
Total current assets	961	1,047
Property, Plant, and Equipment, Net	15,009	14,632
Investments and Other Assets:
Goodwill	411	411
Regulatory assets	1,189	1,035
Pension and other postretirement benefits	412	394
Other assets	656	603
Total investments and other assets	2,668	2,443
TOTAL ASSETS	18,638	18,122
Current Liabilities:
Current maturities of long-term debt	300	0
Short-term debt	0	366
Borrowings from money pool	0	135
Customer deposits	161	141
Zero emission credit liabilities	64	35
Current regulatory liabilities	58	71
Other current liabilities	219	263
Total current liabilities	1,196	1,433
Long-term Debt, Net	5,551	5,232
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes and tax credits, net	1,967	1,906
Regulatory liabilities	2,466	2,418
Other deferred credits and liabilities	319	308
Total deferred credits and other liabilities	4,752	4,632
Commitments and Contingencies
Shareholders’ Equity:
Common Stock	0	0
Other paid-in capital, principally premium on common stock	3,020	3,020
Preferred stock	49	49
Retained earnings	4,070	3,756
Total shareholders’ equity	7,139	6,825
TOTAL LIABILITIES AND EQUITY	18,638	18,122
Ameren Illinois Company | Nonrelated Party
Current Assets:
Accounts receivable - trade (less allowance for doubtful accounts)	287	273
Current Liabilities:
Accounts and wages payable	297	370
Ameren Illinois Company | Related Party
Current Assets:
Accounts receivable - trade (less allowance for doubtful accounts)	11	35
Current Liabilities:
Accounts and wages payable	$ 97	$ 52

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Consolidated Balance Sheet (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Accounts Receivable, Allowance for Credit Loss, Current	$ 37	$ 30
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	400,000,000.0	400,000,000.0
Common Stock, Shares, Outstanding	266,800,000	266,300,000
Union Electric Company
Accounts Receivable, Allowance for Credit Loss, Current	$ 12	$ 12
Common stock, par value (in dollars per share)	$ 5	$ 5
Common stock, shares authorized (in shares)	150,000,000.0	150,000,000.0
Common Stock, Shares, Outstanding	102,100,000	102,100,000
Ameren Illinois Company
Accounts Receivable, Allowance for Credit Loss, Current	$ 25	$ 18
Common stock, no par value (in dollars per share)	$ 0	$ 0
Common stock, shares authorized (in shares)	45,000,000.0	45,000,000.0
Common Stock, Shares, Outstanding	25,500,000	25,500,000

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Consolidated Statement of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Cash Flows From Operating Activities:
Net income	$ 522	$ 504
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	760	703
Amortization of nuclear fuel	38	36
Amortization of debt issuance costs and premium/discounts	9	8
Deferred income taxes and investment tax credits, net	76	66
Allowance for equity funds used during construction	(25)	(23)
Stock-based compensation costs	14	14
Other	13	(19)
Changes in assets and liabilities:
Receivables	(85)	173
Inventories	(7)	(44)
Accounts and wages payable	(210)	(335)
Taxes accrued	121	93
Regulatory assets and liabilities	(105)	(81)
Assets, other	(53)	(38)
Liabilities, other	100	34
Pension and other postretirement benefits	(112)	(114)
Counterparty collateral, net	(7)	134
Net cash provided by operating activities	1,049	1,111
Cash Flows From Investing Activities:
Capital expenditures	(1,892)	(1,822)
Nuclear fuel expenditures	(37)	(50)
Purchases of securities – nuclear decommissioning trust fund	(323)	(81)
Sales and maturities of securities – nuclear decommissioning trust fund	309	65
Other	11	(1)
Net cash used in investing activities	(1,932)	(1,889)
Cash Flows From Financing Activities:
Dividends on common stock	(356)	(330)
Dividends paid to noncontrolling interest holders	(3)	(3)
Short-term debt, net	156	260
Maturities of long-term debt	(350)	(100)
Issuances of long-term debt	1,470	997
Issuances of common stock	21	16
Employee payroll taxes related to stock-based compensation	(8)	(20)
Debt issuance costs	(18)	(9)
Other	0	(3)
Net cash provided by financing activities	912	808
Net change in cash, cash equivalents, and restricted cash	29	30
Cash, cash equivalents, and restricted cash at beginning of year	272	216
Cash, cash equivalents, and restricted cash at end of period	301	246
Union Electric Company
Cash Flows From Operating Activities:
Net income	155	132
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	426	410
Amortization of nuclear fuel	38	36
Amortization of debt issuance costs and premium/discounts	3	3
Deferred income taxes and investment tax credits, net	38	10
Allowance for equity funds used during construction	(23)	(12)
Other	22	(20)
Changes in assets and liabilities:
Receivables	(121)	(9)
Inventories	(12)	(81)
Accounts and wages payable	(196)	(231)
Taxes accrued	118	103
Regulatory assets and liabilities	(31)	28
Assets, other	(30)	13
Liabilities, other	63	21
Pension and other postretirement benefits	(40)	(41)
Counterparty collateral, net	(3)	81
Net cash provided by operating activities	407	443
Cash Flows From Investing Activities:
Capital expenditures	(1,104)	(914)
Nuclear fuel expenditures	(37)	(50)
Purchases of securities – nuclear decommissioning trust fund	(323)	(81)
Sales and maturities of securities – nuclear decommissioning trust fund	309	65
Net cash used in investing activities	(1,155)	(980)
Cash Flows From Financing Activities:
Dividends on preferred stock	(2)	(2)
Short-term debt, net	220	44
Money pool borrowings, net	(306)	0
Maturities of long-term debt	(350)	0
Issuances of long-term debt	846	499
Capital contributions from parent	350	0
Debt issuance costs	(9)	(6)
Other	0	(3)
Net cash provided by financing activities	749	532
Net change in cash, cash equivalents, and restricted cash	1	(5)
Cash, cash equivalents, and restricted cash at beginning of year	10	13
Cash, cash equivalents, and restricted cash at end of period	11	8
Ameren Illinois Company
Cash Flows From Operating Activities:
Net income	340	328
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	307	271
Amortization of debt issuance costs and premium/discounts	2	2
Deferred income taxes and investment tax credits, net	37	70
Allowance for equity funds used during construction	(2)	(10)
Other	8	12
Changes in assets and liabilities:
Receivables	27	182
Inventories	9	37
Accounts and wages payable	7	(92)
Taxes accrued	55	(36)
Regulatory assets and liabilities	(70)	(105)
Assets, other	(23)	(42)
Liabilities, other	32	13
Pension and other postretirement benefits	(43)	(46)
Counterparty collateral, net	5	53
Net cash provided by operating activities	691	637
Cash Flows From Investing Activities:
Capital expenditures	(717)	(844)
Money pool advances, net	(30)	0
Other	5	(2)
Net cash used in investing activities	(742)	(846)
Cash Flows From Financing Activities:
Dividends on common stock	(25)	0
Dividends on preferred stock	(1)	(1)
Short-term debt, net	(366)	(147)
Money pool borrowings, net	(135)	0
Maturities of long-term debt	0	(100)
Issuances of long-term debt	624	498
Debt issuance costs	(7)	(3)
Net cash provided by financing activities	90	247
Net change in cash, cash equivalents, and restricted cash	39	38
Cash, cash equivalents, and restricted cash at beginning of year	234	191
Cash, cash equivalents, and restricted cash at end of period	$ 273	$ 229

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Consolidated Statement of Stockholders' Equity - USD ($) $ in Millions	Total	Common Stock	Other Paid-in Capital:	Retained Earnings:	Deferred Retirement Benefit Costs	Accumulated Other Comprehensive Loss:	Total Shareholders’ Equity	Noncontrolling Interests:	Union Electric Company	Union Electric Company Common Stock	Union Electric Company Other Paid-in Capital:	Union Electric Company Preferred Stock	Union Electric Company Retained Earnings:	Ameren Illinois Company	Ameren Illinois Company Common Stock	Ameren Illinois Company Other Paid-in Capital:	Ameren Illinois Company Preferred Stock	Ameren Illinois Company Retained Earnings:
Beginning of period at Dec. 31, 2022			$ 6,860	$ 3,646	$ (1)			$ 129			$ 2,725		$ 3,111					$ 3,190
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued under the DRPlus and 401(k) plan			23
Stock-based compensation activity			(3)
Net income	$ 504								$ 132				132	$ 328				328
Net income attributable to Ameren common shareholders	501			501
Dividends on common stock				(330)														0
Preferred stock dividends													(2)					(1)
Change in deferred retirement benefit costs	(2)				(2)
Net income attributable to noncontrolling interest holders	$ (3)							3
Dividends paid to noncontrolling interest holders								(3)
Common stock shares outstanding at beginning of period at Dec. 31, 2022	262,000,000.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued under the DRPlus and 401(k) plan	200,000
Shares issued for stock-based compensation	500,000
Common stock shares outstanding at end of period at Jun. 30, 2023	262,700,000
End of period at Jun. 30, 2023	$ 10,826	$ 3	6,880	3,817	(3)	$ (3)		129		$ 511	2,725	$ 80	3,241		$ 0	$ 2,929	$ 49	3,517
Shareholders' equity, end of year at Jun. 30, 2023							$ 10,697		6,557					6,495
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends per common share	$ 1.26
Beginning of period at Mar. 31, 2023			6,861	3,745	(2)			129			2,725		3,139					3,388
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued under the DRPlus and 401(k) plan			11
Stock-based compensation activity			8
Net income	$ 239								103				103	130				130
Net income attributable to Ameren common shareholders	237			237
Dividends on common stock				(165)														0
Preferred stock dividends													(1)					(1)
Change in deferred retirement benefit costs	(1)				(1)
Net income attributable to noncontrolling interest holders	$ (2)							2
Dividends paid to noncontrolling interest holders								(2)
Common stock shares outstanding at beginning of period at Mar. 31, 2023	262,600,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued under the DRPlus and 401(k) plan	100,000
Shares issued for stock-based compensation	0
Common stock shares outstanding at end of period at Jun. 30, 2023	262,700,000
End of period at Jun. 30, 2023	$ 10,826	3	6,880	3,817	(3)	(3)		129		511	2,725	80	3,241		0	2,929	49	3,517
Shareholders' equity, end of year at Jun. 30, 2023							10,697		$ 6,557					$ 6,495
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends per common share	$ 0.63
Beginning of period at Dec. 31, 2023	$ 11,478		7,216	4,136	(6)			129			2,725		3,647					3,756
Common stock shares outstanding at beginning of period at Dec. 31, 2023	266,300,000								102,100,000					25,500,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued for stock-based compensation	200,000
Common stock shares outstanding at end of period at Mar. 31, 2024	266,600,000
End of period at Mar. 31, 2024			7,228	4,219	(7)			129			2,725		3,672					3,971
Beginning of period at Dec. 31, 2023	$ 11,478		7,216	4,136	(6)			129			2,725		3,647					3,756
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued under the DRPlus and 401(k) plan			21
Stock-based compensation activity			9
Net income	522								$ 155				155	$ 340				340
Net income attributable to Ameren common shareholders	519			519
Dividends on common stock				(356)														(25)
Preferred stock dividends													(2)					(1)
Change in deferred retirement benefit costs	(3)				(3)
Net income attributable to noncontrolling interest holders	$ (3)							3
Dividends paid to noncontrolling interest holders								(3)
Common stock shares outstanding at beginning of period at Dec. 31, 2023	266,300,000								102,100,000					25,500,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued under the DRPlus and 401(k) plan	300,000
Shares issued for stock-based compensation	200,000
Common stock shares outstanding at end of period at Jun. 30, 2024	266,800,000								102,100,000					25,500,000
End of period at Jun. 30, 2024	$ 11,668	3	7,246	4,299	(9)	(9)		129		511	3,075	80	3,800		0	3,020	49	4,070
Shareholders' equity, end of year at Jun. 30, 2024	$ 11,539						11,539		$ 7,466					$ 7,139
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends per common share	$ 1.34
Beginning of period at Mar. 31, 2024			7,228	4,219	(7)			129			2,725		3,672					3,971
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued under the DRPlus and 401(k) plan			11
Stock-based compensation activity			7
Net income	$ 260								$ 129				129	$ 125				125
Net income attributable to Ameren common shareholders	258			258
Dividends on common stock				(178)														(25)
Preferred stock dividends													(1)					(1)
Change in deferred retirement benefit costs	(2)				(2)
Net income attributable to noncontrolling interest holders	$ (2)							2
Dividends paid to noncontrolling interest holders								(2)
Common stock shares outstanding at beginning of period at Mar. 31, 2024	266,600,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued under the DRPlus and 401(k) plan	200,000
Shares issued for stock-based compensation	0
Common stock shares outstanding at end of period at Jun. 30, 2024	266,800,000								102,100,000					25,500,000
End of period at Jun. 30, 2024	$ 11,668	$ 3	$ 7,246	$ 4,299	$ (9)	$ (9)		$ 129		$ 511	$ 3,075	$ 80	$ 3,800		$ 0	$ 3,020	$ 49	$ 4,070
Shareholders' equity, end of year at Jun. 30, 2024	$ 11,539						$ 11,539		$ 7,466					$ 7,139
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends per common share	$ 0.67

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Summary Of Significant Accounting Policies

6 Months Ended

Jun. 30, 2024

Accounting Policies [Abstract]

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

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 Illinois Company, doing business as Ameren Illinois, operates rate-regulated electric transmission, electric distribution, and natural gas distribution businesses in Illinois.

•ATXI operates a FERC rate-regulated electric transmission business in the MISO.

Ameren’s and Ameren Missouri’s financial statements are prepared on a consolidated basis and therefore include the accounts of their majority-owned subsidiaries. All intercompany transactions have been eliminated. Ameren Missouri’s subsidiaries were created for the ownership of renewable generation projects. Ameren Illinois has 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 statement 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 reporting periods. Actual results could differ from those estimates. The results of operations for an interim period may not give a true indication of results that may be expected for a full year. These financial statements should be read in conjunction with the financial statements and accompanying notes included in the Form 10-K.

Variable Interest Entities

As of June 30, 2024, and December 31, 2023, Ameren had unconsolidated variable interests in various equity method investments, primarily to advance clean and resilient energy technologies, totaling $75 million and $73 million, respectively, included in “Other assets” on Ameren’s consolidated balance sheet. Any earnings or losses related to these investments are included in “Other Income, Net” on Ameren’s consolidated statement of income and comprehensive income. Ameren is not the primary beneficiary of these investments because it does not have the power to direct matters that most significantly affect the activities of these variable interest entities. As of June 30, 2024, Ameren’s maximum exposure to loss related to these variable interests is limited to its investment of $75 million plus associated outstanding funding commitments of $12 million.

COLI

Ameren and Ameren Illinois have COLI, 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 June 30, 2024, the cash surrender value of COLI at Ameren and Ameren Illinois was $255 million (December 31, 2023 – $248 million) and $114 million (December 31, 2023 – $111 million), respectively, while total borrowings against the policies were $103 million (December 31, 2023 – $104 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. The net cash surrender value of Ameren’s COLI is affected by the investment performance of a separate account in which Ameren holds a beneficial interest.

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Rate And Regulatory Matters

6 Months Ended

Jun. 30, 2024

Public Utilities, General Disclosures [Abstract]

RATE AND REGULATORY MATTERS

RATE AND REGULATORY MATTERS

Below is a summary of updates to significant regulatory proceedings and related legal proceedings. See Note 2 – Rate and Regulatory Matters under Part II, Item 8, of the Form 10-K for additional information and a summary of our regulatory frameworks. We are unable to predict the ultimate outcome of these matters, the timing of final decisions of the various agencies and courts, or the impact on our results of operations, financial position, or liquidity.

Missouri

2024 Electric Service Regulatory Rate Review

In June 2024, Ameren Missouri filed a request with the MoPSC seeking approval to increase its annual revenues for electric service by $446 million. The electric rate increase request is based on a 10.25% return on common equity, a capital structure composed of 52% common equity, a rate base of $14 billion, and a test year ended March 31, 2024, with certain pro-forma adjustments expected through an anticipated true-up date of December 31, 2024. Ameren Missouri also requested the continued use of the FAC and trackers for pension and postretirement benefits, uncertain income tax positions, certain excess deferred income taxes, and the utilization of production and investment tax credits or proceeds from the sale of tax credits allowed under the IRA, which the MoPSC previously authorized in earlier electric rate orders. The electric rate increase request reflects the following:

•increased infrastructure investments made under Ameren Missouri’s Smart Energy Plan, including increased cost of capital and depreciation expense. Included in these investments are 500 megawatts of solar generation investment for the Boomtown, Cass County and Huck Finn solar projects along with investments in the Callaway nuclear energy center and other dispatchable generation to support a reliable, low-cost and cleaner mix of energy resources;

•decreased costs resulting from the planned retirement of the Rush Island Energy Center; and

•decreased costs related to the extension of the retirement date of the Sioux Energy Center from 2030 to 2032, consistent with Ameren Missouri’s integrated resource plan filed with the MoPSC in September 2023, to ensure reliability.

The MoPSC proceeding relating to the proposed electric service rate changes will take place over a period of up to 11 months, with a decision by the MoPSC expected by May 2025 and new rates effective by June 2025. Ameren Missouri cannot predict the level of any electric service rate change the MoPSC may approve, whether the requested regulatory recovery mechanisms will be continued, or whether any rate change that may eventually be approved will be sufficient for Ameren Missouri to recover its costs and earn a reasonable return on its investments when the rate change goes into effect.

Generation Facilities

During 2022 and 2023, Ameren Missouri, and certain subsidiaries of Ameren Missouri, entered into agreements to acquire and/or construct various generation facilities. The solar generation facilities are eligible for recovery under the PISA. The following table provides information with respect to each agreement:

	Agreement type	Facility size	Status of MoPSC CCN	Status of FERC approval of acquisition	Anticipated in-service date(a)
Huck Finn Solar Project(b)(c)	Build-transfer	200-MW	Approved February 2023	Received March 2023	Fourth quarter 2024
Boomtown Solar Project(c)(d)	Build-transfer	150-MW	Approved April 2023	Received October 2023	Fourth quarter 2024(e)
Cass County Solar Project(d)	Development-transfer(f)	150-MW	Approved June 2024	Not applicable	Fourth quarter 2024
Vandalia Solar Project(c)(g)	Self-build	50-MW	Approved March 2024	Not applicable	Fourth quarter 2025
Bowling Green Solar Project(c)(g)	Self-build	50-MW	Approved March 2024	Not applicable	First quarter 2026
Split Rail Solar Project(g)	Build-transfer	300-MW	Approved March 2024	Requested July 2024	Mid-2026
Castle Bluff Natural Gas Project	Self-build	800-MW	Filed June 2024	Not applicable	Fourth quarter 2027

(a)Anticipated in-service dates are dependent on the timing of regulatory approvals and construction completion, among other things.

(b)The Huck Finn Solar Project is expected to support Ameren Missouri’s compliance with the state of Missouri’s renewable energy standard. Investments in the project will be eligible for recovery under the RESRAM. Ameren Missouri expects to close on the acquisition of the Huck Finn Solar Project in the fourth quarter of 2024.

(c)These projects collectively represent approximately $0.85 billion of expected capital expenditures.

(d)The Boomtown and Cass County solar projects are expected to support Ameren Missouri’s transition to renewable energy generation and serve customers under the Renewable Solutions Program.

(e)Ameren Missouri expects to close on the acquisition of the Boomtown Solar Project in August 2024.

(f)In June 2024, Ameren Missouri acquired the Cass County Solar Project, which includes solar panels, project design, land rights, and engineering, procurement, and construction agreements, for approximately $250 million and took over construction management of the project.

(g)These solar projects are expected to support Ameren Missouri’s transition to renewable energy generation.

Securitization of Rush Island Energy Center Costs

In June 2024, the MoPSC issued a financing order authorizing the issuance of securitized utility tariff bonds by a wholly owned, special purpose subsidiary of Ameren Missouri to finance approximately $470 million of costs related to the planned accelerated retirement of the Rush Island Energy Center, which includes the expected remaining unrecovered net plant balance associated with the facility, among other costs. Ameren Missouri initially petitioned the MoPSC in November 2023 to finance $519 million of costs. The difference between the initial petition and final financing order will be considered for recovery in future rate proceedings involving the securitized utility tariff charge or base rates. Ameren Missouri will collect the amounts necessary to repay the bonds over approximately 15 years from the date of bond issuance. The financing order also includes a determination that the decision to retire the Rush Island Energy Center was reasonable and prudent. The MoPSC did not make a determination regarding the prudency of Ameren Missouri's prior actions that resulted in the adverse ruling in the NSR and Clean Air Act litigation discussed in Note 9 – Commitments and Contingencies. However, claims regarding such actions could be considered in future regulatory proceedings. If future regulatory proceedings result in revenue reductions based on Ameren Missouri’s prior actions that resulted in the adverse ruling in the NSR and Clean Air Act litigation, it could have a material adverse effect on the results of operations, financial position, and liquidity of Ameren and Ameren Missouri. In July 2024, the MoOPC filed a request for rehearing of the financing order. Ameren Missouri expects a decision on the rehearing request in August 2024. The decision on the rehearing request is subject to appeal. The timing of the issuance of securitized utility tariff bonds is dependent on the conclusion of any appeal process.

MEEIA

In January 2024, Ameren Missouri filed a proposed customer energy-efficiency plan with the MoPSC under the MEEIA. This filing proposed a three-year plan, which includes a portfolio of customer energy-efficiency programs, along with the continued use of the MEEIA rider, which allows Ameren Missouri to collect from customers its actual MEEIA program costs and related lost electric revenues. If the plan is approved, Ameren Missouri intends to invest $123 million annually in the proposed customer energy-efficiency programs from 2025 to 2027. In addition, Ameren Missouri requested performance incentives applicable to each plan year to earn revenues by achieving certain customer energy-efficiency savings and target spending goals. If 100% of the goals are achieved, Ameren Missouri would earn performance incentive revenues totaling $56 million over the three-year plan. Ameren Missouri also requested additional performance incentives applicable to each plan year totaling up to $14 million over the three-year plan, if Ameren Missouri exceeds 100% of the goals. In March 2024, the MoPSC staff and the MoOPC filed responses in opposition to the proposed customer energy-efficiency plan under the MEEIA. Ameren Missouri expects a decision by the MoPSC by October 2024, but cannot predict the ultimate outcome of this regulatory proceeding.

MISO Long-Range Transmission Projects CCN

In July 2022, the MISO approved the first tranche of projects related to a preliminary long-range transmission planning roadmap of projects through 2039. A portion of these projects were assigned or awarded via a competitive bid process to various utilities, including Ameren. In July 2024, ATXI filed a request for a CCN, among other things, with the MoPSC related to a portion of the MISO long-range transmission projects that it will construct within the MoPSC’s jurisdiction. A decision by the MoPSC is expected by mid-2025.

Illinois

MYRP

In December 2023, the ICC issued an order in Ameren Illinois' MYRP proceeding approving base rates for electric distribution services for 2024 through 2027 and rejecting Ameren Illinois' Grid Plan, which was addressed as part of the MYRP proceeding. Rate changes consistent with the December 2023 order became effective in January 2024 and remained effective through late June 2024, when new rates became effective pursuant to the June 2024 ICC rehearing order discussed below. The December 2023 order adopted an alternative methodology to establish a rate base and revenue requirements for the years 2024 through 2027 using Ameren Illinois’ previously approved 2022 year-end rate base. In January 2024, the ICC partially denied a rehearing requested by Ameren Illinois to revise the allowed ROE in the December 2023 order and granted Ameren Illinois’ rehearing request to reconsider the rate base for each year of the MYRP and to include a base level of investments to maintain grid reliability in each year of the MYRP. In June 2024, the ICC issued an order on Ameren Illinois’ rehearing request, which revised the rate bases for Ameren Illinois’ MYRP test years to include investments for 2023 through 2027, among other things. New rates became effective in late June 2024. For additional information on the ICC’s June 2024 rehearing order, see the table below. In July 2024, Ameren Illinois filed a request for rehearing of the ICC’s June 2024 rehearing order to include an asset associated with other postretirement benefits in the rate base. Subsequently, in August 2024, the ICC denied the rehearing request. The ICC rehearing denial

is subject to appeal. Also, in January 2024, Ameren Illinois filed an appeal of the December 2023 ICC order, including the 8.72% ROE, to the Illinois Appellate Court for the Fifth Judicial District. The court is under no deadline to address the appeal.

In July 2024, Ameren Illinois filed an update to its revised Grid Plan and revised MYRP to update the requested revenue requirements for 2024 through 2027. In July 2024, the ICC staff filed its recommendation regarding Ameren Illinois’ revised MYRP. An ICC decision on the revised Grid Plan and updated revenue requirements is expected by the end of 2024 with rates effective in January 2025.

The following table presents the approved revenue requirements and average annual rate base in the ICC’s June 2024 rehearing order, as well as the proposed revenue requirements and average annual rate base in Ameren Illinois’ July 2024 revised MYRP and the ICC staff’s July 2024 revised MYRP recommendation:

Year	Revenue Requirement (in millions)	Average Annual Rate Base (in billions)
ICC’s June 2024 Rehearing Order(a):
2024	$1,196	$4.0
2025	$1,282	$4.3
2026	$1,350	$4.5
2027	$1,397	$4.7
Ameren Illinois’ July 2024 Revised MYRP(a):
2024	$1,215	$4.3
2025	$1,300	$4.5
2026	$1,386	$4.8
2027	$1,446	$5.0
ICC Staff’s July 2024 Revised MYRP(a):
2024	$1,201	$4.2
2025	$1,281	$4.4
2026	$1,361	$4.6
2027	$1,414	$4.8

(a)Based on an allowed ROE of 8.72% and a capital structure composed of 50% common equity. The ROE is under appeal, as discussed above.

Using the 2023 revenue requirement as a starting point, the approved revenue requirements in the ICC’s June 2024 rehearing order represent a cumulative four-year increase of $285 million compared to a cumulative increase of $334 million in Ameren Illinois’ July 2024 revised MYRP and a cumulative increase of $302 million in the ICC staff’s July 2024 revised MYRP recommendation.

Ameren Illinois cannot predict the ultimate outcome of the appeal to the Illinois Appellate Court for the Fifth Judicial District, its revised Grid Plan filing, or its request to update the associated MYRP revenue requirements for 2024 through 2027.

2023 Electric Distribution Revenue Requirement Reconciliation Adjustment Request

In April 2024, Ameren Illinois filed for a reconciliation adjustment to its 2023 electric distribution service revenue requirement with the ICC. In July 2024, Ameren Illinois filed a revised reconciliation adjustment, requesting recovery of $158 million. The reconciliation adjustment reflects a capital structure composed of 50% common equity and Ameren Illinois’ actual 2023 recoverable costs and year-end rate base. In June 2024, the ICC staff submitted its calculation of the reconciliation adjustment, recommending recovery of $157 million. An ICC decision in this proceeding is required by December 2024, and any approved adjustment would be collected from customers in 2025. This is the final revenue requirement reconciliation under the IEIMA formula framework.

Electric Customer Energy-Efficiency Investments

In May 2024, Ameren Illinois filed its annual electric energy-efficiency formula rate update to increase its rates by $26 million with the ICC. An ICC decision in this proceeding is required by December 2024, with new rates effective January 2025.

2023 Natural Gas Delivery Service Rate Order

In November 2023, the ICC issued an order in Ameren Illinois’ January 2023 natural gas delivery service regulatory rate review, which resulted in an increase to its annual revenues for natural gas delivery service of $112 million based on a 9.44% allowed ROE, a capital structure composed of 50% common equity, and a rate base of approximately $2.85 billion. The order reflected a reduction of approximately $93 million of planned distribution and transmission capital investments included in Ameren Illinois’ requested revenue increase, which used a 2024 future test year. The new rates became effective on November 28, 2023.

In December 2023, Ameren Illinois filed a request for rehearing of the ICC’s November 2023 order. The filing requested the ICC revise the order to include an allowed ROE of at least 9.89%, a capital structure composed of 52% common equity, and the reversal of the approximately $93 million reduction of planned distribution and transmission capital investments included in the order, among other things. In January 2024, the ICC denied Ameren Illinois’ rehearing request. Subsequently, in January 2024, Ameren Illinois filed an appeal of the November 2023 ICC order to the Illinois Appellate Court for the Fifth Judicial District. The court is under no deadline to address the appeal. Ameren Illinois cannot predict the ultimate outcome of this appeal.

QIP Reconciliation Hearing

In March 2021, Ameren Illinois filed a request with the ICC to initiate a reconciliation proceeding to determine the accuracy and prudence of natural gas capital investments recovered under the QIP rider during 2020. In October 2023, the Illinois Attorney General’s office challenged the recovery of capital investments that were made during 2020, alleging that the ICC should disallow approximately $53 million in natural gas capital investments as improper and imprudent, providing a potential over-recovery of approximately $3 million in 2020. In October 2023, the ICC staff filed testimony that supports the prudence and reasonableness of the capital investments made during 2020. Ameren Illinois’ 2020 QIP rate recovery request under review by the ICC was within the rate increase limitations allowed by law. The ICC is under no deadline to issue an order in this proceeding. Ameren Illinois cannot predict the ultimate outcome of this regulatory proceeding.

MISO Long-Range Transmission Projects CCN

In July 2022, the MISO approved the first tranche of projects related to a preliminary long-range transmission planning roadmap of projects through 2039. A portion of these projects were assigned or awarded via a competitive bidding process to various utilities, including Ameren. In February 2024, Ameren Illinois and ATXI filed a request for a CCN, among other things, with the ICC related to the portion of the MISO long-range transmission projects they will construct within the ICC’s jurisdiction. A decision by the ICC is expected by mid-2025.

Federal

FERC Complaint Cases

Since November 2013, the allowed base ROE for FERC-regulated transmission rate base under the MISO tariff has been subject to customer complaint cases and has been changed by various FERC orders. In May 2020, the FERC issued an order, which set the allowed base ROE to 10.02% and required refunds, with interest, for the periods November 2013 to February 2015 and from late September 2016 forward. Ameren and Ameren Illinois paid these refunds, including interest, by March 31, 2022. In June and July 2020, Ameren Missouri, Ameren Illinois, and ATXI, as well as various customers, petitioned the United States Court of Appeals for the District of Columbia Circuit for review of the May 2020 order, challenging certain aspects of the new ROE methodology established. The petition filed by Ameren Missouri, Ameren Illinois, and ATXI challenged the refunds required for the period from September 2016 to May 2020. In August 2022, the court issued a ruling that granted the customers’ petition for review, vacated the FERC’s previous MISO ROE-determining orders, and remanded the proceedings to the FERC. The court elected not to rule on the issues raised by Ameren Missouri, Ameren Illinois, and ATXI. The currently allowed base ROE of 10.02% will remain effective for customer billings, but the transmission rates charged during previous periods and the currently effective rates may be subject to refund if the base ROE is changed by the FERC in a future order. The FERC is under no deadline to issue an order related to these proceedings. A 50-basis-point change in the FERC-allowed ROE would affect Ameren’s and Ameren Illinois’ annual revenue by an estimated $21 million and $15 million, respectively, based on each company’s 2024 projected rate base. Ameren and Ameren Illinois are unable to predict the ultimate resolution of this matter; however, such resolution could have a material effect on their results of operations, financial position, and liquidity.

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Short-Term Debt And Liquidity

6 Months Ended

Jun. 30, 2024

Debt Disclosure [Abstract]

SHORT-TERM DEBT AND LIQUIDITY

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, and, in the case of Ameren Missouri and Ameren Illinois, short-term affiliate borrowings. See Note 4 – Short-term Debt and Liquidity under Part II, Item 8, of the Form 10-K for a description of our indebtedness provisions and other covenants as well as a description of money pool agreements.

Short-term Borrowings

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, and the issuance of letters of credit. As of June 30, 2024, 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 $1.9 billion. The Ameren Companies were in compliance with the covenants in their Credit Agreements as of June 30, 2024. As of June 30, 2024, the ratios of consolidated indebtedness to consolidated total capitalization, calculated in accordance with the provisions of the Credit Agreements, were 61%, 49%, and 45% for Ameren, Ameren Missouri, and Ameren Illinois, respectively.

The following table presents commercial paper outstanding, net of issuance discounts, as of June 30, 2024, and December 31, 2023. There were no borrowings outstanding under the Credit Agreements as of June 30, 2024, or December 31, 2023.

	June 30, 2024		December 31, 2023
Ameren (parent)	$	301	$	—
Ameren Missouri	390		170
Ameren Illinois	—		366
Ameren consolidated	$	691	$	536

The following table summarizes the activity and relevant interest rates for Ameren (parent)’s, Ameren Missouri’s, and Ameren Illinois’ commercial paper issuances and borrowings under the Credit Agreements in the aggregate for the six months ended June 30, 2024 and 2023:

	Ameren (parent)			Ameren Missouri			Ameren Illinois			Ameren Consolidated
2024
Average daily amount outstanding	$	84		$	109		$	385		$	578
Weighted-average interest rate	5.55		%	5.53		%	5.57		%	5.56		%
Peak amount outstanding during period(a)	$	301		$	509		$	694		$	1,084
Peak interest rate	5.60		%	5.68		%	5.68		%	5.68		%
2023
Average daily amount outstanding	$	595		$	343		$	230		$	1,168
Weighted-average interest rate	5.14		%	5.04		%	5.10		%	5.10		%
Peak amount outstanding during period(a)	$	841		$	592		$	450		$	1,381
Peak interest rate	5.55		%	5.55		%	5.60		%	5.60		%

(a)The timing of peak outstanding commercial paper issuances and borrowings under the Credit Agreements varies by company. Therefore, the sum of individual company peak amounts may not equal the Ameren consolidated peak amount for the period.

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. The average interest rate for borrowings under the utility money pool for the three and six months ended June 30, 2024, was 5.51% and 5.41%, respectively (2023 – 5.28% and 5.04%, respectively). See Note 8 – Related-party Transactions for the amount of interest income and expense from the utility money pool agreements recorded by Ameren Missouri and Ameren Illinois for the three and six months ended June 30, 2024 and 2023.

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Long-Term Debt And Equity Financings

6 Months Ended

Jun. 30, 2024

Long-Term Debt And Equity Financings [Abstract]

LONG-TERM DEBT AND EQUITY FINANCINGS

LONG-TERM DEBT AND EQUITY FINANCINGS

Ameren

For the three and six months ended June 30, 2024, Ameren issued a total of 0.2 million and 0.3 million shares of common stock, under its DRPlus and 401(k) plan, and received proceeds of $4 million and $14 million, respectively. As of June 30, 2024, Ameren had a receivable of $7 million related to issuances of common stock under its DRPlus. In addition, in the first quarter of 2024, Ameren issued 0.2 million shares of common stock valued at $16 million upon the settlement of stock-based compensation awards.

There were no shares issued under the ATM program for the three and six months ended June 30, 2024. As of June 30, 2024, Ameren had approximately $770 million of common stock available for sale under the ATM program, which takes into account the forward sale agreements in effect as of June 30, 2024, discussed below.

The forward sale agreements outstanding as of June 30, 2024, can be settled at Ameren’s discretion on or prior to dates ranging from October 3, 2024 to February 28, 2025. On a settlement date or dates, if Ameren elects to physically settle a forward sale agreement, Ameren will issue shares of common stock to the counterparties at the then-applicable forward sale price. The initial forward sale price for the agreements ranged from $76.69 to $89.31, with an average initial forward sale price of $80.45. Each initial forward sale price is subject to adjustment based on a floating interest rate factor equal to the overnight bank funding rate less a spread of 75 basis points, and will be subject to decrease on certain dates specified in the forward sale agreements by specified amounts related to expected dividends on shares of the common stock during the term of the forward sale agreements. If the overnight bank funding rate is less than the spread on any day, the interest rate factor will result in a reduction of the forward sale price. The forward sale agreements will be physically settled unless Ameren elects to settle in cash or to net share settle. At June 30, 2024, Ameren could have settled the forward sale agreements with physical delivery of 2.9 million shares of common stock to the respective counterparties in exchange for cash of $232 million. Alternatively, the forward sale agreements could have also been settled at June 30, 2024, with the counterparties delivering approximately $29 million of cash or approximately 0.4 million shares of common stock to Ameren. In connection with the forward sale agreements outstanding at June 30, 2024, the various counterparties, or their affiliates, borrowed from third parties and sold 2.9 million shares of common stock. The gross sales price of these shares totaled $232 million. Ameren has not received any proceeds from such sales of borrowed shares. The forward sale agreements have been classified as equity transactions.

Ameren Missouri

In January 2024, Ameren Missouri issued $350 million of 5.25% first mortgage bonds due January 2054, with interest payable semiannually on January 15 and July 15 of each year, beginning July 15, 2024. Net proceeds from this issuance were used for capital expenditures and to repay short-term debt.

In April 2024, Ameren Missouri issued $500 million of 5.20% first mortgage bonds due April 2034, with interest payable semiannually on April 1 and October 1 of each year, beginning October 1, 2024. Net proceeds from this issuance were used for capital expenditures and to repay short-term debt.

In April 2024, $350 million principal amount of Ameren Missouri’s 3.50% senior secured notes matured and were repaid with cash on hand.

Ameren Missouri received capital contributions totaling $350 million from Ameren (parent) during the three and six months ended June 30, 2024.

Ameren Illinois

In June 2024, Ameren Illinois issued $625 million of 5.55% first mortgage bonds due July 2054, with interest payable semiannually on January 1 and July 1 of each year, beginning January 1, 2025. Net proceeds from this issuance were used to repay short-term debt.

Indenture Provisions and Other Covenants

See Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of the Form 10-K for a description of our indenture provisions and other covenants, as well as restrictions on the payment of dividends. At June 30, 2024, 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 agreements.

Off-balance-sheet Arrangements

At June 30, 2024, none of the Ameren Companies had any material off-balance-sheet financing arrangements, other than their investment in variable interest entities and the multiple forward sale agreements under the ATM program relating to common stock. See Note 1 – Summary of Significant Accounting Policies for further detail concerning variable interest entities.

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Other Income, Net

6 Months Ended

Jun. 30, 2024

Other Nonoperating Income (Expense) [Abstract]

OTHER INCOME, NET

OTHER INCOME, NET

The following table presents the components of “Other Income, Net” in the Ameren Companies’ statements of income for the three and six months ended June 30, 2024 and 2023:

	Three Months				Six Months
	2024		2023		2024		2023
Ameren:
Allowance for equity funds used during construction	$	16	$	14	$	25	$	23
Other interest income	13		9		21		17
Non-service cost components of net periodic benefit income(a)	76		63		152		127
Miscellaneous income	4		2		6		4
Earnings related to equity method investments	1		—		1		2
Donations	(2)		(2)		(4)		(4)
Miscellaneous expense	(5)		(4)		(9)		(9)
Total Other Income, Net	$	103	$	82	$	192	$	160
Ameren Missouri:
Allowance for equity funds used during construction	$	14	$	8	$	23	$	12
Other interest income	3		2		5		6
Non-service cost components of net periodic benefit income(a)	35		14		69		28
Miscellaneous income	—		1		2		2
Donations	(1)		(1)		(2)		(2)
Miscellaneous expense	(2)		(2)		(4)		(5)
Total Other Income, Net	$	49	$	22	$	93	$	41
Ameren Illinois:
Allowance for equity funds used during construction	$	2	$	6	$	2	$	10
Other interest income	9		6		15		10
Non-service cost components of net periodic benefit income	26		31		53		62
Miscellaneous income	2		1		3		2
Donations	(1)		(1)		(2)		(2)
Miscellaneous expense	(1)		(2)		(3)		(4)
Total Other Income, Net	$	37	$	41	$	68	$	78

(a)For the three and six months ended June 30, 2024, the non-service cost components of net periodic benefit income were adjusted by amounts deferred of $(11) million and $(20) million, respectively, 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. The deferral was $17 million and $34 million, respectively, for the three and six months ended June 30, 2023. See Note 11 – Retirement Benefits for additional information.

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Derivative Financial Instruments

6 Months Ended

Jun. 30, 2024

Derivative Instruments and Hedging Activities Disclosure [Abstract]

DERIVATIVE FINANCIAL INSTRUMENTS

DERIVATIVE FINANCIAL INSTRUMENTS

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

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

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

•actual cash outlays for the purchase of these commodities that differ from anticipated cash outlays; and

•actual off-system sales revenues that differ from anticipated revenues.

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.

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. 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. The following disclosures exclude NPNS contracts and other non-derivative commodity contracts that are accounted for under the accrual method of accounting.

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 June 30, 2024, and December 31, 2023, all contracts that met the definition of a derivative and were not eligible for the NPNS exception received regulatory deferral. The cash flows from our derivative financial instruments follow the cash flow classification of the hedged item.

The following table presents open gross commodity contract volumes by commodity type for derivative assets and liabilities as of June 30, 2024, and December 31, 2023. As of June 30, 2024, these contracts extended through October 2027, October 2029 and May 2032 for fuel oils, natural gas and power, respectively.

	Quantity (in millions)
	June 30, 2024			December 31, 2023
Commodity	Ameren Missouri	Ameren Illinois	Ameren	Ameren Missouri	Ameren Illinois	Ameren
Fuel oils (in gallons)	20	—	20	17	—	17
Natural gas (in mmbtu)	52	221	273	53	218	271
Power (in MWhs)	—	5	5	—	5	5
Uranium (pounds in thousands)	—	—	—	186	—	186

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 June 30, 2024, and December 31, 2023:

		June 30, 2024						December 31, 2023
	Balance Sheet Location	Ameren Missouri		Ameren Illinois		Ameren			Ameren Missouri		Ameren Illinois		Ameren
Fuel oils	Other current assets	$	2	$	—	$	2		$	2	$	—	$	2
Natural gas	Other current assets	1		3		4			—		—		—
	Other assets	2		1		3			3		3		6
Power	Other current assets	15		—		15			5		—		5
Uranium	Other current assets	—		—		—			9		—		9
	Total assets	$	20	$	4	$	24		$	19	$	3	$	22
Fuel oils	Other current liabilities	$	1	$	—	$	1		$	1	$	—	$	1
	Other deferred credits and liabilities	—		—		—			1		—		1
Natural gas	Other current liabilities	9		33		42			12		45		57
	Other deferred credits and liabilities	8		28		36			10		30		40
Power	Other current liabilities	1		11		12			1		12		13
	Other deferred credits and liabilities	—		50		50			—		56		56
	Total liabilities	$	19	$	122	$	141		$	25	$	143	$	168

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 following table provides the recognized gross derivative balances and the net amounts of those derivatives subject to an enforceable master netting arrangement or similar agreement as of June 30, 2024, and December 31, 2023:

			Gross Amounts Not Offset in the Balance Sheet
Commodity Contracts Eligible to be Offset	Gross Amounts Recognized in the Balance Sheet		Derivative Instruments		Cash Collateral Received/Posted(a)		Net Amount
June 30, 2024
Assets:
Ameren Missouri	$	20	$	5	$	—	$	15
Ameren Illinois	4		2		—		2
Ameren	$	24	$	7	$	—	$	17
Liabilities:
Ameren Missouri	$	19	$	5	$	—	$	14
Ameren Illinois	122		2		—		120
Ameren	$	141	$	7	$	—	$	134
December 31, 2023
Assets:
Ameren Missouri	$	19	$	6	$	—	$	13
Ameren Illinois	3		1		—		2
Ameren	$	22	$	7	$	—	$	15
Liabilities:
Ameren Missouri	$	25	$	6	$	—	$	19
Ameren Illinois	143		1		6		136
Ameren	$	168	$	7	$	6	$	155

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

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. As of June 30, 2024, if counterparty groups were to fail completely to perform on contracts, the Ameren Companies’ maximum exposure related to derivative assets, predominantly from financial institutions, would have been immaterial with or without consideration of the application of master netting arrangements or similar agreements and collateral held.

Certain of our derivative instruments 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 additional collateral required is the net liability position allowed under master netting arrangements or similar agreements, assuming (1) the credit risk-related contingent features underlying these arrangements were triggered and (2) those counterparties with rights to do so requested collateral. The following table presents, as of June 30, 2024, 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:

	Aggregate Fair Value of Derivative Liabilities(a)		Cash Collateral Posted		Potential Aggregate Amount of Additional Collateral Required(b)
Ameren Missouri	$	19	$	—	$	13
Ameren Illinois	61		—		59
Ameren	$	80	$	—	$	72

(a)Before consideration of master netting arrangements or similar agreements.

(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

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Fair Value Measurements

6 Months Ended

Jun. 30, 2024

Fair Value Disclosures [Abstract]

Fair Value Disclosures

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. Fair value measurements are classified in three levels based on the fair value hierarchy as defined by GAAP. See Note 8 – Fair Value Measurements under Part II, Item 8, of the Form 10-K for information related to hierarchy levels and valuation techniques.

We consider nonperformance risk in our valuation of derivative instruments by analyzing our own credit standing and the credit standing of our counterparties, and by considering any credit enhancements (e.g., collateral). 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 the three and six months ended June 30, 2024 or 2023. At June 30, 2024, and December 31, 2023, 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 June 30, 2024, and December 31, 2023:

		June 30, 2024									December 31, 2023
		Level 1		Level 2		Level 3		Total			Level 1		Level 2		Level 3		Total
Assets:
Ameren Missouri
	Derivative assets – commodity contracts:
	Fuel oils	$	1	$	—	$	1	$	2		$	2	$	—	$	—	$	2
	Natural gas	—		3		—		3			—		3		—		3
	Power	—		—		15		15			—		—		5		5
	Uranium	—		—		—		—			—		—		9		9
	Total derivative assets – commodity contracts	$	1	$	3	$	16	$	20		$	2	$	3	$	14	$	19
	Nuclear decommissioning trust fund:
	Equity securities:
	U.S. large capitalization	$	842	$	—	$	—	$	842		$	787	$	—	$	—	$	787
	Debt securities:
	U.S. Treasury and agency securities	—		178		—		178			—		150		—		150
	Corporate bonds	—		154		—		154			—		136		—		136
	Other	—		82		—		82			—		68		—		68
	Total nuclear decommissioning trust fund	$	842	$	414	$	—	$	1,256	(a)	$	787	$	354	$	—	$	1,141	(a)
	Total Ameren Missouri	$	843	$	417	$	16	$	1,276		$	789	$	357	$	14	$	1,160
Ameren Illinois
	Derivative assets – commodity contracts:
	Natural gas	—		1		3		4			—		1		2		3
	Total Ameren Illinois	$	—	$	1	$	3	$	4		$	—	$	1	$	2	$	3
Ameren
	Derivative assets – commodity contracts(b)	$	1	$	4	$	19	$	24		$	2	$	4	$	16	$	22
	Nuclear decommissioning trust fund(c)	842		414		—		1,256		(a)	787		354		—		1,141		(a)
	Total Ameren	$	843	$	418	$	19	$	1,280		$	789	$	358	$	16	$	1,163
Liabilities:
Ameren Missouri
	Derivative liabilities – commodity contracts:
	Fuel oils	$	1	$	—	$	—	$	1		$	2	$	—	$	—	$	2
	Natural gas	—		16		1		17			—		19		3		22
	Power	—		—		1		1			—		—		1		1
	Total Ameren Missouri	$	1	$	16	$	2	$	19		$	2	$	19	$	4	$	25
Ameren Illinois
	Derivative liabilities – commodity contracts:
	Natural gas	$	2	$	52	$	7	$	61		$	4	$	60	$	11	$	75
	Power	—		—		61		61			—		—		68		68
	Total Ameren Illinois	$	2	$	52	$	68	$	122		$	4	$	60	$	79	$	143
Ameren
	Derivative liabilities – commodity contracts(b)	$	3	$	68	$	70	$	141		$	6	$	79	$	83	$	168

(a)Balance excludes $10 million and $9 million of cash and cash equivalents, receivables, payables, and accrued income, net, for June 30, 2024, and December 31, 2023, respectively.

(b)See the Ameren Missouri and Ameren Illinois sections of the table for a breakout of the fair value of Ameren’s derivative assets and liabilities by type of commodity.

(c)See the Ameren Missouri section of the table for a breakout of the fair value of Ameren’s nuclear decommissioning trust fund by investment type.

Level 3 fuel oils, natural gas, and uranium 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 three and six months ended June 30, 2024 and 2023:

	2024						2023
	Ameren Missouri		Ameren Illinois		Ameren		Ameren Missouri		Ameren Illinois		Ameren
For the three months ended June 30:
Beginning balance at April 1	$	2	$	(54)	$	(52)	$	5	$	(52)	$	(47)
Realized and unrealized gains/(losses) included in regulatory assets/liabilities	15		(12)		3		14		(20)		(6)
Settlements	(3)		5		2		(5)		4		(1)
Ending balance at June 30	$	14	$	(61)	$	(47)	$	14	$	(68)	$	(54)
Change in unrealized gains/(losses) related to assets/liabilities held at June 30	$	14	$	(12)	$	2	$	14	$	(20)	$	(6)
For the six months ended June 30:
Beginning balance at January 1	$	4	$	(68)	$	(64)	$	12	$	(33)	$	(21)
Realized and unrealized gains/(losses) included in regulatory assets/liabilities	14		(2)		12		8		(41)		(33)
Settlements	(4)		9		5		(6)		6		—
Ending balance at June 30	$	14	$	(61)	$	(47)	$	14	$	(68)	$	(54)
Change in unrealized gains/(losses) related to assets/liabilities held at June 30	$	14	$	—	$	14	$	14	$	(35)	$	(21)

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 either net income or other comprehensive 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 June 30, 2024, and December 31, 2023:

			Fair Value						Weighted Average(b)
	Commodity		Assets		Liabilities	Valuation Technique(s)	Unobservable Input(a)	Range
2024	Power(c)	$	15	$	(62)	Discounted cash flow	Average forward peak and off-peak pricing – forwards/swaps ($/MWh)	33 – 70	43
							Nodal basis ($/MWh)	(10) – (1)	(5)
2023	Power(c)	$	5	$	(69)	Discounted cash flow	Average forward peak and off-peak pricing – forwards/swaps ($/MWh)	31 – 65	43
							Nodal basis ($/MWh)	(8) – (1)	(5)

(a)Generally, significant increases (decreases) in these inputs in isolation would result in a significantly higher (lower) fair value measurement.

(b)Unobservable inputs were weighted by relative fair value.

(c)Valuations use visible forward prices adjusted for nodal-to-hub basis differentials.

The following table sets forth the carrying amount and, by level within the fair value hierarchy, the fair value of long-term debt (including current portion) disclosed, but not recorded, at fair value as of June 30, 2024, and December 31, 2023:

Long-Term Debt (Including Current Portion):	Carrying Amount(a)		Fair Value
			Level 2		Level 3			Total
	June 30, 2024
Ameren	$	17,079	$	14,990	$	460	(b)	$	15,450
Ameren Missouri	6,830		6,069		—			6,069
Ameren Illinois	5,851		5,251		—			5,251
	December 31, 2023
Ameren	$	15,970	$	14,366	$	467	(b)	$	14,833
Ameren Missouri	6,341		5,800		—			5,800
Ameren Illinois	5,232		4,867		—			4,867

(a)Included unamortized debt issuance costs, which were excluded from the fair value measurement, of $124 million, $53 million, and $52 million for Ameren, Ameren Missouri, and Ameren Illinois, respectively, as of June 30, 2024. Included unamortized debt issuance costs, which were excluded from the fair value measurement, of $111 million, $45 million, and $47 million for Ameren, Ameren Missouri, and Ameren Illinois, respectively, as of December 31, 2023.

(b)The Level 3 fair value amount consists of ATXI’s senior unsecured notes.

The Ameren Companies’ carrying amounts of cash, cash equivalents, and restricted cash approximate fair value and are considered Level 1 in the fair value hierarchy. The Ameren Companies’ short-term borrowings approximate fair value because of the short-term nature of these instruments and are considered Level 2 in the fair value hierarchy.

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Related Party Transactions

6 Months Ended

Jun. 30, 2024

Related Party Transactions [Abstract]

RELATED PARTY TRANSACTIONS

RELATED-PARTY TRANSACTIONS

In the ordinary 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. For a discussion of material related-party agreements and money pool agreements, see Note 13 – Related-party Transactions and Note 4 – Short-term Debt and Liquidity under Part II, Item 8, of the Form 10-K.

Support Services Agreements

Ameren Missouri and Ameren Illinois had long-term receivables included in “Other assets” from Ameren Services of $22 million and $24 million, respectively, as of June 30, 2024, and $31 million and $34 million, respectively, as of December 31, 2023, related to Ameren Services’ allocated portion of Ameren’s pension and postretirement benefit plans.

In December 2023, ATXI placed in service a transmission operations control center. Rental revenues received by ATXI from Ameren Services associated with this facility are affiliate transactions and are eliminated in consolidation for Ameren’s consolidated financial statements. Ameren Services’ rental expenses incurred are subsequently allocated to Ameren Missouri and Ameren Illinois as part of the Ameren Services support agreement.

Tax Allocation Agreement

See Note 1 – Summary of Significant Accounting Policies under Part II, Item 8, of the Form 10-K 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 June 30, 2024, and December 31, 2023:

	June 30, 2024				December 31, 2023
	Ameren Missouri		Ameren Illinois		Ameren Missouri		Ameren Illinois
Income taxes payable to parent(a)	$	—	$	44	$	—	$	2
Income taxes receivable from parent(b)	54		—		56		22

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

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

Effects of Related-party Transactions on the Statement of Income

The following table presents the impact on Ameren Missouri and Ameren Illinois of related-party transactions for the three and six months ended June 30, 2024 and 2023:

				Three Months				Six Months
Agreement	Income Statement Line Item			Ameren Missouri		Ameren Illinois		Ameren Missouri		Ameren Illinois
Ameren Missouri power supply	Operating Revenues	2024	$	(b)	$	(a)	$	(b)	$	(a)
agreements with Ameren Illinois		2023		(b)		(a)		(b)		(a)
Ameren Missouri and Ameren Illinois	Operating Revenues	2024	$	8	$	(b)	$	15	$	(b)
rent and facility services		2023		8		(b)		18		(b)
Ameren Missouri and Ameren Illinois miscellaneous	Operating Revenues	2024	$	1	$	(b)	$	1	$	1
support services		2023		(b)		(b)		(b)		(b)
Total Operating Revenues		2024	$	9	$	(b)	$	16	$	1
		2023		8		(b)		18		(b)
Ameren Illinois power supply	Purchased Power	2024	$	(a)	$	(b)	$	(a)	$	(b)
agreements with Ameren Missouri		2023		(a)		(b)		(a)		(b)
Ameren Missouri and Ameren Illinois	Purchased Power	2024	$	2	$	1	$	4	$	1
transmission services from ATXI		2023		1		(b)		1		(b)
Total Purchased Power		2024	$	2	$	1	$	4	$	1
		2023		1		(b)		1		(b)
Ameren Missouri and Ameren Illinois	Other Operations and Maintenance	2024	$	(b)	$	(b)	$	(b)	$	(b)
rent and facility services		2023		(b)		(b)		(b)		2
Ameren Services support services	Other Operations and Maintenance	2024	$	43	$	40	$	81	$	77
agreement		2023		35		33		70		68
Total Other Operations and		2024	$	43	$	40	$	81	$	77
Maintenance		2023		35		33		70		70
Money pool interest	(Interest Charges)/Other Income, Net	2024	$	(b)	$	(b)	$	(3)	$	(2)
		2023		(b)		(b)		(b)		(b)

(a)Not applicable.

(b)Amount less than $1 million.

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Commitments And Contingencies

6 Months Ended

Jun. 30, 2024

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

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 the notes to our financial statements in this report and in the Form 10-K, will not have a material adverse effect on our results of operations, financial position, or liquidity.

Reference is made to Note 1 – Summary of Significant Accounting Policies, Note 2 – Rate and Regulatory Matters, Note 9 – Callaway Energy Center, Note 13 – Related-party Transactions, and Note 14 – Commitments and Contingencies under Part II, Item 8, of the Form 10-K. See also Note 1 – Summary of Significant Accounting Policies, Note 2 – Rate and Regulatory Matters, Note 8 – Related-party Transactions, and Note 10 – Callaway Energy Center of this report.

Environmental Matters

Our electric generation, transmission, and distribution and natural gas distribution and storage operations must comply with a variety of statutes and regulations relating to the protection of the environment and human health and safety, including permitting programs implemented by federal, state, and local authorities. Such environmental laws address air emissions; discharges to water bodies; the storage, handling and disposal of hazardous substances and waste materials; siting and land use requirements; and potential ecological impacts. Complex and lengthy processes are required to obtain and renew approvals, permits, and licenses for new, existing, or modified energy-related facilities. Additionally, the use and handling of various chemicals or hazardous materials require release prevention plans and emergency response procedures. We employ dedicated personnel knowledgeable in environmental matters to oversee our business activities’ compliance with requirements of environmental laws.

Environmental regulations have a significant impact on the electric utility industry and compliance with these regulations could be costly for Ameren Missouri, which operates coal-fired power plants. Regulations under the Clean Air Act that apply to 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. Regulations implementing the Clean Water Act govern both intake and discharges of water, as well as evaluation of the ecological and biological impact of those operations, and could require modifications to water intake structures or more stringent limitations on wastewater discharges. Depending upon the scope of modifications ultimately required by state regulators, capital expenditures associated with these modifications could be significant. The management and disposal of coal ash is regulated under the Resource Conservation and Recovery Act and the CCR Rule, which require the closure of surface impoundments at Ameren Missouri’s coal-fired energy centers. The individual or combined effects of compliance with existing and new 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.

Additionally, Ameren Missouri’s wind generation facilities may be subject to operating restrictions to limit the impact on protected species. Since 2021, Ameren Missouri’s High Prairie Renewable Energy Center curtailed nighttime operations from April through October to limit impacts on protected species during the critical biological season. Seasonal nighttime curtailment began again in April 2024, but the extent and duration of the curtailment is currently unknown as assessment of mitigation technologies is ongoing. Ameren Missouri does not anticipate these operating curtailments will have a material impact on its results of operations, financial position, or liquidity.

Ameren and Ameren Missouri estimate that they will need to make capital expenditures of $90 million to $120 million from 2024 through 2028 to comply with environmental regulations. These estimates exclude capital expenditures that may be necessary to comply with regulations issued by the EPA in 2024 relating to CO2 emissions, MATS, effluent limitations guidelines, and CCR management, which Ameren and Ameren Missouri are assessing and are discussed below. Additional capital expenditures for environmental controls beyond 2028 could be required. This estimate of capital expenditures includes surface impoundment closure and corrective action measures required by the 2015 CCR Rule and modifications to cooling water intake structures at existing power plants under Clean Water Act rules in place prior to 2024, all of which are discussed below. In addition to planned retirements of coal-fired energy centers identified in the 2023 IRP filed with the MoPSC in September 2023 and as noted below with respect to the NSR and Clean Air Act litigation and Illinois emissions standards discussed in Note 14 – Commitments and Contingencies under Part II, Item 8, of the Form 10-K, Ameren Missouri’s current plan for compliance with existing air emission regulations includes burning low-sulfur coal and installing new or optimizing existing air pollution control equipment. The actual amount of capital expenditures required to comply with existing environmental regulations may vary substantially from the above estimates because of uncertainty as to future permitting requirements by state regulators and the EPA, revisions to regulatory obligations, and varying cost of potential compliance strategies, among other things.

The following sections describe the more significant environmental statutes and regulations and environmental enforcement and remediation matters that affect or could affect our operations. The EPA periodically amends and revises its regulations and proposes amendments to regulations and guidelines, which could ultimately result in the revision of all or part of such regulations.

Clean Air Act

Federal and state laws, including the CSAPR, regulate emissions of SO2 and NOx through the reduction of emissions at their source and the use and retirement of emission allowances. In April 2022, the EPA proposed the Good Neighbor Rule of the Clean Air Act, which includes additional NOx emission reductions from power plants in Missouri, Illinois, and other states through revisions to the CSAPR. In January 2023, the EPA issued its final disapproval of Missouri’s proposed state implementation plan for addressing the transport of ozone under the Good Neighbor Rule of the Clean Air Act. The disapproval of the state plan allows the EPA to implement revisions to the CSAPR through a federal implementation plan. In March 2023, the EPA announced federal implementation plan requirements, which were subsequently published to the Federal Register in June 2023, reducing the amount of NOx allowances available for state budgets and imposing NOx emission limits on electric generating units for Missouri, Illinois, and other states under the Good Neighbor Rule of the Clean Air Act. In April 2023, the Missouri Attorney General and Ameren Missouri separately filed lawsuits in the United States Court of Appeals for the Eighth Circuit challenging the EPA’s disapproval of the Missouri state plan and sought a stay of the EPA’s disapproval of the Missouri state plan. The United States Court of Appeals for the Eighth Circuit in May 2023 granted those stay motions thereby preventing the EPA from imposing the federal implementation plan until the court of appeals issues a ruling. In June 2024, the United States Supreme Court granted applications to stay the EPA’s imposition of the federal implementation plan until resolution of appellate court challenges. Ameren Missouri complies with the current CSAPR requirements by minimizing emissions through the use of low-sulfur coal, operation of two scrubbers at its Sioux Energy Center, and optimization of existing NOx air pollution control equipment. Reducing the amount of state budget NOx allowances for compliance with NOx emission limits could result in additional controls being required on Ameren Missouri’s generating units and/or the reduction of operations. Any additional costs for compliance are expected to be recovered from customers, subject to MoPSC prudence review, through the FAC or higher base rates.

CO2 Emissions Standards

In June 2022, the United States Supreme Court issued its decision in West Virginia v. EPA, clarifying that there are limits on how the EPA may regulate greenhouse gases absent further direction from the United States Congress. The court concluded that the EPA’s proposed rules were designed to shift generation from fossil-fuel-fired power plants to renewable energy facilities, which was improper absent specific congressional authorization. In response to that ruling, in April 2024, the EPA issued a final rule that sets CO2 emission standards for existing coal-fired and new natural gas-fired power plants that relies on the adoption of carbon capture technology and/or natural gas co-firing for coal-fired power plants and carbon capture technology for new natural gas-fired power plants. Affected power plants are required to comply with the rule through a phased-in approach or retire. In July 2024, the United States Court of Appeals for the District of Columbia Circuit denied a request for stay by various stakeholders including state attorney generals and industry groups but indicated it would establish an expedited schedule regarding the legal merits of the final rule. Subsequently in July 2024, motions for stay of the final rule were filed with the United States Supreme Court. Ameren and Ameren Missouri are monitoring the legal challenges and assessing the impacts of the final rule and, at this time, cannot predict the impacts on their results of operations, financial position, and liquidity.

MATS

In April 2024, the EPA revised the MATS by establishing a more stringent standard for emissions of particulate matter, requiring the use of continuous emissions monitoring systems. Ameren and Ameren Missouri are assessing the impacts of the revised rule and, at this time, cannot predict the impacts on their results of operations, financial position, and liquidity.

NSR and Clean Air Act Litigation

In January 2011, the United States 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 alleging that projects performed in 2007 and 2010 at the coal-fired Rush Island Energy Center violated provisions of the Clean Air Act and Missouri law. In January 2017, the district court issued a liability ruling against Ameren Missouri and, in September 2019, entered a remedy order that required Ameren Missouri to install a flue gas desulfurization system at the Rush Island Energy Center and a dry sorbent injection system at the Labadie Energy Center. Following an appeal from Ameren Missouri, in August 2021, the United States Court of Appeals for the Eighth Circuit affirmed the liability ruling and the district court’s remedy order as it related to the installation of a flue gas desulfurization system at the Rush Island Energy Center, but reversed the order as it related to the installation of a dry sorbent injection system at the Labadie Energy Center. In September 2023, the district court granted Ameren Missouri’s request to modify the remedy order to allow the retirement of the Rush Island Energy Center in advance of its previously expected retirement date of 2039 in lieu of installing a flue gas desulfurization system. In its amended remedy order, the district court established an October 15, 2024 retirement date to allow for the completion of various transmission reliability projects and, in the interim, authorized Ameren Missouri to operate the energy center only as needed and as directed by the MISO. The United States Department of Justice is seeking an order from the district court providing for additional mitigation relief related to prior emissions. Ameren Missouri contends that the retirement of the Rush Island Energy Center, which eliminates all future emissions from the energy center, mitigates claims relating to prior emissions. In March 2024, the district court ordered Ameren Missouri and the United States Department of Justice to file proposed draft orders outlining additional mitigation relief. In May 2024, Ameren Missouri filed a proposed draft order that includes retiring the Rush Island Energy Center, a program to provide electric buses and charging stations to schools in the metro St. Louis area, a program to provide air filters to eligible Ameren Missouri electric residential customers, and the retirement of SO2 allowances. Excluding the accelerated retirement of the Rush Island Energy Center, these programs are estimated to cost approximately $20 million. Also in May 2024, the United States Department of Justice filed a proposed draft order that includes a program to provide electric buses and charging stations to schools in the metro St. Louis area and a program to provide air filters to eligible Ameren Missouri electric residential customers. These programs include a significantly greater number of buses, charging stations, and air filters than Ameren Missouri’s proposal and the United States Department of Justice estimates these programs would cost approximately $120 million. A mediation proceeding related to the potential additional mitigation relief is scheduled for September 2024. As of June 30, 2024, Ameren and Ameren Missouri recorded a $20 million liability in “Other current liabilities” on their consolidated balance sheets related to the cost of potential additional mitigation, which represents the estimated minimum liability, as no other amount within the range was a better estimate. Ameren Missouri could be required to implement some or all of the additional mitigation relief programs included in the United States Department of Justice’s proposed draft order, the costs of which could be material and could adversely impact Ameren and Ameren Missouri’s results of operations and financial position. Depending on the scope and basis of any final order issued by the district court, which is expected by the end of 2024, Ameren Missouri or the United States Department of Justice could appeal any additional mitigation relief ordered.

The MISO designated the Rush Island Energy Center as a system support resource in 2022 and concluded that certain reliability mitigation measures, including transmission upgrades, should occur before the energy center is retired. The Rush Island Energy Center began operating as a system support resource on September 1, 2022. In 2024, the MISO extended the system support resource designation through Rush Island Energy Center’s retirement date of October 15, 2024. In July 2024, an agreement between Ameren Missouri and the MISO was filed with the FERC for approval regarding the continued operation of the energy center during peak demand times and emergencies. Construction activities are ongoing for the transmission upgrades approved by the MISO, with the majority of the upgrades

expected to be completed in the fall of 2024. Ameren Missouri expects to complete the last of the necessary upgrades by mid-2025. Related to this matter, in February 2022, the MoPSC issued an order directing the MoPSC staff to review the planned accelerated retirement of the Rush Island Energy Center. See Note 2 – Rate and Regulatory Matters Part II, Item 8, of the Form 10-K for additional information.

In connection with the accelerated retirement of the Rush Island Energy Center, the MoPSC issued an order in June 2024 authorizing Ameren Missouri to finance the costs associated with the retirement, including the remaining unrecovered net plant balance associated with the facility, through the issuance of securitized utility tariff bonds pursuant to Missouri’s securitization statute. Costs associated with the retirement would exclude any additional mitigation relief ordered in the NSR and Clean Air Act litigation discussed above. See Note 2 – Rate and Regulatory Matters for additional information. As of June 30, 2024, the Rush Island Energy Center had a net plant balance of $508 million included in plant to be abandoned, net, within “Property, Plant, and Equipment, Net”. See Note 1 – Summary of Significant Accounting Policies under Part II, Item 8, of the Form 10-K for additional information regarding plant to be abandoned, net.

Clean Water Act

Among other items, the Clean Water Act requires power plant operators to evaluate cooling water intake structures and identify measures for reducing the number of 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 this cooling water intake structures rule. Requirements of the rule are implemented by state regulators through the permit renewal process of each power plant’s water discharge permit. Permits for Ameren Missouri’s coal-fired and nuclear energy centers have been issued or are in the process of renewal.

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, prohibit effluent discharges of certain waste streams, and impose more stringent limitations on certain water discharges from power plants by 2025. To comply with these guidelines, Ameren Missouri installed dry ash handling systems and wastewater treatment facilities at its coal-fired energy centers. In April 2024, the EPA issued new effluent limitation guidelines that established a zero discharge limit for flue gas desulfurization wastewater, bottom ash transport water, and combustion residual leachate. Ameren and Ameren Missouri expect the impacts of the new guidelines on their results of operations, financial position, and liquidity to be immaterial.

CCR Management

The EPA’s 2015 CCR Rule establishes requirements for the management and disposal of CCR from coal-fired power plants and has resulted in the closure of surface impoundments at Ameren Missouri’s energy centers, with closures of surface impoundments in process at its Sioux Energy Center and retired Meramec Energy Center. Ameren Missouri plans to substantially complete the closures of remaining surface impoundments by the end of 2026. Ameren Missouri’s CCR management compliance plan includes installation of groundwater monitoring equipment and groundwater treatment facilities. In April 2024, the EPA revised the CCR Rule to impose groundwater monitoring, and corrective action, closure, and post-closure requirements on certain active and inactive CCR surface impoundments and management disposal units. Ameren and Ameren Missouri have AROs of $42 million associated with CCR storage facilities recorded on their respective balance sheets as of June 30, 2024. This amount includes an immaterial incremental ARO related to the 2024 CCR Rule, which will be revised as additional site studies are performed. Ameren and Ameren Missouri are assessing the impacts of this rule revision and, at this time, cannot predict the final impacts on their results of operations, financial position, and liquidity.

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.

As of June 30, 2024, Ameren Illinois has remediated the majority of the 44 former MGP sites in Illinois with an estimated remaining obligation primarily related to three of these former MGP sites at $45 million to $95 million. Ameren and Ameren Illinois recorded a liability of $45 million to represent the estimated minimum obligation for these sites, as no other amount within the range was a better estimate. Ameren cannot estimate the completion date of the estimated remaining obligation due to site accessibility, among other things.

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 actual costs, including unanticipated underground structures, the degree to which groundwater is impacted, regulatory changes, local ordinances, and site accessibility. The actual costs and timing of completion may vary substantially from these estimates.

The ICC allows Ameren Illinois to recover MGP remediation and related litigation costs from its electric and natural gas utility customers through environmental cost riders that are subject to annual prudence reviews by the ICC.

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 historical practices will result in future environmental commitments, including additional or more stringent cleanup standards, or will affect our results of operations, financial position, or liquidity.

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Callaway Energy Center

6 Months Ended

Jun. 30, 2024

Nuclear Waste Matters [Abstract]

CALLAWAY ENERGY CENTER

CALLAWAY ENERGY CENTER

See Note 9 – Callaway Energy Center under Part II, Item 8, of the Form 10-K for information regarding spent nuclear fuel recovery, recovery of decommissioning costs, and the nuclear decommissioning trust fund. 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. 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 December 2023 and is reflected within the ARO. Ameren Missouri’s filing supported no change in electric service rates for decommissioning costs. There is no deadline by which the MoPSC must issue an order regarding the filing. See Note 13 – Supplemental Information for more information on Ameren Missouri’s AROs.

Insurance

The following table presents insurance coverage at Ameren Missouri’s Callaway Energy Center at April 1, 2024:

Type and Source of Coverage	Most Recent Renewal Date	Maximum Coverages			Maximum Assessments for Single Incidents
Public liability and nuclear worker liability:
American Nuclear Insurers	January 1, 2024	$	500		$	—
Pool participation	(a)	15,763		(a)	166		(b)
		$	16,263	(c)	$	166
Property damage:
NEIL and EMANI	April 1, 2024	$	3,200	(d)	$	28	(e)
Accidental outage:
NEIL	April 1, 2024	$	490	(f)	$	11	(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 $500 million in the event of an incident at any licensed United States commercial reactor, payable at $24.7 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 power reactors.

(d)NEIL provides $2.7 billion in property damage, stabilization, decontamination, and premature decommissioning insurance for radiation events and $0.7 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)Accidental outage insurance provides for lost sales 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 $291 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 October 2023. 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, resulting from terrorist attacks. 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 insurance limits, 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.

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Retirement Benefits

6 Months Ended

Jun. 30, 2024

Retirement Benefits [Abstract]

RETIREMENT BENEFITS

RETIREMENT BENEFITS

The following table presents the components of the net periodic benefit cost (income) incurred for Ameren’s pension and postretirement benefit plans for the three and six months ended June 30, 2024 and 2023:

	Pension Benefits								Postretirement Benefits
	Three Months				Six Months				Three Months				Six Months
	2024		2023		2024		2023		2024		2023		2024		2023
Service cost(a)	$	23	$	23	$	44	$	46	$	3	$	3	$	6	$	6
Non-service cost components:
Interest cost	56		56		111		111		11		12		22		23
Expected return on plan assets(b)	(82)		(84)		(164)		(167)		(23)		(23)		(46)		(46)
Amortization of(b):
Prior service benefit	—		—		—		—		(1)		(1)		(2)		(2)
Actuarial (gain)	(16)		(28)		(33)		(57)		(10)		(12)		(20)		(23)
Total non-service cost components(c)	$	(42)	$	(56)	$	(86)	$	(113)	$	(23)	$	(24)	$	(46)	$	(48)
Net periodic benefit income(d)	$	(19)	$	(33)	$	(42)	$	(67)	$	(20)	$	(21)	$	(40)	$	(42)

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

(b)Prior service benefit is amortized on a straight-line basis over the average future service of active participants benefiting under a plan amendment. Net actuarial gains or losses related to the net benefit obligation subject to amortization are amortized on a straight-line basis over 10 years. The difference between the actual and expected return on plan assets is amortized over 4 years.

(c)Non-service cost components are reflected in “Other Income, Net” on Ameren’s consolidated statement of income. See Note 5 – Other Income, Net for additional information.

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

Ameren Missouri and Ameren Illinois are responsible for their respective share of Ameren’s pension and other postretirement costs. The following table presents the respective share of net periodic pension and other postretirement benefit costs (income) incurred for the three and six months ended June 30, 2024 and 2023:

	Pension Benefits								Postretirement Benefits
	Three Months				Six Months				Three Months				Six Months
	2024		2023		2024		2023		2024		2023		2024		2023
Ameren Missouri(a)	$	(10)	$	(17)	$	(22)	$	(35)	$	(7)	$	(7)	$	(14)	$	(15)
Ameren Illinois	(8)		(13)		(17)		(27)		(13)		(14)		(26)		(27)
Other	(1)		(3)		(3)		(5)		—		—		—		—
Ameren(a)	$	(19)	$	(33)	$	(42)	$	(67)	$	(20)	$	(21)	$	(40)	$	(42)

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

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Income Taxes

6 Months Ended

Jun. 30, 2024

Income Tax Disclosure [Abstract]

Income Taxes

INCOME TAXES

The following table presents a reconciliation of the federal statutory corporate income tax rate to the effective income tax rate for the three and six months ended June 30, 2024 and 2023:

	Ameren				Ameren Missouri				Ameren Illinois
	2024		2023		2024		2023		2024		2023
Three Months
Federal statutory corporate income tax rate	21	%	21	%	21	%	21	%	21	%	21	%
Increases (decreases) from:
Amortization of excess deferred taxes(a)	(8)		(7)		(14)		(15)		(4)		(2)
Renewable and other tax credits(b)	(4)		(5)		(8)		(10)		—		—
State tax	5		5		3		3		7		7
Depreciation differences	(1)		—		(1)		—		—		(1)
Effective income tax rate	13	%	14	%	1	%	(1)	%	24	%	25	%
Six Months
Federal statutory corporate income tax rate	21	%	21	%	21	%	21	%	21	%	21	%
Increases (decreases) from:
Amortization of excess deferred taxes(a)	(8)		(8)		(14)		(15)		(4)		(2)
Renewable and other tax credits(b)	(4)		(4)		(8)		(10)		—		—
State tax	5		5		3		3		7		7
Depreciation differences	—		—		—		—		—		(1)
Other permanent items	—		(1)		—		—		—		—
Effective income tax rate	14	%	13	%	2	%	(1)	%	24	%	25	%

(a)Reflects the amortization of amounts resulting from the revaluation of deferred income taxes subject to regulatory ratemaking, which are being refunded to customers. Deferred income taxes are revalued when federal or state income tax rates change, and the offset to the revaluation of deferred income taxes subject to regulatory ratemaking is recorded to a regulatory asset or liability.

(b)The benefit of the credits associated with Missouri renewable energy standard compliance is refunded to customers through the RESRAM.

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Supplemental Information

6 Months Ended

Jun. 30, 2024

Supplemental Information [Abstract]

Supplemental Information

SUPPLEMENTAL INFORMATION

Cash, Cash Equivalents, and Restricted Cash

The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the balance sheets and the statements of cash flows at June 30, 2024, and December 31, 2023:

	June 30, 2024						December 31, 2023
	Ameren		Ameren Missouri		Ameren Illinois		Ameren		Ameren Missouri		Ameren Illinois
“Cash and cash equivalents”	$	19	$	—	$	6	$	25	$	—	$	—
Restricted cash included in “Other current assets”	18		7		7		13		5		5
Restricted cash included in “Other assets”	260		—		260		229		—		229
Restricted cash included in “Nuclear decommissioning trust fund”	4		4		—		5		5		—
Total cash, cash equivalents, and restricted cash	$	301	$	11	$	273	$	272	$	10	$	234

Restricted cash included in “Other current assets” primarily represents funds held by an irrevocable Voluntary Employee Beneficiary Association (VEBA) trust, which provides health care benefits for active employees. Restricted cash included in “Other assets” on Ameren’s and Ameren Illinois’ balance sheets primarily represents amounts collected under a cost recovery rider restricted for use in the procurement of renewable energy credits and amounts in a trust fund restricted for the use of funding certain asbestos-related claims.

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 June 30, 2024, and December 31, 2023, “Other current liabilities” on Ameren’s and Ameren Illinois’ balance sheets included payables for purchased receivables of $49 million and $42 million, respectively.

The following table provides a reconciliation of the beginning and ending amount of the allowance for doubtful accounts for the three and six months ended June 30, 2024 and 2023:

	Three Months				Six Months
	2024		2023		2024		2023
Ameren:
Beginning of period	$	37	$	34	$	30	$	31
Bad debt expense	6		13		16		23
Charged to other accounts(a)	1		1		4		1
Net write-offs	(7)		(9)		(13)		(16)
End of period	$	37	$	39	$	37	$	39
Ameren Missouri:
Beginning of period	$	11	$	12	$	12	$	13
Bad debt expense	4		2		5		4
Net write-offs	(3)		(2)		(5)		(5)
End of period	$	12	$	12	$	12	$	12
Ameren Illinois:(b)
Beginning of period	$	26	$	22	$	18	$	18
Bad debt expense	2		11		11		19
Charged to other accounts(a)	1		1		4		1
Net write-offs	(4)		(7)		(8)		(11)
End of period	$	25	$	27	$	25	$	27

(a)Amounts associated with the allowance for doubtful accounts related to receivables purchased by Ameren Illinois from alternative retail electric suppliers, as required by the Illinois Public Utilities Act.

(b)Ameren Illinois has rate-adjustment mechanisms that allow it to recover the difference between its actual net bad debt write-offs under GAAP, including those associated with receivables purchased from alternative retail electric suppliers, and the amount of net bad debt write-offs included in its base rates. The table above does not include the impact related to the riders.

Supplemental Cash Flow Information

The following table provides noncash financing and investing activity excluded from the statements of cash flows for the six months ended June 30, 2024 and 2023:

	June 30, 2024						June 30, 2023
	Ameren		Ameren Missouri		Ameren Illinois		Ameren		Ameren Missouri		Ameren Illinois
Investing:
Accrued capital expenditures, including nuclear fuel expenditures	$	380	$	232	$	134	$	325	$	132	$	173
Net realized and unrealized gain – nuclear decommissioning trust fund	103		103		—		105		105		—
Return of investment in industrial development revenue bonds(a)	—		—		—		240		240		—
Financing:
Issuance of common stock for stock-based compensation	$	16	$	—	$	—	$	37	$	—	$	—
Issuance of common stock under the DRPlus	7		—		—		7		—		—
Termination of a financing obligation(a)	—		—		—		240		240		—

(a)In January 2023, Ameren Missouri and Audrain County mutually agreed to terminate a financing obligation agreement related to the CT energy center in Audrain County, which was scheduled to expire in December 2023. No cash was exchanged in connection with the termination of the agreement as the $240 million principal amount of the financing obligation due from Ameren Missouri was equal to the amount of bond service payments due to Ameren Missouri.

Asset Retirement Obligations

The following table provides a reconciliation of the beginning and ending carrying amount of AROs for the six months ended June 30, 2024:

	Ameren Missouri			Ameren Illinois			Ameren
Balance at December 31, 2023	$	787	(a)	$	4	(b)	$	791	(a)
Liabilities incurred	7		(c)	—			7		(c)
Liabilities settled	(4)			(1)			(5)
Accretion	17		(d)	—			17		(d)
Balance at June 30, 2024	$	807	(a)	$	3	(b)	$	810	(a)

(a)Balance included $19 million in “Other current liabilities” on the balance sheet as of both June 30, 2024, and December 31, 2023.

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

(c)In June 2024, Ameren and Ameren Missouri recorded an ARO related to the decommissioning for the Cass County Solar Project. In addition, as a result of the 2024 CCR Rule, Ameren and Ameren Missouri recorded an immaterial increase to their AROs associated with CCR storage facilities. See Note 9 – Commitments and Contingencies for additional information.

(d)Accretion expense attributable to Ameren Missouri was recorded as a decrease to regulatory liabilities.

Stock-based Compensation

In the first quarter of 2024, Ameren granted 359,133 performance share units with a grant date fair value of $21 million and 153,887 restricted share units with a grant date fair value of $11 million. Awards vest approximately 3 years after the grant date based on continued employment or on a pro-rata basis upon death or eligible retirement. The performance share units vest based on the achievement of certain specified market performance measures (307,816 performance share units) or clean energy transition targets (51,317 performance share units). The exact number of shares issued pursuant to a performance share unit varies from 0% to 200% of the target award, depending on actual company performance relative to the performance goals.

For the six months ended June 30, 2024 and 2023, excess tax benefits (deficiencies) associated with the settlement of stock-based compensation awards increased income tax expense by $1 million and reduced income tax expense by $6 million, respectively.

Deferred Compensation

At June 30, 2024, and December 31, 2023, the present value of benefits to be paid for deferred compensation obligations was $80 million and $85 million, respectively, which was primarily reflected in “Other deferred credits and liabilities” on Ameren’s consolidated balance sheet.

Operating Revenues

As of June 30, 2024 and 2023, our remaining performance obligations for contracts with a term greater than one year were immaterial. 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.

See Note 14 – Segment Information for disaggregated revenue information.

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 three and six months ended June 30, 2024 and 2023:

	Three Months				Six Months
	2024		2023		2024		2023
Ameren Missouri	$	41	$	39	$	76	$	73
Ameren Illinois	28		26		65		63
Ameren	$	69	$	65	$	141	$	136

Earnings per Share

The following table reconciles the basic weighted-average number of common shares outstanding to the diluted weighted-average number of common shares outstanding for the three and six months ended June 30, 2024 and 2023:

	Three Months		Six Months
	2024	2023	2024	2023
Weighted-average Common Shares Outstanding – Basic	266.7	262.6	266.5	262.4
Assumed settlement of performance share units and restricted stock units	0.1	0.6	0.3	0.8
Weighted-average Common Shares Outstanding – Diluted(a)	266.8	263.2	266.8	263.2

(a)There was an immaterial number of anti-dilutive performance share units excluded from the earnings per diluted share calculations for the three and six months ended June 30, 2024 and 2023. The outstanding forward sale agreements as of June 30, 2024 and 2023, were anti-dilutive for the three and six months ended June 30, 2024 and 2023, and were excluded from the earnings per diluted share calculation as calculated using the treasury stock method. For additional information about the outstanding forward sale agreements, see Note 4 – Long-term Debt and Equity Financings.

XML

Segment Information

6 Months Ended

Jun. 30, 2024

Segment Reporting [Abstract]

SEGMENT INFORMATION

SEGMENT INFORMATION

The following tables present revenues, net income attributable to common shareholders, and capital expenditures by segment at Ameren and Ameren Illinois for the three and six months ended June 30, 2024 and 2023. Ameren, Ameren Missouri, and Ameren Illinois management review segment capital expenditure information rather than any individual or total asset amount. For additional information about our segments, see Note 16 – Segment Information under Part II, Item 8, of the Form 10-K.

Ameren

	Ameren Missouri		Ameren Illinois Electric Distribution		Ameren Illinois Natural Gas		Ameren Transmission			Other		Intersegment Eliminations		Ameren
Three Months 2024:
External revenues	$	879	$	509	$	148	$	157		$	—	$	—	$	1,693
Intersegment revenues	9		—		—		34			—		(43)		—
Net income (loss) attributable to Ameren common shareholders	128		61		6		79		(a)	(16)		—		258
Capital expenditures	638		132		59		175			2		(4)		1,002
Three Months 2023:
External revenues	$	933	$	540	$	152	$	135		$	—	$	—	$	1,760
Intersegment revenues	8		—		—		26			—		(34)		—
Net income (loss) attributable to Ameren common shareholders	102		66		11		72		(a)	(14)		—		237
Capital expenditures	433		180		90		197			2		(11)		891
Six Months 2024:
External revenues	$	1,647	$	1,015	$	539	$	308		$	—	$	—	$	3,509
Intersegment revenues	16		—		—		68			—		(84)		—
Net income (loss) attributable to Ameren common shareholders	153		117		112		151		(a)	(14)		—		519
Capital expenditures	1,104		316		119		341			4		8		1,892
Six Months 2023:
External revenues	$	1,846	$	1,164	$	543	$	269		$	—	$	—	$	3,822
Intersegment revenues	18		—		—		55			—		(73)		—
Net income attributable to Ameren common shareholders	130		127		98		143		(a)	3		—		501
Capital expenditures	914		350		141		410			5		2		1,822

(a)Ameren Transmission earnings reflect 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
Three Months 2024:
External revenues	$	509	$	148	$	109	$	—	$	766
Intersegment revenues	—		—		27		(27)		—
Net income available to common shareholder	61		6		57		—		124
Capital expenditures	132		59		153		—		344
Three Months 2023:
External revenues	$	540	$	152	$	87	$	—	$	779
Intersegment revenues	—		—		26		(26)		—
Net income available to common shareholder	66		11		52		—		129
Capital expenditures	180		90		167		—		437
Six Months 2024:
External revenues	$	1,015	$	539	$	212	$	—	$	1,766
Intersegment revenues	—		—		55		(55)		—
Net income available to common shareholder	117		112		110		—		339
Capital expenditures	316		119		282		—		717
Six Months 2023:
External revenues	$	1,164	$	543	$	173	$	—	$	1,880
Intersegment revenues	—		—		54		(54)		—
Net income available to common shareholder	127		98		102		—		327
Capital expenditures	350		141		353		—		844

The following tables present disaggregated revenues by segment at Ameren and Ameren Illinois for the three and six months ended June 30, 2024 and 2023. 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, off-system sales, and capacity revenues.

Ameren

	Ameren Missouri		Ameren Illinois Electric Distribution			Ameren Illinois Natural Gas		Ameren Transmission		Intersegment Eliminations		Ameren
Three Months 2024:
Residential	$	395	$	311		$	—	$	—	$	—	$	706
Commercial	324		163			—		—		—		487
Industrial	77		47			—		—		—		124
Other	68		(12)		(a)	—		191		(43)		204
Total electric revenues	$	864	$	509		$	—	$	191	$	(43)	$	1,521
Residential	$	13	$	—		$	102	$	—	$	—	$	115
Commercial	5		—			24		—		—		29
Industrial	1		—			1		—		—		2
Other	5		—			21		—		—		26
Total natural gas revenues	$	24	$	—		$	148	$	—	$	—	$	172
Total revenues(b)	$	888	$	509		$	148	$	191	$	(43)	$	1,693

	Ameren Missouri		Ameren Illinois Electric Distribution			Ameren Illinois Natural Gas		Ameren Transmission		Intersegment Eliminations		Ameren
Three Months 2023:
Residential	$	360	$	337		$	—	$	—	$	—	$	697
Commercial	311		193			—		—		—		504
Industrial	75		48			—		—		—		123
Other	172		(38)		(a)	—		161		(34)		261
Total electric revenues	$	918	$	540		$	—	$	161	$	(34)	$	1,585
Residential	$	13	$	—		$	98	$	—	$	—	$	111
Commercial	6		—			25		—		—		31
Industrial	1		—			2		—		—		3
Other	3		—			27		—		—		30
Total natural gas revenues	$	23	$	—		$	152	$	—	$	—	$	175
Total revenues(b)	$	941	$	540		$	152	$	161	$	(34)	$	1,760
Six Months 2024:
Residential	$	736	$	608		$	—	$	—	$	—	$	1,344
Commercial	583		328			—		—		—		911
Industrial	138		92			—		—		—		230
Other	121		(13)		(a)	—		376		(84)		400
Total electric revenues	$	1,578	$	1,015		$	—	$	376	$	(84)	$	2,885
Residential	$	53	$	—		$	389	$	—	$	—	$	442
Commercial	21		—			92		—		—		113
Industrial	3		—			5		—		—		8
Other	8		—			53		—		—		61
Total natural gas revenues	$	85	$	—		$	539	$	—	$	—	$	624
Total revenues(b)	$	1,663	$	1,015		$	539	$	376	$	(84)	$	3,509
Six Months 2023:
Residential	$	684	$	719		$	—	$	—	$	—	$	1,403
Commercial	558		393			—		—		—		951
Industrial	136		96			—		—		—		232
Other	381		(44)		(a)	—		324		(72)		589
Total electric revenues	$	1,759	$	1,164		$	—	$	324	$	(72)	$	3,175
Residential	$	65	$	—		$	394	$	—	$	—	$	459
Commercial	29		—			102		—		—		131
Industrial	3		—			9		—		—		12
Other	8		—			38		—		(1)		45
Total natural gas revenues	$	105	$	—		$	543	$	—	$	(1)	$	647
Total revenues(b)	$	1,864	$	1,164		$	543	$	324	$	(73)	$	3,822

(a)Includes over-recoveries of various riders.

(b)The following table presents increases/(decreases) in revenues from alternative revenue programs and other revenues not from contracts with customers for the three and six months ended June 30, 2024 and 2023:

	Ameren Missouri			Ameren Illinois Electric Distribution		Ameren Illinois Natural Gas		Ameren Transmission		Ameren
Three Months 2024:
Revenues from alternative revenue programs	$	(1)		$	22	$	—	$	4	$	25
Other revenues not from contracts with customers	1			1		1		—		3
Three Months 2023:
Revenues from alternative revenue programs	$	—		$	60	$	9	$	5	$	74
Other revenues not from contracts with customers	(2)		(a)	2		1		—		1		(a)
Six Months 2024:
Revenues from alternative revenue programs	$	(7)		$	61	$	19	$	13	$	86
Other revenues not from contracts with customers	2			3		2		—		7
Six Months 2023:
Revenues from alternative revenue programs	$	(2)		$	124	$	37	$	13	$	172
Other revenues not from contracts with customers	(8)		(a)	4		2		—		(2)		(a)

(a)Includes net realized losses on derivative power contracts.

Ameren Illinois

	Ameren Illinois Electric Distribution			Ameren Illinois Natural Gas		Ameren Illinois Transmission		Intersegment Eliminations		Ameren Illinois
Three Months 2024:
Residential	$	311		$	102	$	—	$	—	$	413
Commercial	163			24		—		—		187
Industrial	47			1		—		—		48
Other	(12)		(a)	21		136		(27)		118
Total revenues(b)	$	509		$	148	$	136	$	(27)	$	766
Three Months 2023:
Residential	$	337		$	98	$	—	$	—	$	435
Commercial	193			25		—		—		218
Industrial	48			2		—		—		50
Other	(38)		(a)	27		113		(26)		76
Total revenues(b)	$	540		$	152	$	113	$	(26)	$	779
Six Months 2024:
Residential	$	608		$	389	$	—	$	—	$	997
Commercial	328			92		—		—		420
Industrial	92			5		—		—		97
Other	(13)		(a)	53		267		(55)		252
Total revenues(b)	$	1,015		$	539	$	267	$	(55)	$	1,766
Six Months 2023:
Residential	$	719		$	394	$	—	$	—	$	1,113
Commercial	393			102		—		—		495
Industrial	96			9		—		—		105
Other	(44)		(a)	38		227		(54)		167
Total revenues(b)	$	1,164		$	543	$	227	$	(54)	$	1,880

(a)Includes over-recoveries of various riders.

(b)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 three and six months ended June 30, 2024 and 2023:

	Ameren Illinois Electric Distribution		Ameren Illinois Natural Gas		Ameren Illinois Transmission		Ameren Illinois
Three Months 2024:
Revenues from alternative revenue programs	$	22	$	—	$	2	$	24
Other revenues not from contracts with customers	1		1		—		2
Three Months 2023:
Revenues from alternative revenue programs	$	60	$	9	$	3	$	72
Other revenues not from contracts with customers	2		1		—		3
Six Months 2024:
Revenues from alternative revenue programs	$	61	$	19	$	10	$	90
Other revenues not from contracts with customers	3		2		—		5
Six Months 2023:
Revenues from alternative revenue programs	$	124	$	37	$	10	$	171
Other revenues not from contracts with customers	4		2		—		6

XML

Insider Trading Arrangements

3 Months Ended

6 Months Ended

Jun. 30, 2024

shares

Jun. 30, 2024

shares

Trading Arrangements, by Individual

Non-Rule 10b5-1 Arrangement Adopted

false

Rule 10b5-1 Arrangement Terminated

false

Non-Rule 10b5-1 Arrangement Terminated

false

Michael L. Moehn [Member]

Trading Arrangements, by Individual

Material Terms of Trading Arrangement

On May 21, 2024, Michael L. Moehn, Senior Executive Vice President and Chief Financial Officer of Ameren, adopted a Rule 10b5-1 trading arrangement. Mr. Moehn's Rule 10b5-1 trading arrangement provides for the sale of an aggregate 26,000 shares to be sold in four equal quarterly installments between August 2024 and July 2025. Mr. Moehn’s' Rule 10b5-1 trading arrangement will terminate on the earlier of: (i) July 31, 2025; (ii) execution of all trades or expiration of all orders relating to such trades under the Rule 10b5-1 trading arrangement; or (iii) such date as the Rule 10b5-1 trading arrangement is otherwise terminated according to its terms.

Name

Michael L. Moehn

Title

Senior Executive Vice President and Chief Financial Officer of Ameren

Rule 10b5-1 Arrangement Adopted

true

Adoption Date

May 21, 2024

Arrangement Duration

436 days

Aggregate Available

26,000

26,000

Shawn E. Schukar [Member]

Trading Arrangements, by Individual

Material Terms of Trading Arrangement

On May 22, 2024, Shawn E. Schukar, Chairman and President of ATXI, adopted a Rule 10b5-1 trading arrangement. Mr. Schukar's Rule 10b5-1 trading arrangement provides for the sale of 100% of any net shares of Ameren common stock received, after tax withholding, in connection with certain previously awarded restricted stock units and performance share units that will vest upon payment in March 2025 and March 2026. The estimated maximum number of shares to be sold pursuant to the Rule 10b5-1 trading arrangement is 10,170 shares. The actual number of shares sold pursuant to the Rule 10b5-1 trading arrangement will depend on the actual number of shares earned pursuant to the awards, which is generally dependent on the Company's achievement of certain performance measures, the actual dividends paid by the Company during the applicable vesting periods, and Mr. Schukar's continued employment and individual performance during the applicable vesting periods. Mr. Schukar's Rule 10b5-1 trading arrangement will terminate on the earlier of: (i) March 31, 2026; (ii) execution of all trades or expiration of all orders relating to such trades under the Rule 10b5-1 trading arrangement; or (iii) such date as the Rule 10b5-1 trading arrangement is otherwise terminated according to its terms.

Name

Shawn E. Schukar

Title

Chairman and President of ATXI

Rule 10b5-1 Arrangement Adopted

true

Adoption Date

May 22, 2024

Arrangement Duration

678 days

Aggregate Available

10,170

10,170

Mark C. Lindgren [Member]

Trading Arrangements, by Individual

Material Terms of Trading Arrangement

On June 6, 2024, Mark C. Lindgren, Executive Vice President, Corporate Communications, and Chief Human Resources Officer of Ameren Services Company, adopted a Rule 10b5-1 trading arrangement. Mr. Lindgren's Rule 10b5-1 trading arrangement provides for the

sale of 50% of any net shares of Ameren common stock received, after tax withholding, in connection with certain previously awarded restricted stock units and performance share units that will vest upon payment in March 2025 and March 2026. The estimated maximum number of shares to be sold pursuant to the Rule 10b5-1 trading arrangement is 3,841 shares. The actual number of shares sold pursuant to the Rule 10b5-1 trading arrangement will depend on the actual number of shares earned pursuant to the awards, which is generally dependent on the Company's achievement of certain performance measures, the actual dividends paid by the Company during the applicable vesting periods, and Mr. Lindgren's continued employment and individual performance during the applicable vesting periods. Mr. Lindgren's Rule 10b5-1 trading arrangement will terminate on the earlier of: (i) March 31, 2026; (ii) execution of all trades or expiration of all orders relating to such trades under the Rule 10b5-1 trading arrangement; or (iii) such date as the Rule 10b5-1 trading arrangement is otherwise terminated according to its terms.

Name

Mark C. Lindgren

Title

Executive Vice President, Corporate Communications, and Chief Human Resources Officer of Ameren Services Company

Rule 10b5-1 Arrangement Adopted

true

Adoption Date

June 6, 2024

Arrangement Duration

663 days

Aggregate Available

3,841

3,841

XML

Summary Of Significant Accounting Policies (Policies)

6 Months Ended

Jun. 30, 2024

Accounting Policies [Abstract]

Nature of Operations

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 Illinois Company, doing business as Ameren Illinois, operates rate-regulated electric transmission, electric distribution, and natural gas distribution businesses in Illinois.

•ATXI operates a FERC rate-regulated electric transmission business in the MISO.

Consolidation

Ameren’s and Ameren Missouri’s financial statements are prepared on a consolidated basis and therefore include the accounts of their majority-owned subsidiaries. All intercompany transactions have been eliminated. Ameren Missouri’s subsidiaries were created for the ownership of renewable generation projects. Ameren Illinois has 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 statement 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 reporting periods. Actual results could differ from those estimates. The results of operations for an interim period may not give a true indication of results that may be expected for a full year. These financial statements should be read in conjunction with the financial statements and accompanying notes included in the Form 10-K.

Consolidation, Variable Interest Entity, Policy

Variable Interest Entities

As of June 30, 2024, and December 31, 2023, Ameren had unconsolidated variable interests in various equity method investments, primarily to advance clean and resilient energy technologies, totaling $75 million and $73 million, respectively, included in “Other assets” on Ameren’s consolidated balance sheet. Any earnings or losses related to these investments are included in “Other Income, Net” on Ameren’s consolidated statement of income and comprehensive income. Ameren is not the primary beneficiary of these investments because it does not have the power to direct matters that most significantly affect the activities of these variable interest entities. As of June 30, 2024, Ameren’s maximum exposure to loss related to these variable interests is limited to its investment of $75 million plus associated outstanding funding commitments of $12 million.

Life Insurance, Corporate Or Bank Owned

COLI

Ameren and Ameren Illinois have COLI, 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.

Derivatives, Policy

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

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

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

•actual cash outlays for the purchase of these commodities that differ from anticipated cash outlays; and

•actual off-system sales revenues that differ from anticipated revenues.

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.

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. 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. The following disclosures exclude NPNS contracts and other non-derivative commodity contracts that are accounted for under the accrual method of accounting.

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.

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.

Deferred Compensation

Deferred Compensation

At June 30, 2024, and December 31, 2023, the present value of benefits to be paid for deferred compensation obligations was $80 million and $85 million, respectively, which was primarily reflected in “Other deferred credits and liabilities” on Ameren’s consolidated balance sheet.

Revenue from Contract with Customer

Operating Revenues

As of June 30, 2024 and 2023, our remaining performance obligations for contracts with a term greater than one year were immaterial. 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.

See Note 14 – Segment Information for disaggregated revenue information.

Excise Taxes

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.

XML

Rate and Regulatory Matters (Tables)

6 Months Ended

Jun. 30, 2024

Regulated Operations [Abstract]

Schedule of Generation Facilities

The following table provides information with respect to each agreement:

	Agreement type	Facility size	Status of MoPSC CCN	Status of FERC approval of acquisition	Anticipated in-service date(a)
Huck Finn Solar Project(b)(c)	Build-transfer	200-MW	Approved February 2023	Received March 2023	Fourth quarter 2024
Boomtown Solar Project(c)(d)	Build-transfer	150-MW	Approved April 2023	Received October 2023	Fourth quarter 2024(e)
Cass County Solar Project(d)	Development-transfer(f)	150-MW	Approved June 2024	Not applicable	Fourth quarter 2024
Vandalia Solar Project(c)(g)	Self-build	50-MW	Approved March 2024	Not applicable	Fourth quarter 2025
Bowling Green Solar Project(c)(g)	Self-build	50-MW	Approved March 2024	Not applicable	First quarter 2026
Split Rail Solar Project(g)	Build-transfer	300-MW	Approved March 2024	Requested July 2024	Mid-2026
Castle Bluff Natural Gas Project	Self-build	800-MW	Filed June 2024	Not applicable	Fourth quarter 2027

(a)Anticipated in-service dates are dependent on the timing of regulatory approvals and construction completion, among other things.

(b)The Huck Finn Solar Project is expected to support Ameren Missouri’s compliance with the state of Missouri’s renewable energy standard. Investments in the project will be eligible for recovery under the RESRAM. Ameren Missouri expects to close on the acquisition of the Huck Finn Solar Project in the fourth quarter of 2024.

(c)These projects collectively represent approximately $0.85 billion of expected capital expenditures.

(d)The Boomtown and Cass County solar projects are expected to support Ameren Missouri’s transition to renewable energy generation and serve customers under the Renewable Solutions Program.

(e)Ameren Missouri expects to close on the acquisition of the Boomtown Solar Project in August 2024.

(f)In June 2024, Ameren Missouri acquired the Cass County Solar Project, which includes solar panels, project design, land rights, and engineering, procurement, and construction agreements, for approximately $250 million and took over construction management of the project.

(g)These solar projects are expected to support Ameren Missouri’s transition to renewable energy generation.

Schedule of MYRP details

The following table presents the approved revenue requirements and average annual rate base in the ICC’s June 2024 rehearing order, as well as the proposed revenue requirements and average annual rate base in Ameren Illinois’ July 2024 revised MYRP and the ICC staff’s July 2024 revised MYRP recommendation:

Year	Revenue Requirement (in millions)	Average Annual Rate Base (in billions)
ICC’s June 2024 Rehearing Order(a):
2024	$1,196	$4.0
2025	$1,282	$4.3
2026	$1,350	$4.5
2027	$1,397	$4.7
Ameren Illinois’ July 2024 Revised MYRP(a):
2024	$1,215	$4.3
2025	$1,300	$4.5
2026	$1,386	$4.8
2027	$1,446	$5.0
ICC Staff’s July 2024 Revised MYRP(a):
2024	$1,201	$4.2
2025	$1,281	$4.4
2026	$1,361	$4.6
2027	$1,414	$4.8

(a)Based on an allowed ROE of 8.72% and a capital structure composed of 50% common equity. The ROE is under appeal, as discussed above.

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Short-Term Debt and Liquidity (Tables)

6 Months Ended

Jun. 30, 2024

Debt Disclosure [Abstract]

Schedule of Short-term Debt

The following table presents commercial paper outstanding, net of issuance discounts, as of June 30, 2024, and December 31, 2023. There were no borrowings outstanding under the Credit Agreements as of June 30, 2024, or December 31, 2023.

	June 30, 2024		December 31, 2023
Ameren (parent)	$	301	$	—
Ameren Missouri	390		170
Ameren Illinois	—		366
Ameren consolidated	$	691	$	536

The following table summarizes the activity and relevant interest rates for Ameren (parent)’s, Ameren Missouri’s, and Ameren Illinois’ commercial paper issuances and borrowings under the Credit Agreements in the aggregate for the six months ended June 30, 2024 and 2023:

	Ameren (parent)			Ameren Missouri			Ameren Illinois			Ameren Consolidated
2024
Average daily amount outstanding	$	84		$	109		$	385		$	578
Weighted-average interest rate	5.55		%	5.53		%	5.57		%	5.56		%
Peak amount outstanding during period(a)	$	301		$	509		$	694		$	1,084
Peak interest rate	5.60		%	5.68		%	5.68		%	5.68		%
2023
Average daily amount outstanding	$	595		$	343		$	230		$	1,168
Weighted-average interest rate	5.14		%	5.04		%	5.10		%	5.10		%
Peak amount outstanding during period(a)	$	841		$	592		$	450		$	1,381
Peak interest rate	5.55		%	5.55		%	5.60		%	5.60		%

(a)The timing of peak outstanding commercial paper issuances and borrowings under the Credit Agreements varies by company. Therefore, the sum of individual company peak amounts may not equal the Ameren consolidated peak amount for the period.

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Other Income, Net (Tables)

6 Months Ended

Jun. 30, 2024

Other Nonoperating Income (Expense) [Abstract]

Other Income And Expenses

The following table presents the components of “Other Income, Net” in the Ameren Companies’ statements of income for the three and six months ended June 30, 2024 and 2023:

	Three Months				Six Months
	2024		2023		2024		2023
Ameren:
Allowance for equity funds used during construction	$	16	$	14	$	25	$	23
Other interest income	13		9		21		17
Non-service cost components of net periodic benefit income(a)	76		63		152		127
Miscellaneous income	4		2		6		4
Earnings related to equity method investments	1		—		1		2
Donations	(2)		(2)		(4)		(4)
Miscellaneous expense	(5)		(4)		(9)		(9)
Total Other Income, Net	$	103	$	82	$	192	$	160
Ameren Missouri:
Allowance for equity funds used during construction	$	14	$	8	$	23	$	12
Other interest income	3		2		5		6
Non-service cost components of net periodic benefit income(a)	35		14		69		28
Miscellaneous income	—		1		2		2
Donations	(1)		(1)		(2)		(2)
Miscellaneous expense	(2)		(2)		(4)		(5)
Total Other Income, Net	$	49	$	22	$	93	$	41
Ameren Illinois:
Allowance for equity funds used during construction	$	2	$	6	$	2	$	10
Other interest income	9		6		15		10
Non-service cost components of net periodic benefit income	26		31		53		62
Miscellaneous income	2		1		3		2
Donations	(1)		(1)		(2)		(2)
Miscellaneous expense	(1)		(2)		(3)		(4)
Total Other Income, Net	$	37	$	41	$	68	$	78

(a)For the three and six months ended June 30, 2024, the non-service cost components of net periodic benefit income were adjusted by amounts deferred of $(11) million and $(20) million, respectively, 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. The deferral was $17 million and $34 million, respectively, for the three and six months ended June 30, 2023. See Note 11 – Retirement Benefits for additional information.

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Derivative Financial Instruments (Tables)

6 Months Ended

Jun. 30, 2024

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Open Gross Derivative Volumes By Commodity Type

The following table presents open gross commodity contract volumes by commodity type for derivative assets and liabilities as of June 30, 2024, and December 31, 2023. As of June 30, 2024, these contracts extended through October 2027, October 2029 and May 2032 for fuel oils, natural gas and power, respectively.

	Quantity (in millions)
	June 30, 2024			December 31, 2023
Commodity	Ameren Missouri	Ameren Illinois	Ameren	Ameren Missouri	Ameren Illinois	Ameren
Fuel oils (in gallons)	20	—	20	17	—	17
Natural gas (in mmbtu)	52	221	273	53	218	271
Power (in MWhs)	—	5	5	—	5	5
Uranium (pounds in thousands)	—	—	—	186	—	186

Derivative Instruments Carrying Value

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 June 30, 2024, and December 31, 2023:

		June 30, 2024						December 31, 2023
	Balance Sheet Location	Ameren Missouri		Ameren Illinois		Ameren			Ameren Missouri		Ameren Illinois		Ameren
Fuel oils	Other current assets	$	2	$	—	$	2		$	2	$	—	$	2
Natural gas	Other current assets	1		3		4			—		—		—
	Other assets	2		1		3			3		3		6
Power	Other current assets	15		—		15			5		—		5
Uranium	Other current assets	—		—		—			9		—		9
	Total assets	$	20	$	4	$	24		$	19	$	3	$	22
Fuel oils	Other current liabilities	$	1	$	—	$	1		$	1	$	—	$	1
	Other deferred credits and liabilities	—		—		—			1		—		1
Natural gas	Other current liabilities	9		33		42			12		45		57
	Other deferred credits and liabilities	8		28		36			10		30		40
Power	Other current liabilities	1		11		12			1		12		13
	Other deferred credits and liabilities	—		50		50			—		56		56
	Total liabilities	$	19	$	122	$	141		$	25	$	143	$	168

Offsetting Assets and Liabilities

The following table provides the recognized gross derivative balances and the net amounts of those derivatives subject to an enforceable master netting arrangement or similar agreement as of June 30, 2024, and December 31, 2023:

			Gross Amounts Not Offset in the Balance Sheet
Commodity Contracts Eligible to be Offset	Gross Amounts Recognized in the Balance Sheet		Derivative Instruments		Cash Collateral Received/Posted(a)		Net Amount
June 30, 2024
Assets:
Ameren Missouri	$	20	$	5	$	—	$	15
Ameren Illinois	4		2		—		2
Ameren	$	24	$	7	$	—	$	17
Liabilities:
Ameren Missouri	$	19	$	5	$	—	$	14
Ameren Illinois	122		2		—		120
Ameren	$	141	$	7	$	—	$	134
December 31, 2023
Assets:
Ameren Missouri	$	19	$	6	$	—	$	13
Ameren Illinois	3		1		—		2
Ameren	$	22	$	7	$	—	$	15
Liabilities:
Ameren Missouri	$	25	$	6	$	—	$	19
Ameren Illinois	143		1		6		136
Ameren	$	168	$	7	$	6	$	155

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

Derivative Instruments With Credit Risk-Related Contingent Features

The following table presents, as of June 30, 2024, 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:

	Aggregate Fair Value of Derivative Liabilities(a)		Cash Collateral Posted		Potential Aggregate Amount of Additional Collateral Required(b)
Ameren Missouri	$	19	$	—	$	13
Ameren Illinois	61		—		59
Ameren	$	80	$	—	$	72

(a)Before consideration of master netting arrangements or similar agreements.

(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.

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Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2024

Fair Value Disclosures [Abstract]

Schedule Of Fair Value Hierarchy Of Assets And Liabilities Measured At Fair Value On Recurring Basis

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 June 30, 2024, and December 31, 2023:

		June 30, 2024									December 31, 2023
		Level 1		Level 2		Level 3		Total			Level 1		Level 2		Level 3		Total
Assets:
Ameren Missouri
	Derivative assets – commodity contracts:
	Fuel oils	$	1	$	—	$	1	$	2		$	2	$	—	$	—	$	2
	Natural gas	—		3		—		3			—		3		—		3
	Power	—		—		15		15			—		—		5		5
	Uranium	—		—		—		—			—		—		9		9
	Total derivative assets – commodity contracts	$	1	$	3	$	16	$	20		$	2	$	3	$	14	$	19
	Nuclear decommissioning trust fund:
	Equity securities:
	U.S. large capitalization	$	842	$	—	$	—	$	842		$	787	$	—	$	—	$	787
	Debt securities:
	U.S. Treasury and agency securities	—		178		—		178			—		150		—		150
	Corporate bonds	—		154		—		154			—		136		—		136
	Other	—		82		—		82			—		68		—		68
	Total nuclear decommissioning trust fund	$	842	$	414	$	—	$	1,256	(a)	$	787	$	354	$	—	$	1,141	(a)
	Total Ameren Missouri	$	843	$	417	$	16	$	1,276		$	789	$	357	$	14	$	1,160
Ameren Illinois
	Derivative assets – commodity contracts:
	Natural gas	—		1		3		4			—		1		2		3
	Total Ameren Illinois	$	—	$	1	$	3	$	4		$	—	$	1	$	2	$	3
Ameren
	Derivative assets – commodity contracts(b)	$	1	$	4	$	19	$	24		$	2	$	4	$	16	$	22
	Nuclear decommissioning trust fund(c)	842		414		—		1,256		(a)	787		354		—		1,141		(a)
	Total Ameren	$	843	$	418	$	19	$	1,280		$	789	$	358	$	16	$	1,163
Liabilities:
Ameren Missouri
	Derivative liabilities – commodity contracts:
	Fuel oils	$	1	$	—	$	—	$	1		$	2	$	—	$	—	$	2
	Natural gas	—		16		1		17			—		19		3		22
	Power	—		—		1		1			—		—		1		1
	Total Ameren Missouri	$	1	$	16	$	2	$	19		$	2	$	19	$	4	$	25
Ameren Illinois
	Derivative liabilities – commodity contracts:
	Natural gas	$	2	$	52	$	7	$	61		$	4	$	60	$	11	$	75
	Power	—		—		61		61			—		—		68		68
	Total Ameren Illinois	$	2	$	52	$	68	$	122		$	4	$	60	$	79	$	143
Ameren
	Derivative liabilities – commodity contracts(b)	$	3	$	68	$	70	$	141		$	6	$	79	$	83	$	168

(a)Balance excludes $10 million and $9 million of cash and cash equivalents, receivables, payables, and accrued income, net, for June 30, 2024, and December 31, 2023, respectively.

(b)See the Ameren Missouri and Ameren Illinois sections of the table for a breakout of the fair value of Ameren’s derivative assets and liabilities by type of commodity.

(c)See the Ameren Missouri section of the table for a breakout of the fair value of Ameren’s nuclear decommissioning trust fund by investment type.

Schedule Of Changes In The Fair Value Of Financial Assets And Liabilities Classified As Level Three In The Fair Value Hierarchy

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 three and six months ended June 30, 2024 and 2023:

	2024						2023
	Ameren Missouri		Ameren Illinois		Ameren		Ameren Missouri		Ameren Illinois		Ameren
For the three months ended June 30:
Beginning balance at April 1	$	2	$	(54)	$	(52)	$	5	$	(52)	$	(47)
Realized and unrealized gains/(losses) included in regulatory assets/liabilities	15		(12)		3		14		(20)		(6)
Settlements	(3)		5		2		(5)		4		(1)
Ending balance at June 30	$	14	$	(61)	$	(47)	$	14	$	(68)	$	(54)
Change in unrealized gains/(losses) related to assets/liabilities held at June 30	$	14	$	(12)	$	2	$	14	$	(20)	$	(6)
For the six months ended June 30:
Beginning balance at January 1	$	4	$	(68)	$	(64)	$	12	$	(33)	$	(21)
Realized and unrealized gains/(losses) included in regulatory assets/liabilities	14		(2)		12		8		(41)		(33)
Settlements	(4)		9		5		(6)		6		—
Ending balance at June 30	$	14	$	(61)	$	(47)	$	14	$	(68)	$	(54)
Change in unrealized gains/(losses) related to assets/liabilities held at June 30	$	14	$	—	$	14	$	14	$	(35)	$	(21)

Fair Value, Assets and Liabilities Measured on Nonrecurring Basis, Valuation Techniques

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 June 30, 2024, and December 31, 2023:

			Fair Value						Weighted Average(b)
	Commodity		Assets		Liabilities	Valuation Technique(s)	Unobservable Input(a)	Range
2024	Power(c)	$	15	$	(62)	Discounted cash flow	Average forward peak and off-peak pricing – forwards/swaps ($/MWh)	33 – 70	43
							Nodal basis ($/MWh)	(10) – (1)	(5)
2023	Power(c)	$	5	$	(69)	Discounted cash flow	Average forward peak and off-peak pricing – forwards/swaps ($/MWh)	31 – 65	43
							Nodal basis ($/MWh)	(8) – (1)	(5)

(a)Generally, significant increases (decreases) in these inputs in isolation would result in a significantly higher (lower) fair value measurement.

(b)Unobservable inputs were weighted by relative fair value.

(c)Valuations use visible forward prices adjusted for nodal-to-hub basis differentials.

Schedule of Financial Assets and Liabilities

The following table sets forth the carrying amount and, by level within the fair value hierarchy, the fair value of long-term debt (including current portion) disclosed, but not recorded, at fair value as of June 30, 2024, and December 31, 2023:

Long-Term Debt (Including Current Portion):	Carrying Amount(a)		Fair Value
			Level 2		Level 3			Total
	June 30, 2024
Ameren	$	17,079	$	14,990	$	460	(b)	$	15,450
Ameren Missouri	6,830		6,069		—			6,069
Ameren Illinois	5,851		5,251		—			5,251
	December 31, 2023
Ameren	$	15,970	$	14,366	$	467	(b)	$	14,833
Ameren Missouri	6,341		5,800		—			5,800
Ameren Illinois	5,232		4,867		—			4,867

(a)Included unamortized debt issuance costs, which were excluded from the fair value measurement, of $124 million, $53 million, and $52 million for Ameren, Ameren Missouri, and Ameren Illinois, respectively, as of June 30, 2024. Included unamortized debt issuance costs, which were excluded from the fair value measurement, of $111 million, $45 million, and $47 million for Ameren, Ameren Missouri, and Ameren Illinois, respectively, as of December 31, 2023.

(b)The Level 3 fair value amount consists of ATXI’s senior unsecured notes.

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Related Party Transactions (Tables)

6 Months Ended

Jun. 30, 2024

Related Party Transactions [Abstract]

Schedule of Affiliate Receivables and Payables

The following table presents the affiliate balances related to income taxes for Ameren Missouri and Ameren Illinois as of June 30, 2024, and December 31, 2023:

	June 30, 2024				December 31, 2023
	Ameren Missouri		Ameren Illinois		Ameren Missouri		Ameren Illinois
Income taxes payable to parent(a)	$	—	$	44	$	—	$	2
Income taxes receivable from parent(b)	54		—		56		22

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

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

Schedule of Related Party Transactions

The following table presents the impact on Ameren Missouri and Ameren Illinois of related-party transactions for the three and six months ended June 30, 2024 and 2023:

				Three Months				Six Months
Agreement	Income Statement Line Item			Ameren Missouri		Ameren Illinois		Ameren Missouri		Ameren Illinois
Ameren Missouri power supply	Operating Revenues	2024	$	(b)	$	(a)	$	(b)	$	(a)
agreements with Ameren Illinois		2023		(b)		(a)		(b)		(a)
Ameren Missouri and Ameren Illinois	Operating Revenues	2024	$	8	$	(b)	$	15	$	(b)
rent and facility services		2023		8		(b)		18		(b)
Ameren Missouri and Ameren Illinois miscellaneous	Operating Revenues	2024	$	1	$	(b)	$	1	$	1
support services		2023		(b)		(b)		(b)		(b)
Total Operating Revenues		2024	$	9	$	(b)	$	16	$	1
		2023		8		(b)		18		(b)
Ameren Illinois power supply	Purchased Power	2024	$	(a)	$	(b)	$	(a)	$	(b)
agreements with Ameren Missouri		2023		(a)		(b)		(a)		(b)
Ameren Missouri and Ameren Illinois	Purchased Power	2024	$	2	$	1	$	4	$	1
transmission services from ATXI		2023		1		(b)		1		(b)
Total Purchased Power		2024	$	2	$	1	$	4	$	1
		2023		1		(b)		1		(b)
Ameren Missouri and Ameren Illinois	Other Operations and Maintenance	2024	$	(b)	$	(b)	$	(b)	$	(b)
rent and facility services		2023		(b)		(b)		(b)		2
Ameren Services support services	Other Operations and Maintenance	2024	$	43	$	40	$	81	$	77
agreement		2023		35		33		70		68
Total Other Operations and		2024	$	43	$	40	$	81	$	77
Maintenance		2023		35		33		70		70
Money pool interest	(Interest Charges)/Other Income, Net	2024	$	(b)	$	(b)	$	(3)	$	(2)
		2023		(b)		(b)		(b)		(b)

(a)Not applicable.

(b)Amount less than $1 million.

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Callaway Energy Center (Tables)

6 Months Ended

Jun. 30, 2024

Nuclear Waste Matters [Abstract]

Schedule of Insurance Coverage at Callaway Energy Center

The following table presents insurance coverage at Ameren Missouri’s Callaway Energy Center at April 1, 2024:

Type and Source of Coverage	Most Recent Renewal Date	Maximum Coverages			Maximum Assessments for Single Incidents
Public liability and nuclear worker liability:
American Nuclear Insurers	January 1, 2024	$	500		$	—
Pool participation	(a)	15,763		(a)	166		(b)
		$	16,263	(c)	$	166
Property damage:
NEIL and EMANI	April 1, 2024	$	3,200	(d)	$	28	(e)
Accidental outage:
NEIL	April 1, 2024	$	490	(f)	$	11	(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 $500 million in the event of an incident at any licensed United States commercial reactor, payable at $24.7 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 power reactors.

(d)NEIL provides $2.7 billion in property damage, stabilization, decontamination, and premature decommissioning insurance for radiation events and $0.7 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)Accidental outage insurance provides for lost sales 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 $291 million.

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Retirement Benefits (Tables)

6 Months Ended

Jun. 30, 2024

Retirement Benefits [Abstract]

Components Of Net Periodic Benefit Cost

The following table presents the components of the net periodic benefit cost (income) incurred for Ameren’s pension and postretirement benefit plans for the three and six months ended June 30, 2024 and 2023:

	Pension Benefits								Postretirement Benefits
	Three Months				Six Months				Three Months				Six Months
	2024		2023		2024		2023		2024		2023		2024		2023
Service cost(a)	$	23	$	23	$	44	$	46	$	3	$	3	$	6	$	6
Non-service cost components:
Interest cost	56		56		111		111		11		12		22		23
Expected return on plan assets(b)	(82)		(84)		(164)		(167)		(23)		(23)		(46)		(46)
Amortization of(b):
Prior service benefit	—		—		—		—		(1)		(1)		(2)		(2)
Actuarial (gain)	(16)		(28)		(33)		(57)		(10)		(12)		(20)		(23)
Total non-service cost components(c)	$	(42)	$	(56)	$	(86)	$	(113)	$	(23)	$	(24)	$	(46)	$	(48)
Net periodic benefit income(d)	$	(19)	$	(33)	$	(42)	$	(67)	$	(20)	$	(21)	$	(40)	$	(42)

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

(b)Prior service benefit is amortized on a straight-line basis over the average future service of active participants benefiting under a plan amendment. Net actuarial gains or losses related to the net benefit obligation subject to amortization are amortized on a straight-line basis over 10 years. The difference between the actual and expected return on plan assets is amortized over 4 years.

(c)Non-service cost components are reflected in “Other Income, Net” on Ameren’s consolidated statement of income. See Note 5 – Other Income, Net for additional information.

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

Summary Of Benefit Plan Costs Incurred

Ameren Missouri and Ameren Illinois are responsible for their respective share of Ameren’s pension and other postretirement costs. The following table presents the respective share of net periodic pension and other postretirement benefit costs (income) incurred for the three and six months ended June 30, 2024 and 2023:

	Pension Benefits								Postretirement Benefits
	Three Months				Six Months				Three Months				Six Months
	2024		2023		2024		2023		2024		2023		2024		2023
Ameren Missouri(a)	$	(10)	$	(17)	$	(22)	$	(35)	$	(7)	$	(7)	$	(14)	$	(15)
Ameren Illinois	(8)		(13)		(17)		(27)		(13)		(14)		(26)		(27)
Other	(1)		(3)		(3)		(5)		—		—		—		—
Ameren(a)	$	(19)	$	(33)	$	(42)	$	(67)	$	(20)	$	(21)	$	(40)	$	(42)

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

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Income Taxes (Tables)

6 Months Ended

Jun. 30, 2024

Income Tax Disclosure [Abstract]

Schedule of Effective Income Tax Rate Reconciliation

The following table presents a reconciliation of the federal statutory corporate income tax rate to the effective income tax rate for the three and six months ended June 30, 2024 and 2023:

	Ameren				Ameren Missouri				Ameren Illinois
	2024		2023		2024		2023		2024		2023
Three Months
Federal statutory corporate income tax rate	21	%	21	%	21	%	21	%	21	%	21	%
Increases (decreases) from:
Amortization of excess deferred taxes(a)	(8)		(7)		(14)		(15)		(4)		(2)
Renewable and other tax credits(b)	(4)		(5)		(8)		(10)		—		—
State tax	5		5		3		3		7		7
Depreciation differences	(1)		—		(1)		—		—		(1)
Effective income tax rate	13	%	14	%	1	%	(1)	%	24	%	25	%
Six Months
Federal statutory corporate income tax rate	21	%	21	%	21	%	21	%	21	%	21	%
Increases (decreases) from:
Amortization of excess deferred taxes(a)	(8)		(8)		(14)		(15)		(4)		(2)
Renewable and other tax credits(b)	(4)		(4)		(8)		(10)		—		—
State tax	5		5		3		3		7		7
Depreciation differences	—		—		—		—		—		(1)
Other permanent items	—		(1)		—		—		—		—
Effective income tax rate	14	%	13	%	2	%	(1)	%	24	%	25	%

(a)Reflects the amortization of amounts resulting from the revaluation of deferred income taxes subject to regulatory ratemaking, which are being refunded to customers. Deferred income taxes are revalued when federal or state income tax rates change, and the offset to the revaluation of deferred income taxes subject to regulatory ratemaking is recorded to a regulatory asset or liability.

(b)The benefit of the credits associated with Missouri renewable energy standard compliance is refunded to customers through the RESRAM.

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Supplemental Information (Tables)

6 Months Ended

Jun. 30, 2024

Supplemental Information [Abstract]

Schedule of Cash and Cash Equivalents Including Restricted Cash

The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the balance sheets and the statements of cash flows at June 30, 2024, and December 31, 2023:

	June 30, 2024						December 31, 2023
	Ameren		Ameren Missouri		Ameren Illinois		Ameren		Ameren Missouri		Ameren Illinois
“Cash and cash equivalents”	$	19	$	—	$	6	$	25	$	—	$	—
Restricted cash included in “Other current assets”	18		7		7		13		5		5
Restricted cash included in “Other assets”	260		—		260		229		—		229
Restricted cash included in “Nuclear decommissioning trust fund”	4		4		—		5		5		—
Total cash, cash equivalents, and restricted cash	$	301	$	11	$	273	$	272	$	10	$	234

Schedule of Accounts, Notes, Loans and Financing Receivable

The following table provides a reconciliation of the beginning and ending amount of the allowance for doubtful accounts for the three and six months ended June 30, 2024 and 2023:

	Three Months				Six Months
	2024		2023		2024		2023
Ameren:
Beginning of period	$	37	$	34	$	30	$	31
Bad debt expense	6		13		16		23
Charged to other accounts(a)	1		1		4		1
Net write-offs	(7)		(9)		(13)		(16)
End of period	$	37	$	39	$	37	$	39
Ameren Missouri:
Beginning of period	$	11	$	12	$	12	$	13
Bad debt expense	4		2		5		4
Net write-offs	(3)		(2)		(5)		(5)
End of period	$	12	$	12	$	12	$	12
Ameren Illinois:(b)
Beginning of period	$	26	$	22	$	18	$	18
Bad debt expense	2		11		11		19
Charged to other accounts(a)	1		1		4		1
Net write-offs	(4)		(7)		(8)		(11)
End of period	$	25	$	27	$	25	$	27

(a)Amounts associated with the allowance for doubtful accounts related to receivables purchased by Ameren Illinois from alternative retail electric suppliers, as required by the Illinois Public Utilities Act.

(b)Ameren Illinois has rate-adjustment mechanisms that allow it to recover the difference between its actual net bad debt write-offs under GAAP, including those associated with receivables purchased from alternative retail electric suppliers, and the amount of net bad debt write-offs included in its base rates. The table above does not include the impact related to the riders.

Schedule of Cash Flow, Supplemental Disclosures

The following table provides noncash financing and investing activity excluded from the statements of cash flows for the six months ended June 30, 2024 and 2023:

	June 30, 2024						June 30, 2023
	Ameren		Ameren Missouri		Ameren Illinois		Ameren		Ameren Missouri		Ameren Illinois
Investing:
Accrued capital expenditures, including nuclear fuel expenditures	$	380	$	232	$	134	$	325	$	132	$	173
Net realized and unrealized gain – nuclear decommissioning trust fund	103		103		—		105		105		—
Return of investment in industrial development revenue bonds(a)	—		—		—		240		240		—
Financing:
Issuance of common stock for stock-based compensation	$	16	$	—	$	—	$	37	$	—	$	—
Issuance of common stock under the DRPlus	7		—		—		7		—		—
Termination of a financing obligation(a)	—		—		—		240		240		—

(a)In January 2023, Ameren Missouri and Audrain County mutually agreed to terminate a financing obligation agreement related to the CT energy center in Audrain County, which was scheduled to expire in December 2023. No cash was exchanged in connection with the termination of the agreement as the $240 million principal amount of the financing obligation due from Ameren Missouri was equal to the amount of bond service payments due to Ameren Missouri.

Asset Retirement Obligation Disclosure

The following table provides a reconciliation of the beginning and ending carrying amount of AROs for the six months ended June 30, 2024:

	Ameren Missouri			Ameren Illinois			Ameren
Balance at December 31, 2023	$	787	(a)	$	4	(b)	$	791	(a)
Liabilities incurred	7		(c)	—			7		(c)
Liabilities settled	(4)			(1)			(5)
Accretion	17		(d)	—			17		(d)
Balance at June 30, 2024	$	807	(a)	$	3	(b)	$	810	(a)

(a)Balance included $19 million in “Other current liabilities” on the balance sheet as of both June 30, 2024, and December 31, 2023.

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

(c)In June 2024, Ameren and Ameren Missouri recorded an ARO related to the decommissioning for the Cass County Solar Project. In addition, as a result of the 2024 CCR Rule, Ameren and Ameren Missouri recorded an immaterial increase to their AROs associated with CCR storage facilities. See Note 9 – Commitments and Contingencies for additional information.

(d)Accretion expense attributable to Ameren Missouri was recorded as a decrease to regulatory liabilities.

Schedule of excise taxes

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 three and six months ended June 30, 2024 and 2023:

	Three Months				Six Months
	2024		2023		2024		2023
Ameren Missouri	$	41	$	39	$	76	$	73
Ameren Illinois	28		26		65		63
Ameren	$	69	$	65	$	141	$	136

Schedule of Earnings Per Share, Basic and Diluted

The following table reconciles the basic weighted-average number of common shares outstanding to the diluted weighted-average number of common shares outstanding for the three and six months ended June 30, 2024 and 2023:

	Three Months		Six Months
	2024	2023	2024	2023
Weighted-average Common Shares Outstanding – Basic	266.7	262.6	266.5	262.4
Assumed settlement of performance share units and restricted stock units	0.1	0.6	0.3	0.8
Weighted-average Common Shares Outstanding – Diluted(a)	266.8	263.2	266.8	263.2

(a)There was an immaterial number of anti-dilutive performance share units excluded from the earnings per diluted share calculations for the three and six months ended June 30, 2024 and 2023. The outstanding forward sale agreements as of June 30, 2024 and 2023, were anti-dilutive for the three and six months ended June 30, 2024 and 2023, and were excluded from the earnings per diluted share calculation as calculated using the treasury stock method. For additional information about the outstanding forward sale agreements, see Note 4 – Long-term Debt and Equity Financings.

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Segment Information (Tables)

6 Months Ended

Jun. 30, 2024

Segment Reporting [Abstract]

Schedule Of Segment Reporting Information By Segment

The following tables present revenues, net income attributable to common shareholders, and capital expenditures by segment at Ameren and Ameren Illinois for the three and six months ended June 30, 2024 and 2023. Ameren, Ameren Missouri, and Ameren Illinois management review segment capital expenditure information rather than any individual or total asset amount. For additional information about our segments, see Note 16 – Segment Information under Part II, Item 8, of the Form 10-K.

Ameren

	Ameren Missouri		Ameren Illinois Electric Distribution		Ameren Illinois Natural Gas		Ameren Transmission			Other		Intersegment Eliminations		Ameren
Three Months 2024:
External revenues	$	879	$	509	$	148	$	157		$	—	$	—	$	1,693
Intersegment revenues	9		—		—		34			—		(43)		—
Net income (loss) attributable to Ameren common shareholders	128		61		6		79		(a)	(16)		—		258
Capital expenditures	638		132		59		175			2		(4)		1,002
Three Months 2023:
External revenues	$	933	$	540	$	152	$	135		$	—	$	—	$	1,760
Intersegment revenues	8		—		—		26			—		(34)		—
Net income (loss) attributable to Ameren common shareholders	102		66		11		72		(a)	(14)		—		237
Capital expenditures	433		180		90		197			2		(11)		891
Six Months 2024:
External revenues	$	1,647	$	1,015	$	539	$	308		$	—	$	—	$	3,509
Intersegment revenues	16		—		—		68			—		(84)		—
Net income (loss) attributable to Ameren common shareholders	153		117		112		151		(a)	(14)		—		519
Capital expenditures	1,104		316		119		341			4		8		1,892
Six Months 2023:
External revenues	$	1,846	$	1,164	$	543	$	269		$	—	$	—	$	3,822
Intersegment revenues	18		—		—		55			—		(73)		—
Net income attributable to Ameren common shareholders	130		127		98		143		(a)	3		—		501
Capital expenditures	914		350		141		410			5		2		1,822

(a)Ameren Transmission earnings reflect 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
Three Months 2024:
External revenues	$	509	$	148	$	109	$	—	$	766
Intersegment revenues	—		—		27		(27)		—
Net income available to common shareholder	61		6		57		—		124
Capital expenditures	132		59		153		—		344
Three Months 2023:
External revenues	$	540	$	152	$	87	$	—	$	779
Intersegment revenues	—		—		26		(26)		—
Net income available to common shareholder	66		11		52		—		129
Capital expenditures	180		90		167		—		437
Six Months 2024:
External revenues	$	1,015	$	539	$	212	$	—	$	1,766
Intersegment revenues	—		—		55		(55)		—
Net income available to common shareholder	117		112		110		—		339
Capital expenditures	316		119		282		—		717
Six Months 2023:
External revenues	$	1,164	$	543	$	173	$	—	$	1,880
Intersegment revenues	—		—		54		(54)		—
Net income available to common shareholder	127		98		102		—		327
Capital expenditures	350		141		353		—		844

Disaggregation of Revenue

The following tables present disaggregated revenues by segment at Ameren and Ameren Illinois for the three and six months ended June 30, 2024 and 2023. 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, off-system sales, and capacity revenues.

Ameren

	Ameren Missouri		Ameren Illinois Electric Distribution			Ameren Illinois Natural Gas		Ameren Transmission		Intersegment Eliminations		Ameren
Three Months 2024:
Residential	$	395	$	311		$	—	$	—	$	—	$	706
Commercial	324		163			—		—		—		487
Industrial	77		47			—		—		—		124
Other	68		(12)		(a)	—		191		(43)		204
Total electric revenues	$	864	$	509		$	—	$	191	$	(43)	$	1,521
Residential	$	13	$	—		$	102	$	—	$	—	$	115
Commercial	5		—			24		—		—		29
Industrial	1		—			1		—		—		2
Other	5		—			21		—		—		26
Total natural gas revenues	$	24	$	—		$	148	$	—	$	—	$	172
Total revenues(b)	$	888	$	509		$	148	$	191	$	(43)	$	1,693

	Ameren Missouri		Ameren Illinois Electric Distribution			Ameren Illinois Natural Gas		Ameren Transmission		Intersegment Eliminations		Ameren
Three Months 2023:
Residential	$	360	$	337		$	—	$	—	$	—	$	697
Commercial	311		193			—		—		—		504
Industrial	75		48			—		—		—		123
Other	172		(38)		(a)	—		161		(34)		261
Total electric revenues	$	918	$	540		$	—	$	161	$	(34)	$	1,585
Residential	$	13	$	—		$	98	$	—	$	—	$	111
Commercial	6		—			25		—		—		31
Industrial	1		—			2		—		—		3
Other	3		—			27		—		—		30
Total natural gas revenues	$	23	$	—		$	152	$	—	$	—	$	175
Total revenues(b)	$	941	$	540		$	152	$	161	$	(34)	$	1,760
Six Months 2024:
Residential	$	736	$	608		$	—	$	—	$	—	$	1,344
Commercial	583		328			—		—		—		911
Industrial	138		92			—		—		—		230
Other	121		(13)		(a)	—		376		(84)		400
Total electric revenues	$	1,578	$	1,015		$	—	$	376	$	(84)	$	2,885
Residential	$	53	$	—		$	389	$	—	$	—	$	442
Commercial	21		—			92		—		—		113
Industrial	3		—			5		—		—		8
Other	8		—			53		—		—		61
Total natural gas revenues	$	85	$	—		$	539	$	—	$	—	$	624
Total revenues(b)	$	1,663	$	1,015		$	539	$	376	$	(84)	$	3,509
Six Months 2023:
Residential	$	684	$	719		$	—	$	—	$	—	$	1,403
Commercial	558		393			—		—		—		951
Industrial	136		96			—		—		—		232
Other	381		(44)		(a)	—		324		(72)		589
Total electric revenues	$	1,759	$	1,164		$	—	$	324	$	(72)	$	3,175
Residential	$	65	$	—		$	394	$	—	$	—	$	459
Commercial	29		—			102		—		—		131
Industrial	3		—			9		—		—		12
Other	8		—			38		—		(1)		45
Total natural gas revenues	$	105	$	—		$	543	$	—	$	(1)	$	647
Total revenues(b)	$	1,864	$	1,164		$	543	$	324	$	(73)	$	3,822

(a)Includes over-recoveries of various riders.

(b)The following table presents increases/(decreases) in revenues from alternative revenue programs and other revenues not from contracts with customers for the three and six months ended June 30, 2024 and 2023:

	Ameren Missouri			Ameren Illinois Electric Distribution		Ameren Illinois Natural Gas		Ameren Transmission		Ameren
Three Months 2024:
Revenues from alternative revenue programs	$	(1)		$	22	$	—	$	4	$	25
Other revenues not from contracts with customers	1			1		1		—		3
Three Months 2023:
Revenues from alternative revenue programs	$	—		$	60	$	9	$	5	$	74
Other revenues not from contracts with customers	(2)		(a)	2		1		—		1		(a)
Six Months 2024:
Revenues from alternative revenue programs	$	(7)		$	61	$	19	$	13	$	86
Other revenues not from contracts with customers	2			3		2		—		7
Six Months 2023:
Revenues from alternative revenue programs	$	(2)		$	124	$	37	$	13	$	172
Other revenues not from contracts with customers	(8)		(a)	4		2		—		(2)		(a)

(a)Includes net realized losses on derivative power contracts.

Ameren Illinois

	Ameren Illinois Electric Distribution			Ameren Illinois Natural Gas		Ameren Illinois Transmission		Intersegment Eliminations		Ameren Illinois
Three Months 2024:
Residential	$	311		$	102	$	—	$	—	$	413
Commercial	163			24		—		—		187
Industrial	47			1		—		—		48
Other	(12)		(a)	21		136		(27)		118
Total revenues(b)	$	509		$	148	$	136	$	(27)	$	766
Three Months 2023:
Residential	$	337		$	98	$	—	$	—	$	435
Commercial	193			25		—		—		218
Industrial	48			2		—		—		50
Other	(38)		(a)	27		113		(26)		76
Total revenues(b)	$	540		$	152	$	113	$	(26)	$	779
Six Months 2024:
Residential	$	608		$	389	$	—	$	—	$	997
Commercial	328			92		—		—		420
Industrial	92			5		—		—		97
Other	(13)		(a)	53		267		(55)		252
Total revenues(b)	$	1,015		$	539	$	267	$	(55)	$	1,766
Six Months 2023:
Residential	$	719		$	394	$	—	$	—	$	1,113
Commercial	393			102		—		—		495
Industrial	96			9		—		—		105
Other	(44)		(a)	38		227		(54)		167
Total revenues(b)	$	1,164		$	543	$	227	$	(54)	$	1,880

(a)Includes over-recoveries of various riders.

(b)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 three and six months ended June 30, 2024 and 2023:

	Ameren Illinois Electric Distribution		Ameren Illinois Natural Gas		Ameren Illinois Transmission		Ameren Illinois
Three Months 2024:
Revenues from alternative revenue programs	$	22	$	—	$	2	$	24
Other revenues not from contracts with customers	1		1		—		2
Three Months 2023:
Revenues from alternative revenue programs	$	60	$	9	$	3	$	72
Other revenues not from contracts with customers	2		1		—		3
Six Months 2024:
Revenues from alternative revenue programs	$	61	$	19	$	10	$	90
Other revenues not from contracts with customers	3		2		—		5
Six Months 2023:
Revenues from alternative revenue programs	$	124	$	37	$	10	$	171
Other revenues not from contracts with customers	4		2		—		6

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Summary of Significant Accounting Policies (Narrative) (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Basis Of Presentation And Significant Accounting Policies [Line Items]
Unconsolidated variable interest	$ 75	$ 73
Cash Surrender Value of Life Insurance	255	248
Corporate owned life insurance, borrowings	103	104
Ameren Illinois Company
Basis Of Presentation And Significant Accounting Policies [Line Items]
Cash Surrender Value of Life Insurance	114	111
Corporate owned life insurance, borrowings	103	$ 104
Partnership Funding Commitment
Basis Of Presentation And Significant Accounting Policies [Line Items]
Outstanding funding commitments	$ 12

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Rate And Regulatory Matters (Narrative-Missouri) (Details) $ in Millions	1 Months Ended	3 Months Ended					6 Months Ended		12 Months Ended
	Nov. 30, 2023 USD ($)	Jun. 30, 2024 MWh	Sep. 30, 2023 MWh	Dec. 31, 2022 MWh	Sep. 30, 2022 MWh	Jun. 30, 2022 MWh	Jun. 30, 2024 USD ($) MWh	Jun. 30, 2023 USD ($)	Dec. 31, 2025 USD ($)
Rate And Regulatory Matters [Line Items]
Capital expenditures							$ 1,892	$ 1,822
Union Electric Company
Rate And Regulatory Matters [Line Items]
Capital expenditures							1,104	$ 914
Cass County Solar Project Purchase Price							250
Union Electric Company | Rush Island Energy Center
Rate And Regulatory Matters [Line Items]
MoPSC Approved Costs to be Securitized							$ 470
Requested Costs to be Securitized	$ 519
Regulatory Asset, Amortization Period	15 years
Union Electric Company | Solar generation facility
Rate And Regulatory Matters [Line Items]
Amount of Megawatts | MWh							500
Capital expenditures							$ 850
Union Electric Company | Electric | Pending Rate Case
Rate And Regulatory Matters [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Amount							$ 446
Public Utilities, Requested Return on Equity, Percentage							10.25%
Public Utilities, Requested Equity Capital Structure, Percentage							52.00%
Rate Base							$ 14,000
Months to complete a rate proceeding							11 months
Union Electric Company | Electric | MEEIA 2024 | Forecast
Rate And Regulatory Matters [Line Items]
Energy efficiency investments in MEEIA 2019 programs									$ 123
Percentage of MEEIA Energy Efficiency Goals Achieved									100.00%
Incentive award if energy efficiency goals are achieved									$ 56
Incentive award if energy efficiency goals are exceeded									$ 14
Union Electric Company | Build-transfer | Solar generation facility
Rate And Regulatory Matters [Line Items]
Amount of Megawatts | MWh			300		200	150
Union Electric Company | Development-transfer | Solar generation facility
Rate And Regulatory Matters [Line Items]
Amount of Megawatts | MWh			150
Union Electric Company | Self-build | Solar generation facility
Rate And Regulatory Matters [Line Items]
Amount of Megawatts | MWh			50	50
Union Electric Company | Self-build | Natural Gas Generation Facility
Rate And Regulatory Matters [Line Items]
Amount of Megawatts | MWh		800

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Rate And Regulatory Matters (Narrative-Illinois) (Details) - USD ($) $ in Millions	1 Months Ended			3 Months Ended	6 Months Ended		12 Months Ended
	Dec. 31, 2023	Nov. 30, 2023	Oct. 31, 2023	Sep. 30, 2024	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2027	Dec. 31, 2026	Dec. 31, 2025	Dec. 31, 2024
Rate And Regulatory Matters [Line Items]
Capital expenditures					$ 1,892	$ 1,822
Ameren Illinois Company
Rate And Regulatory Matters [Line Items]
Capital expenditures					717	$ 844
Ameren Illinois Company | Natural gas
Rate And Regulatory Matters [Line Items]
Public Utilities, Requested Equity Capital Structure, Percentage	52.00%
Public Utilities, Requested Return on Equity, Percentage	9.89%
IETL | Ameren Illinois Company | Electric Distribution | Forecast
Rate And Regulatory Matters [Line Items]
Approved return on equity percentage							8.72%	8.72%	8.72%	8.72%
Multi-year rate plan rehearing approved revenue requirement							$ 1,397	$ 1,350	$ 1,282	$ 1,196
Approved rate base							4,700	4,500	4,300	4,000
Revised multi-year rate plan requested revenue requirement							1,446	1,386	1,300	1,215
Revised multi-year rate plan requested rate base							5,000	4,800	4,500	4,300
ICC staff revised multi-year rate plan recommended revenue requirement							1,414	1,361	1,281	1,201
ICC staff revised multi-year rate plan recommended rate base							$ 4,800	$ 4,600	$ 4,400	$ 4,200
Public Utilities, Approved Equity Capital Structure, Percentage							50.00%	50.00%	50.00%	50.00%
Public Utilities, Approved Rate Increase (Decrease), Amount										$ 285
Public Utilities, Requested Rate Increase (Decrease), Amount										334
ICC staff recommended rate increase										$ 302
Pending Rate Case | Ameren Illinois Company | Electric Distribution
Rate And Regulatory Matters [Line Items]
ICC staff recommended rate increase					157
Pending Rate Case | Ameren Illinois Company | Electric Distribution | Subsequent Event
Rate And Regulatory Matters [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Amount				$ 158
Public Utilities, Requested Equity Capital Structure, Percentage				50.00%
Pending Rate Case | Ameren Illinois Company | Electric Energy-Efficiency
Rate And Regulatory Matters [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Amount					$ 26
Pending Rate Case | Ameren Illinois Company | Natural gas
Rate And Regulatory Matters [Line Items]
Capital expenditures			$ 53
Over-Recovery Challenged by the Attorney General			$ 3
Final Rate Order | Ameren Illinois Company | Natural gas
Rate And Regulatory Matters [Line Items]
Approved return on equity percentage		9.44%
Approved rate base		$ 2,850
Public Utilities, Approved Equity Capital Structure, Percentage		50.00%
Public Utilities, Requested Rate Increase (Decrease), Amount		$ 112
Capital expenditures	$ 93	$ 93

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Rate And Regulatory Matters (Narrative-Federal) (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		6 Months Ended
	May 31, 2020	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Rate And Regulatory Matters [Line Items]
ROE Change				0.50%
Revenues		$ 1,693	$ 1,760	$ 3,509	$ 3,822
Ameren Illinois Company
Rate And Regulatory Matters [Line Items]
Revenues		$ 766	$ 779	1,766	$ 1,880
Midwest Independent Transmission System Operator, Inc
Rate And Regulatory Matters [Line Items]
Revenues				21
Midwest Independent Transmission System Operator, Inc | Ameren Illinois Company
Rate And Regulatory Matters [Line Items]
Revenues				$ 15
Midwest Independent Transmission System Operator, Inc | Final Rate Order
Rate And Regulatory Matters [Line Items]
Approved return on equity percentage	10.02%

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Short-Term Debt And Liquidity (Narrative) (Details) $ in Billions	3 Months Ended		6 Months Ended
	Jun. 30, 2024 USD ($)	Jun. 30, 2023	Jun. 30, 2024 USD ($)	Jun. 30, 2023
Credit Agreements
Short-term Debt [Line Items]
Net Liquidity Available	$ 1.9		$ 1.9
Actual debt-to-capital ratio	0.61		0.61
Utilities
Short-term Debt [Line Items]
Short-term Debt, Weighted Average Interest Rate, over Time	5.51%	5.28%	5.41%	5.04%
Union Electric Company | Missouri Credit Agreement
Short-term Debt [Line Items]
Actual debt-to-capital ratio	0.49		0.49
Ameren Illinois Company | Illinois Credit Agreement
Short-term Debt [Line Items]
Actual debt-to-capital ratio	0.45		0.45

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Short-Term Debt and Liquidity (Short-Term Debt outstanding) (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Short-term Debt [Line Items]
Short-term debt	$ 691	$ 536
Union Electric Company
Short-term Debt [Line Items]
Short-term debt	390	170
Ameren Illinois Company
Short-term Debt [Line Items]
Short-term debt	0	366
Commercial Paper
Short-term Debt [Line Items]
Short-term debt	691	536
Commercial Paper | Parent Company
Short-term Debt [Line Items]
Short-term debt	301	0
Commercial Paper | Union Electric Company
Short-term Debt [Line Items]
Short-term debt	390	170
Commercial Paper | Ameren Illinois Company
Short-term Debt [Line Items]
Short-term debt	$ 0	$ 366

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Short-Term Debt and Liquidity (Short-Term Debt Activity) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Short-term Debt [Line Items]
Average daily amount outstanding	$ 578	$ 1,168
Weighted-average interest rate	5.56%	5.10%
Short-term Debt, Maximum Amount Outstanding During Period	$ 1,084	$ 1,381
Peak interest rate	5.68%	5.60%
Parent Company
Short-term Debt [Line Items]
Average daily amount outstanding	$ 84	$ 595
Weighted-average interest rate	5.55%	5.14%
Short-term Debt, Maximum Amount Outstanding During Period	$ 301	$ 841
Peak interest rate	5.60%	5.55%
Union Electric Company
Short-term Debt [Line Items]
Average daily amount outstanding	$ 109	$ 343
Weighted-average interest rate	5.53%	5.04%
Short-term Debt, Maximum Amount Outstanding During Period	$ 509	$ 592
Peak interest rate	5.68%	5.55%
Ameren Illinois Company
Short-term Debt [Line Items]
Average daily amount outstanding	$ 385	$ 230
Weighted-average interest rate	5.57%	5.10%
Short-term Debt, Maximum Amount Outstanding During Period	$ 694	$ 450
Peak interest rate	5.68%	5.60%

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Long-Term debt and Equity Financings (Details) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2024 USD ($) shares	Mar. 31, 2024 USD ($) shares	Jun. 30, 2023 USD ($) shares	Jun. 30, 2024 USD ($) $ / shares shares	Jun. 30, 2023 USD ($) shares	Apr. 30, 2024 USD ($)	Jan. 31, 2024 USD ($)
Long-Term Debt And Equity Financings [Line Items]
Shares issued under the DRPlus and 401(k) plan | shares	0.2		0.1	0.3	0.2
Issuances of common stock				$ 21.0	$ 16.0
Stock Issued During Period, Shares, Other | shares	0.0	0.2	0.0	0.2	0.5
Stock Issued During Period, Value, Other		$ 16.0
Maximum Value Of Shares To Be Issued Under ATM Program	$ 770.0			$ 770.0
Forward Contract Indexed to Issuer's Equity, Basis Spread	75			75
Minimum
Long-Term Debt And Equity Financings [Line Items]
Forward Contract Indexed to Issuer's Equity, Forward Rate Per Share | $ / shares				$ 76.69
Maximum
Long-Term Debt And Equity Financings [Line Items]
Forward Contract Indexed to Issuer's Equity, Forward Rate Per Share | $ / shares				89.31
Weighted Average
Long-Term Debt And Equity Financings [Line Items]
Forward Contract Indexed to Issuer's Equity, Forward Rate Per Share | $ / shares				$ 80.45
Dividend reinvestment and 401 (k) plans
Long-Term Debt And Equity Financings [Line Items]
Issuances of common stock	$ 4.0			$ 14.0
Accrued Proceeds from Issuance of Common Stock				$ 7.0
Forward Sale Agreements Outstanding
Long-Term Debt And Equity Financings [Line Items]
Forward Contract Indexed to Issuer's Equity, Settlement Alternatives, Shares, at Fair Value | shares	2.9			2.9
Forward Contract Indexed to Issuer's Equity, Settlement Alternatives, Cash, at Fair Value	$ 232.0			$ 232.0
Period End Net Cash Settlement Price	29.0			29.0
Period End Net Share Settlement Price	$ 0.4			$ 0.4
Forward Sale Agreement Equity Offering Shares | shares	2.9			2.9
Forward Sale Agreement Gross Sales Price	$ 232.0			$ 232.0
Union Electric Company
Long-Term Debt And Equity Financings [Line Items]
Capital contributions from parent				350.0	$ 0.0
Union Electric Company | Other Paid-in Capital:
Long-Term Debt And Equity Financings [Line Items]
Capital contributions from parent	350.0		$ 0.0	350.0	$ 0.0
Union Electric Company | Secured Debt | First Mortgage Bonds, 5.25%, Due 2054 - $350 Issuance
Long-Term Debt And Equity Financings [Line Items]
Debt Instrument, Face Amount							$ 350.0
Debt Instrument, Interest Rate, Stated Percentage							5.25%
Union Electric Company | Secured Debt | Senior Secured Notes 5.20% Due 2034
Long-Term Debt And Equity Financings [Line Items]
Debt Instrument, Face Amount						$ 500.0
Debt Instrument, Interest Rate, Stated Percentage						5.20%
Union Electric Company | Secured Debt | Senior Secured Notes350 Due2024
Long-Term Debt And Equity Financings [Line Items]
Debt Instrument, Face Amount						$ 350.0
Debt Instrument, Interest Rate, Stated Percentage						3.50%
Ameren Illinois Company | Secured Debt | First Mortgage Bonds, 5.55%, Due 2054 - $625 Issuance
Long-Term Debt And Equity Financings [Line Items]
Debt Instrument, Face Amount	$ 625.0			$ 625.0
Debt Instrument, Interest Rate, Stated Percentage	5.55%			5.55%

XML

Other Income, Net (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Other Nonoperating Income (Expense) [Line Items]
Allowance for equity funds used during construction	$ 16	$ 14	$ 25	$ 23
Other interest income	13	9	21	17
Non-service cost components of net periodic benefit income	76	63	152	127
Miscellaneous income	4	2	6	4
Income (Loss) from Equity Method Investments	1	0	1	2
Donations	(2)	(2)	(4)	(4)
Miscellaneous expense	(5)	(4)	(9)	(9)
Total Other Income, Net	103	82	192	160
Union Electric Company
Other Nonoperating Income (Expense) [Line Items]
Allowance for equity funds used during construction	14	8	23	12
Other interest income	3	2	5	6
Non-service cost components of net periodic benefit income	35	14	69	28
Miscellaneous income	0	1	2	2
Donations	(1)	(1)	(2)	(2)
Miscellaneous expense	(2)	(2)	(4)	(5)
Total Other Income, Net	49	22	93	41
Defined Benefit Plan, Non-service Cost or Income Components - Tracker	(11)	17	(20)	34
Ameren Illinois Company
Other Nonoperating Income (Expense) [Line Items]
Allowance for equity funds used during construction	2	6	2	10
Other interest income	9	6	15	10
Non-service cost components of net periodic benefit income	26	31	53	62
Miscellaneous income	2	1	3	2
Donations	(1)	(1)	(2)	(2)
Miscellaneous expense	(1)	(2)	(3)	(4)
Total Other Income, Net	$ 37	$ 41	$ 68	$ 78

XML

Derivative Financial Instruments (Open Gross Derivative Volumes By Commodity Type) (Detail) lb in Thousands, gal in Millions, MWh in Millions, MMBTU in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2024 MWh MMBTU lb gal	Dec. 31, 2023 MWh MMBTU lb gal
Fuel oils
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Volume | gal	20	17
Natural gas
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure | MMBTU	273	271
Power
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure | MWh	5	5
Uranium
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | lb	0	186
Union Electric Company | Fuel oils
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Volume | gal	20	17
Union Electric Company | Natural gas
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure | MMBTU	52	53
Union Electric Company | Power
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure | MWh	0	0
Union Electric Company | Uranium
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | lb	0	186
Ameren Illinois Company | Fuel oils
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Volume | gal	0	0
Ameren Illinois Company | Natural gas
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure | MMBTU	221	218
Ameren Illinois Company | Power
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure | MWh	5	5
Ameren Illinois Company | Uranium
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | lb	0	0

XML

Derivative Financial Instruments (Derivative Instruments Carrying Value) (Detail) - Not Designated As Hedging Instrument - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Derivative [Line Items]
Derivative Assets	$ 24	$ 22
Derivative Liability	141	168
Fuel oils | Other current assets
Derivative [Line Items]
Derivative Assets	2	2
Fuel oils | Other current liabilities
Derivative [Line Items]
Derivative Liability	1	1
Fuel oils | Other deferred credits and liabilities
Derivative [Line Items]
Derivative Liability	0	1
Natural gas | Other current assets
Derivative [Line Items]
Derivative Assets	4	0
Natural gas | Other assets
Derivative [Line Items]
Derivative Assets	3	6
Natural gas | Other current liabilities
Derivative [Line Items]
Derivative Liability	42	57
Natural gas | Other deferred credits and liabilities
Derivative [Line Items]
Derivative Liability	36	40
Power | Other current assets
Derivative [Line Items]
Derivative Assets	15	5
Power | Other current liabilities
Derivative [Line Items]
Derivative Liability	12	13
Power | Other deferred credits and liabilities
Derivative [Line Items]
Derivative Liability	50	56
Uranium | Other current assets
Derivative [Line Items]
Derivative Assets	0	9
Union Electric Company
Derivative [Line Items]
Derivative Assets	20	19
Derivative Liability	19	25
Union Electric Company | Fuel oils | Other current assets
Derivative [Line Items]
Derivative Assets	2	2
Union Electric Company | Fuel oils | Other current liabilities
Derivative [Line Items]
Derivative Liability	1	1
Union Electric Company | Fuel oils | Other deferred credits and liabilities
Derivative [Line Items]
Derivative Liability	0	1
Union Electric Company | Natural gas | Other current assets
Derivative [Line Items]
Derivative Assets	1	0
Union Electric Company | Natural gas | Other assets
Derivative [Line Items]
Derivative Assets	2	3
Union Electric Company | Natural gas | Other current liabilities
Derivative [Line Items]
Derivative Liability	9	12
Union Electric Company | Natural gas | Other deferred credits and liabilities
Derivative [Line Items]
Derivative Liability	8	10
Union Electric Company | Power | Other current assets
Derivative [Line Items]
Derivative Assets	15	5
Union Electric Company | Power | Other current liabilities
Derivative [Line Items]
Derivative Liability	1	1
Union Electric Company | Power | Other deferred credits and liabilities
Derivative [Line Items]
Derivative Liability	0	0
Union Electric Company | Uranium | Other current assets
Derivative [Line Items]
Derivative Assets	0	9
Ameren Illinois Company
Derivative [Line Items]
Derivative Assets	4	3
Derivative Liability	122	143
Ameren Illinois Company | Fuel oils | Other current assets
Derivative [Line Items]
Derivative Assets	0	0
Ameren Illinois Company | Fuel oils | Other current liabilities
Derivative [Line Items]
Derivative Liability	0	0
Ameren Illinois Company | Fuel oils | Other deferred credits and liabilities
Derivative [Line Items]
Derivative Liability	0	0
Ameren Illinois Company | Natural gas | Other current assets
Derivative [Line Items]
Derivative Assets	3	0
Ameren Illinois Company | Natural gas | Other assets
Derivative [Line Items]
Derivative Assets	1	3
Ameren Illinois Company | Natural gas | Other current liabilities
Derivative [Line Items]
Derivative Liability	33	45
Ameren Illinois Company | Natural gas | Other deferred credits and liabilities
Derivative [Line Items]
Derivative Liability	28	30
Ameren Illinois Company | Power | Other current assets
Derivative [Line Items]
Derivative Assets	0	0
Ameren Illinois Company | Power | Other current liabilities
Derivative [Line Items]
Derivative Liability	11	12
Ameren Illinois Company | Power | Other deferred credits and liabilities
Derivative [Line Items]
Derivative Liability	50	56
Ameren Illinois Company | Uranium | Other current assets
Derivative [Line Items]
Derivative Assets	$ 0	$ 0

XML

Derivative Financial Instruments (Offsetting Assets and Liabilities) (Details) - Not Designated As Hedging Instrument - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Derivative [Line Items]
Gross derivative asset amount recognized on the balance sheet	$ 24	$ 22
Gross derivative instruments not offset in the balance sheet	7	7
Gross cash collateral received not offset in the balance sheet	0	0
Net derivative asset	17	15
Gross derivative liability amount recognized on the balance sheet	141	168
Gross derivative instruments not offset in the balance sheet	7	7
Gross cash collateral posted not offset in the balance sheet	0	6
Net derivative liability	134	155
Union Electric Company
Derivative [Line Items]
Gross derivative asset amount recognized on the balance sheet	20	19
Gross derivative instruments not offset in the balance sheet	5	6
Gross cash collateral received not offset in the balance sheet	0	0
Net derivative asset	15	13
Gross derivative liability amount recognized on the balance sheet	19	25
Gross derivative instruments not offset in the balance sheet	5	6
Gross cash collateral posted not offset in the balance sheet	0	0
Net derivative liability	14	19
Ameren Illinois Company
Derivative [Line Items]
Gross derivative asset amount recognized on the balance sheet	4	3
Gross derivative instruments not offset in the balance sheet	2	1
Gross cash collateral received not offset in the balance sheet	0	0
Net derivative asset	2	2
Gross derivative liability amount recognized on the balance sheet	122	143
Gross derivative instruments not offset in the balance sheet	2	1
Gross cash collateral posted not offset in the balance sheet	0	6
Net derivative liability	$ 120	$ 136

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Derivative Financial Instruments (Derivative Instruments with Credit Risk-Related Contingent Features) (Details) $ in Millions	Jun. 30, 2024 USD ($)
Derivative [Line Items]
Aggregate Fair Value of Derivative Liabilities	$ 80
Cash Collateral Posted	0
Potential Aggregate Amount of Additional Collateral Required	72
Union Electric Company
Derivative [Line Items]
Aggregate Fair Value of Derivative Liabilities	19
Cash Collateral Posted	0
Potential Aggregate Amount of Additional Collateral Required	13
Ameren Illinois Company
Derivative [Line Items]
Aggregate Fair Value of Derivative Liabilities	61
Cash Collateral Posted	0
Potential Aggregate Amount of Additional Collateral Required	$ 59

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Fair Value Measurements (Schedule Of Fair Value Hierarchy Of Assets And Liabilities Measured At Fair Value On Recurring Basis) (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund:	$ 1,256	$ 1,141
Assets fair value	1,280	1,163
Excluded receivables, payables, and accrued income, net	10	9
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund:	842	787
Assets fair value	843	789
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund:	414	354
Assets fair value	418	358
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund:	0	0
Assets fair value	19	16
Commodity Contract
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	24	22
Derivative Liability	141	168
Commodity Contract | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	1	2
Derivative Liability	3	6
Commodity Contract | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	4	4
Derivative Liability	68	79
Commodity Contract | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	19	16
Derivative Liability	70	83
Union Electric Company
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund:	1,256	1,141
Assets fair value	1,276	1,160
Union Electric Company | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund:	842	787
Assets fair value	843	789
Union Electric Company | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund:	414	354
Assets fair value	417	357
Union Electric Company | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund:	0	0
Assets fair value	16	14
Union Electric Company | Commodity Contract
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	20	19
Derivative Liability	19	25
Union Electric Company | Commodity Contract | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	1	2
Derivative Liability	1	2
Union Electric Company | Commodity Contract | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	3	3
Derivative Liability	16	19
Union Electric Company | Commodity Contract | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	16	14
Derivative Liability	2	4
Union Electric Company | Fuel oils | Commodity Contract
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	2	2
Derivative Liability	1	2
Union Electric Company | Fuel oils | Commodity Contract | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	1	2
Derivative Liability	1	2
Union Electric Company | Fuel oils | Commodity Contract | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	0	0
Derivative Liability	0	0
Union Electric Company | Fuel oils | Commodity Contract | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	1	0
Derivative Liability	0	0
Union Electric Company | Natural gas | Commodity Contract
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	3	3
Derivative Liability	17	22
Union Electric Company | Natural gas | Commodity Contract | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	0	0
Derivative Liability	0	0
Union Electric Company | Natural gas | Commodity Contract | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	3	3
Derivative Liability	16	19
Union Electric Company | Natural gas | Commodity Contract | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	0	0
Derivative Liability	1	3
Union Electric Company | Power | Commodity Contract
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	15	5
Derivative Liability	1	1
Union Electric Company | Power | Commodity Contract | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	0	0
Derivative Liability	0	0
Union Electric Company | Power | Commodity Contract | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	0	0
Derivative Liability	0	0
Union Electric Company | Power | Commodity Contract | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	15	5
Derivative Liability	1	1
Union Electric Company | Uranium | Commodity Contract
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	0	9
Union Electric Company | Uranium | Commodity Contract | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	0	0
Union Electric Company | Uranium | Commodity Contract | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	0	0
Union Electric Company | Uranium | Commodity Contract | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	0	9
Union Electric Company | Equity securities: | U.S. large capitalization
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund:	842	787
Union Electric Company | Equity securities: | U.S. large capitalization | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund:	842	787
Union Electric Company | Equity securities: | U.S. large capitalization | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund:	0	0
Union Electric Company | Equity securities: | U.S. large capitalization | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund:	0	0
Union Electric Company | Debt securities: | U.S. Treasury and agency securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund:	178	150
Union Electric Company | Debt securities: | U.S. Treasury and agency securities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund:	0	0
Union Electric Company | Debt securities: | U.S. Treasury and agency securities | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund:	178	150
Union Electric Company | Debt securities: | U.S. Treasury and agency securities | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund:	0	0
Union Electric Company | Debt securities: | Corporate bonds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund:	154	136
Union Electric Company | Debt securities: | Corporate bonds | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund:	0	0
Union Electric Company | Debt securities: | Corporate bonds | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund:	154	136
Union Electric Company | Debt securities: | Corporate bonds | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund:	0	0
Union Electric Company | Debt securities: | Other Debt Securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund:	82	68
Union Electric Company | Debt securities: | Other Debt Securities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund:	0	0
Union Electric Company | Debt securities: | Other Debt Securities | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund:	82	68
Union Electric Company | Debt securities: | Other Debt Securities | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund:	0	0
Ameren Illinois Company
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets fair value	4	3
Ameren Illinois Company | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets fair value	0	0
Ameren Illinois Company | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets fair value	1	1
Ameren Illinois Company | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets fair value	3	2
Ameren Illinois Company | Commodity Contract
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Liability	122	143
Ameren Illinois Company | Commodity Contract | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Liability	2	4
Ameren Illinois Company | Commodity Contract | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Liability	52	60
Ameren Illinois Company | Commodity Contract | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Liability	68	79
Ameren Illinois Company | Natural gas | Commodity Contract
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	4	3
Derivative Liability	61	75
Ameren Illinois Company | Natural gas | Commodity Contract | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	0	0
Derivative Liability	2	4
Ameren Illinois Company | Natural gas | Commodity Contract | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	1	1
Derivative Liability	52	60
Ameren Illinois Company | Natural gas | Commodity Contract | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	3	2
Derivative Liability	7	11
Ameren Illinois Company | Power | Commodity Contract
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Liability	61	68
Ameren Illinois Company | Power | Commodity Contract | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Liability	0	0
Ameren Illinois Company | Power | Commodity Contract | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Liability	0	0
Ameren Illinois Company | Power | Commodity Contract | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Liability	$ 61	$ 68

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Fair Value Measurements (Schedule Of Changes In The Fair Value Of Financial Assets And Liabilities Classified As Level Three In The Fair Value Hierarchy) (Details) - Power - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ (52)	$ (47)	$ (64)	$ (21)
Included in regulatory assets/liabilities	3	(6)	12	(33)
Settlements, assets	2			0
Settlement, liabilities		(1)	5
Change in unrealized gains (losses) related to assets/liabilities held at period end	2	(6)	14	(21)
Ending balance	(47)	(54)	(47)	(54)
Union Electric Company
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	2	5	4	12
Included in regulatory assets/liabilities	15	14	14	8
Settlements, assets				6
Settlement, liabilities	(3)	(5)	(4)
Change in unrealized gains (losses) related to assets/liabilities held at period end	14	14	14	14
Ending balance	14	14	14	14
Ameren Illinois Company
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	(54)	(52)	(68)	(33)
Included in regulatory assets/liabilities	(12)	(20)	(2)	(41)
Settlements, assets	5	4	9
Settlement, liabilities				6
Change in unrealized gains (losses) related to assets/liabilities held at period end	(12)	(20)	0	(35)
Ending balance	$ (61)	$ (68)	$ (61)	$ (68)

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Fair Value Measurements (Schedule Of Valuation Process And Unobservable Inputs) (Details) - Power $ in Millions	Jun. 30, 2024 USD ($) $ / MWh	Dec. 31, 2023 USD ($) $ / MWh
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Derivative Assets | $	$ 15	$ 5
Derivative liabilities | $	$ (62)	$ (69)
Commodity Forward Price | Discounted cash flow | Minimum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Measurement input	33	31
Commodity Forward Price | Discounted cash flow | Maximum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Measurement input	70	65
Commodity Forward Price | Discounted cash flow | Weighted Average
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Measurement input	43	43
Nodal Basis | Discounted cash flow | Minimum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Measurement input	(10)	(8)
Nodal Basis | Discounted cash flow | Maximum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Measurement input	(1)	(1)
Nodal Basis | Discounted cash flow | Weighted Average
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Measurement input	(5)	(5)

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Fair Value Measurements (Schedule Of Carrying Amounts And Estimated Fair Values Of Financial Assets and Liabilities) (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Carrying Amount(a)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-Term Debt, Carrying Amount	$ 17,079	$ 15,970
Debt Issuance Costs, Net	124	111
Carrying Amount(a) | Union Electric Company
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-Term Debt, Carrying Amount	6,830	6,341
Debt Issuance Costs, Net	53	45
Carrying Amount(a) | Ameren Illinois Company
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-Term Debt, Carrying Amount	5,851	5,232
Debt Issuance Costs, Net	52	47
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Fair Value	15,450	14,833
Fair Value | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Fair Value	14,990	14,366
Fair Value | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Fair Value	460	467
Fair Value | Union Electric Company
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Fair Value	6,069	5,800
Fair Value | Union Electric Company | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Fair Value	6,069	5,800
Fair Value | Union Electric Company | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Fair Value	0	0
Fair Value | Ameren Illinois Company
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Fair Value	5,251	4,867
Fair Value | Ameren Illinois Company | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Fair Value	5,251	4,867
Fair Value | Ameren Illinois Company | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Fair Value	$ 0	$ 0

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Related Party Transactions (Narrative) (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Related Party Transaction [Line Items]
Other assets	$ 1,049	$ 921
Union Electric Company
Related Party Transaction [Line Items]
Other assets	194	152
Ameren Illinois Company
Related Party Transaction [Line Items]
Other assets	656	603
Ameren Services Support Services Agreement | Union Electric Company | Related Party
Related Party Transaction [Line Items]
Other assets	22	31
Ameren Services Support Services Agreement | Ameren Illinois Company | Related Party
Related Party Transaction [Line Items]
Other assets	$ 24	$ 34

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Related Party Transactions (Schedule of Affiliate Receivables and Payables) (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Related Party Transaction [Line Items]
Accounts Payable, Related Parties, Current	$ 774	$ 1,136
Accounts Receivable, Related Parties, Current	514	494
Union Electric Company | Related Party
Related Party Transaction [Line Items]
Accounts Payable, Related Parties, Current	58	53
Accounts Receivable, Related Parties, Current	67	72
Union Electric Company | Income taxes payable to parent | Related Party
Related Party Transaction [Line Items]
Accounts Payable, Related Parties, Current	0	0
Union Electric Company | Income taxes receivable from parent | Related Party
Related Party Transaction [Line Items]
Accounts Receivable, Related Parties, Current	54	56
Ameren Illinois Company | Related Party
Related Party Transaction [Line Items]
Accounts Payable, Related Parties, Current	97	52
Accounts Receivable, Related Parties, Current	11	35
Ameren Illinois Company | Income taxes payable to parent | Related Party
Related Party Transaction [Line Items]
Accounts Payable, Related Parties, Current	44	2
Ameren Illinois Company | Income taxes receivable from parent | Related Party
Related Party Transaction [Line Items]
Accounts Receivable, Related Parties, Current	$ 0	$ 22

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Related Party Transactions (Effects of Related-party Transactions on the Statement of Income) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Related Party Transaction [Line Items]
Operating Revenues	$ 1,693	$ 1,760	$ 3,509	$ 3,822
Other operations and maintenance	465	450	935	898
(Interest Charges)/Other Income, Net	(165)	(134)	(319)	(261)
Union Electric Company
Related Party Transaction [Line Items]
Operating Revenues	888	941	1,663	1,864
Other operations and maintenance	247	237	501	476
(Interest Charges)/Other Income, Net	(63)	(52)	(125)	(103)
Union Electric Company | Ameren Missouri Power Supply Agreements with Ameren Illinois | Related Party
Related Party Transaction [Line Items]
Operating Revenues	1	1	1	1
Union Electric Company | Ameren Missouri and Ameren Illinois Rent and Facility Services | Related Party
Related Party Transaction [Line Items]
Operating Revenues	8	8	15	18
Other operations and maintenance	1	1	1	1
Union Electric Company | Ameren Missouri and Ameren Illinois Miscellaneous Support Services | Related Party
Related Party Transaction [Line Items]
Operating Revenues	1	1	1	1
Union Electric Company | Total Related Party Operating Revenues | Related Party
Related Party Transaction [Line Items]
Operating Revenues	9	8	16	18
Union Electric Company | Ameren Missouri and Ameren Illinois Transmission Services from ATXI | Related Party
Related Party Transaction [Line Items]
Purchased Power	2	1	4	1
Union Electric Company | Purchased Power | Related Party
Related Party Transaction [Line Items]
Purchased Power	2	1	4	1
Union Electric Company | Ameren Services Support Services Agreement | Related Party
Related Party Transaction [Line Items]
Other operations and maintenance	43	35	81	70
Union Electric Company | Total Related Party Other Operations and Maintenance | Related Party
Related Party Transaction [Line Items]
Other operations and maintenance	43	35	81	70
Union Electric Company | Money pool interest | Related Party
Related Party Transaction [Line Items]
(Interest Charges)/Other Income, Net	(1)	(1)	(3)	(1)
Ameren Illinois Company
Related Party Transaction [Line Items]
Operating Revenues	766	779	1,766	1,880
Purchased Power	141	192	305	479
Other operations and maintenance	224	201	434	403
(Interest Charges)/Other Income, Net	(60)	(50)	(115)	(97)
Ameren Illinois Company | Ameren Missouri and Ameren Illinois Rent and Facility Services | Related Party
Related Party Transaction [Line Items]
Operating Revenues	1	1	1	1
Other operations and maintenance	1	1	1	2
Ameren Illinois Company | Ameren Missouri and Ameren Illinois Miscellaneous Support Services | Related Party
Related Party Transaction [Line Items]
Operating Revenues	1	1	1	1
Ameren Illinois Company | Total Related Party Operating Revenues | Related Party
Related Party Transaction [Line Items]
Operating Revenues	1	1	1	1
Ameren Illinois Company | Ameren Illinois Power Supply Agreements with Ameren Missouri | Related Party
Related Party Transaction [Line Items]
Purchased Power	1	1	1	1
Ameren Illinois Company | Ameren Missouri and Ameren Illinois Transmission Services from ATXI | Related Party
Related Party Transaction [Line Items]
Purchased Power	1	1	1	1
Ameren Illinois Company | Purchased Power | Related Party
Related Party Transaction [Line Items]
Purchased Power	1	1	1	1
Ameren Illinois Company | Ameren Services Support Services Agreement | Related Party
Related Party Transaction [Line Items]
Other operations and maintenance	40	33	77	68
Ameren Illinois Company | Total Related Party Other Operations and Maintenance | Related Party
Related Party Transaction [Line Items]
Other operations and maintenance	40	33	77	70
Ameren Illinois Company | Money pool interest | Related Party
Related Party Transaction [Line Items]
(Interest Charges)/Other Income, Net	$ (1)	$ (1)	$ (2)	$ (1)

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Commitments And Contingencies (Environmental Matters) (Detail) $ in Millions	Jun. 30, 2024 USD ($) scrubber site	May 30, 2024 USD ($)	Dec. 31, 2023 USD ($)
Loss Contingencies [Line Items]
Asset Retirement Obligation	$ 810		$ 791
Minimum
Loss Contingencies [Line Items]
Estimated capital costs to comply with existing and known federal and state air emissions regulations	90
Maximum
Loss Contingencies [Line Items]
Estimated capital costs to comply with existing and known federal and state air emissions regulations	$ 120
Union Electric Company
Loss Contingencies [Line Items]
Number of Energy Center Scrubbers | scrubber	2
Asset Retirement Obligation	$ 807		787
Union Electric Company | Coal Fired Electric Generation Equipment
Loss Contingencies [Line Items]
Plant To Be Abandoned, Net	508
Union Electric Company | Minimum
Loss Contingencies [Line Items]
Estimated capital costs to comply with existing and known federal and state air emissions regulations	90
Union Electric Company | Maximum
Loss Contingencies [Line Items]
Estimated capital costs to comply with existing and known federal and state air emissions regulations	120
Ameren Illinois Company
Loss Contingencies [Line Items]
Asset Retirement Obligation	3		$ 4
Rush Island Energy Center Additional Mitigation Relief Proposed by Ameren Missouri | Union Electric Company
Loss Contingencies [Line Items]
Estimate of possible loss	20
Accrual for environmental loss contingencies	20
Rush Island Energy Center Additional Mitigation Relief Proposed by Department of Justice | Union Electric Company
Loss Contingencies [Line Items]
Estimate of possible loss		$ 120
Manufactured Gas Plant
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies	45
Manufactured Gas Plant | Ameren Illinois Company
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies	$ 45
Number of remediation sites | site	44
Manufactured Gas Plant | Ameren Illinois Company | Minimum
Loss Contingencies [Line Items]
Estimate of possible loss	$ 45
Manufactured Gas Plant | Ameren Illinois Company | Maximum
Loss Contingencies [Line Items]
Estimate of possible loss	95
New CCR Rules Estimate
Loss Contingencies [Line Items]
Asset Retirement Obligation	42
New CCR Rules Estimate | Union Electric Company
Loss Contingencies [Line Items]
Asset Retirement Obligation	$ 42

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Callaway Energy Center (Insurance Disclosure) (Details) $ in Millions	6 Months Ended
	Jun. 30, 2024 USD ($) yr
Nuclear Waste Matters [Line Items]
Decommissioning Cost	$ 7.0
Frequency of Decommissioning Cost Study	3 years
Number Of Years The Limit Of Liability And The Maximum Potential Annual Payments Are Adjusted	5 years
Number Of Weeks Of Coverage After The First Twelve Weeks Of An Outage | yr	1
Number Of Additional Weeks After Initial Indemnity Coverage For Power Outage | yr	1.365
Public Liability And Nuclear Worker Liability - American Nuclear Insurers
Nuclear Waste Matters [Line Items]
Insurance Aggregate Maximum Coverage	$ 500.0
Insurance Maximum Coverage per Incident	0.0
Public Liability And Nuclear Worker Liability - Pool Participation
Nuclear Waste Matters [Line Items]
Insurance Aggregate Maximum Coverage	15,763.0
Insurance Maximum Coverage per Incident	166.0
Threshold Amount For Retrospective Insurance Assessment For Covered Loss Under Public Liability And Nuclear Worker Liability Insurance Policy	500.0
Maximum Annual Payment Per Incident At Licensed Commercial Nuclear Reactor	24.7
Public Liability
Nuclear Waste Matters [Line Items]
Insurance Aggregate Maximum Coverage	16,263.0
Insurance Maximum Coverage per Incident	166.0
Property Damage - Nuclear Electric Insurance Ltd
Nuclear Waste Matters [Line Items]
Insurance Aggregate Maximum Coverage	3,200.0
Insurance Maximum Coverage per Incident	28.0
Accidental Outage - Nuclear Electric Insurance Ltd
Nuclear Waste Matters [Line Items]
Insurance Aggregate Maximum Coverage	490.0
Insurance Maximum Coverage per Incident	11.0
Amount Of Weekly Indemnity Coverage Commencing Twelve Weeks After Power Outage	4.5
Amount Of Additional Weekly Indemnity Coverage Commencing After Initial Indemnity Coverage	3.6
Amount Of Weekly Indemnity Coverage Thereafter Not Exceeding Policy Limit	490.0
Sub-Limit Of Amount Of Weekly Indemnity Coverage Thereafter Not Exceeding Policy Limit For Non-Nuclear Events	291.0
Radiation Event
Nuclear Waste Matters [Line Items]
Insurance Aggregate Maximum Coverage	2,700.0
Aggregate Nuclear Power Industry Insurance Policy Limit For Losses From Terrorist Attacks Within Twelve Month Period	3,200.0
Non-Radiation Event
Nuclear Waste Matters [Line Items]
Insurance Aggregate Maximum Coverage	700.0
Aggregate Nuclear Power Industry Insurance Policy Limit For Losses From Terrorist Attacks Within Twelve Month Period	1,800.0
Property Damage European Mutual Association for Nuclear Insurance
Nuclear Waste Matters [Line Items]
Insurance Aggregate Maximum Coverage	$ 490.0

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Retirement Benefits (Components Of Net Periodic Benefit Cost) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total non-service cost components	$ (76)	$ (63)	$ (152)	$ (127)
Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost	23	23	44	46
Interest cost	56	56	111	111
Defined Benefit Plan, Expected Return (Loss) on Plan Assets	(82)	(84)	(164)	(167)
Prior service benefit	0	0	0	0
Actuarial (gain)	(16)	(28)	(33)	(57)
Total non-service cost components	(42)	(56)	(86)	(113)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Total	(19)	(33)	$ (42)	(67)
Defined Benefit Plan, Amortization Period of Actuarial Gain (Loss)			10 years
Defined Benefit Plan, Difference Between Actual and Expected Return (Loss) on Plan Assets Amortization Period			4 years
Other Postretirement Benefit Plan, Defined Benefit
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost	3	3	$ 6	6
Interest cost	11	12	22	23
Defined Benefit Plan, Expected Return (Loss) on Plan Assets	(23)	(23)	(46)	(46)
Prior service benefit	(1)	(1)	(2)	(2)
Actuarial (gain)	(10)	(12)	(20)	(23)
Total non-service cost components	(23)	(24)	(46)	(48)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Total	$ (20)	$ (21)	$ (40)	$ (42)
Defined Benefit Plan, Amortization Period of Actuarial Gain (Loss)			10 years
Defined Benefit Plan, Difference Between Actual and Expected Return (Loss) on Plan Assets Amortization Period			4 years

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Retirement Benefits (Summary of Benefit Plan Costs Incurred) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic benefit cost	$ (19)	$ (33)	$ (42)	$ (67)
Pension Plan | Union Electric Company
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic benefit cost	(10)	(17)	(22)	(35)
Pension Plan | Ameren Illinois Company
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic benefit cost	(8)	(13)	(17)	(27)
Pension Plan | Other Affiliated Entities And Intercompany Eliminations
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic benefit cost	(1)	(3)	(3)	(5)
Other Postretirement Benefit Plan, Defined Benefit
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic benefit cost	(20)	(21)	(40)	(42)
Other Postretirement Benefit Plan, Defined Benefit | Union Electric Company
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic benefit cost	(7)	(7)	(14)	(15)
Other Postretirement Benefit Plan, Defined Benefit | Ameren Illinois Company
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic benefit cost	(13)	(14)	(26)	(27)
Other Postretirement Benefit Plan, Defined Benefit | Other Affiliated Entities And Intercompany Eliminations
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic benefit cost	$ 0	$ 0	$ 0	$ 0

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Income Taxes (Schedule of Effective Income Tax Rate Reconciliation) (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Income Taxes [Line Items]
Federal statutory corporate income tax rate	21.00%	21.00%	21.00%	21.00%
Increases (decreases) from:
Amortization of excess deferred taxes	(8.00%)	(7.00%)	(8.00%)	(8.00%)
Renewable and other tax credits	(4.00%)	(5.00%)	(4.00%)	(4.00%)
State tax	5.00%	5.00%	5.00%	5.00%
Depreciation differences	(1.00%)	0.00%	0.00%	0.00%
Other permanent items			0.00%	(1.00%)
Effective income tax rate	13.00%	14.00%	14.00%	13.00%
Union Electric Company
Income Taxes [Line Items]
Federal statutory corporate income tax rate	21.00%	21.00%	21.00%	21.00%
Increases (decreases) from:
Amortization of excess deferred taxes	(14.00%)	(15.00%)	(14.00%)	(15.00%)
Renewable and other tax credits	(8.00%)	(10.00%)	(8.00%)	(10.00%)
State tax	3.00%	3.00%	3.00%	3.00%
Depreciation differences	(1.00%)	0.00%	0.00%	0.00%
Other permanent items			0.00%	0.00%
Effective income tax rate	1.00%	(1.00%)	2.00%	(1.00%)
Ameren Illinois Company
Income Taxes [Line Items]
Federal statutory corporate income tax rate	21.00%	21.00%	21.00%	21.00%
Increases (decreases) from:
Amortization of excess deferred taxes	(4.00%)	(2.00%)	(4.00%)	(2.00%)
Renewable and other tax credits	0.00%	0.00%	0.00%	0.00%
State tax	7.00%	7.00%	7.00%	7.00%
Depreciation differences	0.00%	(1.00%)	0.00%	(1.00%)
Other permanent items			0.00%	0.00%
Effective income tax rate	24.00%	25.00%	24.00%	25.00%

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Supplemental Information (Cash and Cash Equivalents) (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023	Jun. 30, 2023	Dec. 31, 2022
Schedule of Cash and Cash Equivalents Including Restricted Cash [Line Items]
Cash and cash equivalents	$ 19	$ 25
Restricted cash included in “Other current assets”	18	13
Restricted cash included in “Other assets”	260	229
Restricted cash included in “Nuclear decommissioning trust fund”	4	5
Total cash, cash equivalents, and restricted cash	301	272	$ 246	$ 216
Union Electric Company
Schedule of Cash and Cash Equivalents Including Restricted Cash [Line Items]
Cash and cash equivalents	0	0
Restricted cash included in “Other current assets”	7	5
Restricted cash included in “Other assets”	0	0
Restricted cash included in “Nuclear decommissioning trust fund”	4	5
Total cash, cash equivalents, and restricted cash	11	10	8	13
Ameren Illinois Company
Schedule of Cash and Cash Equivalents Including Restricted Cash [Line Items]
Cash and cash equivalents	6	0
Restricted cash included in “Other current assets”	7	5
Restricted cash included in “Other assets”	260	229
Restricted cash included in “Nuclear decommissioning trust fund”	0	0
Total cash, cash equivalents, and restricted cash	$ 273	$ 234	$ 229	$ 191

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Supplemental Information (Allowance for Doubtful Accounts) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Allowance for Doubtful Accounts Receivable [Roll Forward]
Beginning of period	$ 37	$ 34	$ 30	$ 31
Bad debt expense	6	13	16	23
Charged to other accounts	1	1	4	1
Net write-offs	(7)	(9)	(13)	(16)
End of period	37	39	37	39
Payables for purchased receivables	49		49		$ 42
Union Electric Company
Allowance for Doubtful Accounts Receivable [Roll Forward]
Beginning of period	11	12	12	13
Bad debt expense	4	2	5	4
Net write-offs	(3)	(2)	(5)	(5)
End of period	12	12	12	12
Ameren Illinois Company
Allowance for Doubtful Accounts Receivable [Roll Forward]
Beginning of period	26	22	18	18
Bad debt expense	2	11	11	19
Charged to other accounts	1	1	4	1
Net write-offs	(4)	(7)	(8)	(11)
End of period	25	$ 27	25	$ 27
Payables for purchased receivables	$ 49		$ 49		$ 42

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Supplemental Information (Supplemental Cash Flow Information) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Supplemental Cash Flow Information [Line Items]
Accrued capital expenditures, including nuclear fuel expenditures	$ 380	$ 325
Net realized and unrealized gain – nuclear decommissioning trust fund	103	105
Return on investment in industrial development revenue bonds	0	240
Termination of a financing obligation	0	240
Issuance of common stock for stock-based compensation
Supplemental Cash Flow Information [Line Items]
Stock Issued	16	37
Issuance of common stock under the DRPlus
Supplemental Cash Flow Information [Line Items]
Stock Issued	7	7
Union Electric Company
Supplemental Cash Flow Information [Line Items]
Accrued capital expenditures, including nuclear fuel expenditures	232	132
Net realized and unrealized gain – nuclear decommissioning trust fund	103	105
Return on investment in industrial development revenue bonds	0	240
Termination of a financing obligation	0	240
Union Electric Company | Issuance of common stock for stock-based compensation
Supplemental Cash Flow Information [Line Items]
Stock Issued	0	0
Union Electric Company | Issuance of common stock under the DRPlus
Supplemental Cash Flow Information [Line Items]
Stock Issued	0	0
Ameren Illinois Company
Supplemental Cash Flow Information [Line Items]
Accrued capital expenditures, including nuclear fuel expenditures	134	173
Net realized and unrealized gain – nuclear decommissioning trust fund	0	0
Return on investment in industrial development revenue bonds	0	0
Termination of a financing obligation	0	0
Ameren Illinois Company | Issuance of common stock for stock-based compensation
Supplemental Cash Flow Information [Line Items]
Stock Issued	0	0
Ameren Illinois Company | Issuance of common stock under the DRPlus
Supplemental Cash Flow Information [Line Items]
Stock Issued	$ 0	$ 0

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Supplemental Information (Schedule of Asset Retirement Obligations) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2024	Dec. 31, 2023
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset Retirement Obligation, Beginning Balance	$ 791
Liabilities incurred	7
Liabilities settled	(5)
Accretion	17
Asset Retirement Obligation, Ending Balance	810
Other current liabilities	655	$ 501
Union Electric Company
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset Retirement Obligation, Beginning Balance	787
Liabilities incurred	7
Liabilities settled	(4)
Accretion	17
Asset Retirement Obligation, Ending Balance	807
Other current liabilities	234	153
Ameren Illinois Company
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset Retirement Obligation, Beginning Balance	4
Liabilities incurred	0
Liabilities settled	(1)
Accretion	0
Asset Retirement Obligation, Ending Balance	3
Other current liabilities	219	263
Asset Retirement Obligation Balance
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Other current liabilities	19	19
Asset Retirement Obligation Balance | Union Electric Company
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Other current liabilities	$ 19	$ 19

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Supplemental Information (Narrative) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Effective Income Tax Rate Reconciliation, Share-based Compensation, Excess Tax Benefit, Amount	$ 1	$ (6)
Deferred Compensation Liability, Classified, Noncurrent	$ 80		$ 85
Q1 2024 Issuance
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years
Performance Shares | Q1 2024 Issuance
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted (in shares)	359,133
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Granted in Period, Fair Value	$ 21
Stock Issued During Period Percentage Conversion Of Units, Low End	0.00%
Stock Issued During Period Percentage Conversion Of Units, High End	200.00%
Performance Shares | Market performance measures achievement | Q1 2024 Issuance
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted (in shares)	307,816
Performance Shares | Renewable generation and energy storage installation targets | Q1 2024 Issuance
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted (in shares)	51,317
Restricted Stock Units (RSUs) | Q1 2024 Issuance
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted (in shares)	153,887
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Granted in Period, Fair Value	$ 11

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Supplemental Information (Schedule Of Excise Taxes) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Accounting Policies [Line Items]
Excise tax expense	$ 69	$ 65	$ 141	$ 136
Union Electric Company
Accounting Policies [Line Items]
Excise tax expense	41	39	76	73
Ameren Illinois Company
Accounting Policies [Line Items]
Excise tax expense	$ 28	$ 26	$ 65	$ 63

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Supplemental Information (Earnings Per Share) (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Earnings Per Share Reconciliation [Abstract]
Weighted-average Common Shares Outstanding – Basic	266,700,000	262,600,000	266,500,000	262,400,000
Assumed settlement of performance share units and restricted stock units	100,000	600,000	300,000	800,000
Weighted-average Common Shares Outstanding – Diluted	266,800,000	263,200,000	266,800,000	263,200,000
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares)	0	0	0	0

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Segment Information (Schedule Of Segment Reporting Information By Segment) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Segment Reporting Information [Line Items]
Operating Revenues	$ 1,693	$ 1,760	$ 3,509	$ 3,822
Net income (loss) attributable to common shareholders	258	237	519	501
Capital expenditures	1,002	891	1,892	1,822
Union Electric Company
Segment Reporting Information [Line Items]
Operating Revenues	888	941	1,663	1,864
Net Income (Loss)	128	102	153	130
Ameren Illinois Company
Segment Reporting Information [Line Items]
Operating Revenues	766	779	1,766	1,880
Net Income (Loss)	124	129	339	327
Capital expenditures	344	437	717	844
Operating Segments | Union Electric Company
Segment Reporting Information [Line Items]
Operating Revenues	879	933	1,647	1,846
Net Income (Loss)	128	102	153	130
Capital expenditures	638	433	1,104	914
Operating Segments | Ameren Illinois Electric Distribution
Segment Reporting Information [Line Items]
Operating Revenues	509	540	1,015	1,164
Net Income (Loss)	61	66	117	127
Capital expenditures	132	180	316	350
Operating Segments | Ameren Illinois Natural Gas
Segment Reporting Information [Line Items]
Operating Revenues	148	152	539	543
Net Income (Loss)	6	11	112	98
Capital expenditures	59	90	119	141
Operating Segments | Ameren Transmission
Segment Reporting Information [Line Items]
Operating Revenues	157	135	308	269
Net Income (Loss)	79	72	151	143
Capital expenditures	175	197	341	410
Operating Segments | Ameren Illinois Company | Ameren Illinois Electric Distribution
Segment Reporting Information [Line Items]
Operating Revenues	509	540	1,015	1,164
Net Income (Loss)	61	66	117	127
Capital expenditures	132	180	316	350
Operating Segments | Ameren Illinois Company | Ameren Illinois Natural Gas
Segment Reporting Information [Line Items]
Operating Revenues	148	152	539	543
Net Income (Loss)	6	11	112	98
Capital expenditures	59	90	119	141
Operating Segments | Ameren Illinois Company | Ameren Illinois Transmission
Segment Reporting Information [Line Items]
Operating Revenues	109	87	212	173
Net Income (Loss)	57	52	110	102
Capital expenditures	153	167	282	353
Other
Segment Reporting Information [Line Items]
Net Income (Loss)	(16)	(14)	(14)	3
Capital expenditures	2	2	4	5
Intersegment Eliminations
Segment Reporting Information [Line Items]
Intersegment revenues	(43)	(34)	(84)	(73)
Capital expenditures	(4)	(11)	8	2
Intersegment Eliminations | Union Electric Company
Segment Reporting Information [Line Items]
Intersegment revenues	(9)	(8)	(16)	(18)
Intersegment Eliminations | Ameren Illinois Electric Distribution
Segment Reporting Information [Line Items]
Intersegment revenues	0	0	0	0
Intersegment Eliminations | Ameren Illinois Natural Gas
Segment Reporting Information [Line Items]
Intersegment revenues	0	0	0	0
Intersegment Eliminations | Ameren Transmission
Segment Reporting Information [Line Items]
Intersegment revenues	(34)	(26)	(68)	(55)
Intersegment Eliminations | Ameren Illinois Company
Segment Reporting Information [Line Items]
Intersegment revenues	(27)	(26)	(55)	(54)
Intersegment Eliminations | Ameren Illinois Company | Ameren Illinois Electric Distribution
Segment Reporting Information [Line Items]
Intersegment revenues	0	0	0	0
Intersegment Eliminations | Ameren Illinois Company | Ameren Illinois Natural Gas
Segment Reporting Information [Line Items]
Intersegment revenues	0	0	0	0
Intersegment Eliminations | Ameren Illinois Company | Ameren Illinois Transmission
Segment Reporting Information [Line Items]
Intersegment revenues	$ (27)	$ (26)	$ (55)	$ (54)

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Segment Information (Disaggregation of Revenue) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Disaggregation of Revenue [Line Items]
Operating Revenues	$ 1,693	$ 1,760	$ 3,509	$ 3,822
Revenues	1,693	1,760	3,509	3,822
Revenues from alternative revenue programs	25	74	86	172
Other revenues not from contracts with customers	3	1	7	(2)
Union Electric Company
Disaggregation of Revenue [Line Items]
Revenues from alternative revenue programs	(1)	0	(7)	(2)
Other revenues not from contracts with customers	1	(2)	2	(8)
Ameren Illinois Electric Distribution
Disaggregation of Revenue [Line Items]
Revenues from alternative revenue programs	22	60	61	124
Other revenues not from contracts with customers	1	2	3	4
Ameren Illinois Natural Gas
Disaggregation of Revenue [Line Items]
Revenues from alternative revenue programs	0	9	19	37
Other revenues not from contracts with customers	1	1	2	2
Ameren Transmission
Disaggregation of Revenue [Line Items]
Revenues from alternative revenue programs	4	5	13	13
Other revenues not from contracts with customers	0	0	0	0
Electric
Disaggregation of Revenue [Line Items]
Operating Revenues	1,521	1,585	2,885	3,175
Revenues	1,521	1,585	2,885	3,175
Electric | Residential
Disaggregation of Revenue [Line Items]
Operating Revenues	706	697	1,344	1,403
Electric | Commercial
Disaggregation of Revenue [Line Items]
Operating Revenues	487	504	911	951
Electric | Industrial
Disaggregation of Revenue [Line Items]
Operating Revenues	124	123	230	232
Electric | Other
Disaggregation of Revenue [Line Items]
Revenues	204	261	400	589
Natural gas
Disaggregation of Revenue [Line Items]
Operating Revenues	172	175	624	647
Revenues	172	175	624	647
Natural gas | Residential
Disaggregation of Revenue [Line Items]
Operating Revenues	115	111	442	459
Natural gas | Commercial
Disaggregation of Revenue [Line Items]
Operating Revenues	29	31	113	131
Natural gas | Industrial
Disaggregation of Revenue [Line Items]
Operating Revenues	2	3	8	12
Natural gas | Other
Disaggregation of Revenue [Line Items]
Revenues	26	30	61	45
Ameren Illinois Company
Disaggregation of Revenue [Line Items]
Operating Revenues	766	779	1,766	1,880
Revenues	766	779	1,766	1,880
Revenues from alternative revenue programs	24	72	90	171
Other revenues not from contracts with customers	2	3	5	6
Ameren Illinois Company | Residential
Disaggregation of Revenue [Line Items]
Operating Revenues	413	435	997	1,113
Ameren Illinois Company | Commercial
Disaggregation of Revenue [Line Items]
Operating Revenues	187	218	420	495
Ameren Illinois Company | Industrial
Disaggregation of Revenue [Line Items]
Operating Revenues	48	50	97	105
Ameren Illinois Company | Other
Disaggregation of Revenue [Line Items]
Revenues	118	76	252	167
Ameren Illinois Company | Ameren Illinois Electric Distribution
Disaggregation of Revenue [Line Items]
Revenues from alternative revenue programs	22	60	61	124
Other revenues not from contracts with customers	1	2	3	4
Ameren Illinois Company | Ameren Illinois Natural Gas
Disaggregation of Revenue [Line Items]
Revenues from alternative revenue programs	0	9	19	37
Other revenues not from contracts with customers	1	1	2	2
Ameren Illinois Company | Ameren Illinois Transmission
Disaggregation of Revenue [Line Items]
Revenues from alternative revenue programs	2	3	10	10
Other revenues not from contracts with customers	0	0	0	0
Ameren Illinois Company | Electric
Disaggregation of Revenue [Line Items]
Operating Revenues	618	627	1,227	1,337
Ameren Illinois Company | Natural gas
Disaggregation of Revenue [Line Items]
Operating Revenues	148	152	539	543
Operating Segments | Union Electric Company
Disaggregation of Revenue [Line Items]
Operating Revenues	879	933	1,647	1,846
Revenues	888	941	1,663	1,864
Operating Segments | Ameren Illinois Electric Distribution
Disaggregation of Revenue [Line Items]
Operating Revenues	509	540	1,015	1,164
Revenues	509	540	1,015	1,164
Operating Segments | Ameren Illinois Natural Gas
Disaggregation of Revenue [Line Items]
Operating Revenues	148	152	539	543
Revenues	148	152	539	543
Operating Segments | Ameren Transmission
Disaggregation of Revenue [Line Items]
Operating Revenues	157	135	308	269
Revenues	191	161	376	324
Operating Segments | Electric | Union Electric Company
Disaggregation of Revenue [Line Items]
Revenues	864	918	1,578	1,759
Operating Segments | Electric | Union Electric Company | Residential
Disaggregation of Revenue [Line Items]
Operating Revenues	395	360	736	684
Operating Segments | Electric | Union Electric Company | Commercial
Disaggregation of Revenue [Line Items]
Operating Revenues	324	311	583	558
Operating Segments | Electric | Union Electric Company | Industrial
Disaggregation of Revenue [Line Items]
Operating Revenues	77	75	138	136
Operating Segments | Electric | Union Electric Company | Other
Disaggregation of Revenue [Line Items]
Revenues	68	172	121	381
Operating Segments | Electric | Ameren Illinois Electric Distribution
Disaggregation of Revenue [Line Items]
Revenues	509	540	1,015	1,164
Operating Segments | Electric | Ameren Illinois Electric Distribution | Residential
Disaggregation of Revenue [Line Items]
Operating Revenues	311	337	608	719
Operating Segments | Electric | Ameren Illinois Electric Distribution | Commercial
Disaggregation of Revenue [Line Items]
Operating Revenues	163	193	328	393
Operating Segments | Electric | Ameren Illinois Electric Distribution | Industrial
Disaggregation of Revenue [Line Items]
Operating Revenues	47	48	92	96
Operating Segments | Electric | Ameren Illinois Electric Distribution | Other
Disaggregation of Revenue [Line Items]
Revenues	(12)	(38)	(13)	(44)
Operating Segments | Electric | Ameren Illinois Natural Gas
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Operating Segments | Electric | Ameren Illinois Natural Gas | Residential
Disaggregation of Revenue [Line Items]
Operating Revenues	0	0	0	0
Operating Segments | Electric | Ameren Illinois Natural Gas | Commercial
Disaggregation of Revenue [Line Items]
Operating Revenues	0	0	0	0
Operating Segments | Electric | Ameren Illinois Natural Gas | Industrial
Disaggregation of Revenue [Line Items]
Operating Revenues	0	0	0	0
Operating Segments | Electric | Ameren Illinois Natural Gas | Other
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Operating Segments | Electric | Ameren Transmission
Disaggregation of Revenue [Line Items]
Revenues	191	161	376	324
Operating Segments | Electric | Ameren Transmission | Residential
Disaggregation of Revenue [Line Items]
Operating Revenues	0	0	0	0
Operating Segments | Electric | Ameren Transmission | Commercial
Disaggregation of Revenue [Line Items]
Operating Revenues	0	0	0	0
Operating Segments | Electric | Ameren Transmission | Industrial
Disaggregation of Revenue [Line Items]
Operating Revenues	0	0	0	0
Operating Segments | Electric | Ameren Transmission | Other
Disaggregation of Revenue [Line Items]
Revenues	191	161	376	324
Operating Segments | Natural gas | Union Electric Company
Disaggregation of Revenue [Line Items]
Revenues	24	23	85	105
Operating Segments | Natural gas | Union Electric Company | Residential
Disaggregation of Revenue [Line Items]
Operating Revenues	13	13	53	65
Operating Segments | Natural gas | Union Electric Company | Commercial
Disaggregation of Revenue [Line Items]
Operating Revenues	5	6	21	29
Operating Segments | Natural gas | Union Electric Company | Industrial
Disaggregation of Revenue [Line Items]
Operating Revenues	1	1	3	3
Operating Segments | Natural gas | Union Electric Company | Other
Disaggregation of Revenue [Line Items]
Revenues	5	3	8	8
Operating Segments | Natural gas | Ameren Illinois Electric Distribution
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Operating Segments | Natural gas | Ameren Illinois Electric Distribution | Residential
Disaggregation of Revenue [Line Items]
Operating Revenues	0	0	0	0
Operating Segments | Natural gas | Ameren Illinois Electric Distribution | Commercial
Disaggregation of Revenue [Line Items]
Operating Revenues	0	0	0	0
Operating Segments | Natural gas | Ameren Illinois Electric Distribution | Industrial
Disaggregation of Revenue [Line Items]
Operating Revenues	0	0	0	0
Operating Segments | Natural gas | Ameren Illinois Electric Distribution | Other
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Operating Segments | Natural gas | Ameren Illinois Natural Gas
Disaggregation of Revenue [Line Items]
Revenues	148	152	539	543
Operating Segments | Natural gas | Ameren Illinois Natural Gas | Residential
Disaggregation of Revenue [Line Items]
Operating Revenues	102	98	389	394
Operating Segments | Natural gas | Ameren Illinois Natural Gas | Commercial
Disaggregation of Revenue [Line Items]
Operating Revenues	24	25	92	102
Operating Segments | Natural gas | Ameren Illinois Natural Gas | Industrial
Disaggregation of Revenue [Line Items]
Operating Revenues	1	2	5	9
Operating Segments | Natural gas | Ameren Illinois Natural Gas | Other
Disaggregation of Revenue [Line Items]
Revenues	21	27	53	38
Operating Segments | Natural gas | Ameren Transmission
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Operating Segments | Natural gas | Ameren Transmission | Residential
Disaggregation of Revenue [Line Items]
Operating Revenues	0	0	0	0
Operating Segments | Natural gas | Ameren Transmission | Commercial
Disaggregation of Revenue [Line Items]
Operating Revenues	0	0	0	0
Operating Segments | Natural gas | Ameren Transmission | Industrial
Disaggregation of Revenue [Line Items]
Operating Revenues	0	0	0	0
Operating Segments | Natural gas | Ameren Transmission | Other
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Operating Segments | Ameren Illinois Company | Ameren Illinois Electric Distribution
Disaggregation of Revenue [Line Items]
Operating Revenues	509	540	1,015	1,164
Operating Segments | Ameren Illinois Company | Ameren Illinois Natural Gas
Disaggregation of Revenue [Line Items]
Operating Revenues	148	152	539	543
Operating Segments | Ameren Illinois Company | Ameren Illinois Transmission
Disaggregation of Revenue [Line Items]
Operating Revenues	109	87	212	173
Operating Segments | Ameren Illinois Company | Electric | Ameren Illinois Electric Distribution
Disaggregation of Revenue [Line Items]
Revenues	509	540	1,015	1,164
Operating Segments | Ameren Illinois Company | Electric | Ameren Illinois Electric Distribution | Residential
Disaggregation of Revenue [Line Items]
Operating Revenues	311	337	608	719
Operating Segments | Ameren Illinois Company | Electric | Ameren Illinois Electric Distribution | Commercial
Disaggregation of Revenue [Line Items]
Operating Revenues	163	193	328	393
Operating Segments | Ameren Illinois Company | Electric | Ameren Illinois Electric Distribution | Industrial
Disaggregation of Revenue [Line Items]
Operating Revenues	47	48	92	96
Operating Segments | Ameren Illinois Company | Electric | Ameren Illinois Electric Distribution | Other
Disaggregation of Revenue [Line Items]
Revenues	(12)	(38)	(13)	(44)
Operating Segments | Ameren Illinois Company | Electric | Ameren Illinois Transmission
Disaggregation of Revenue [Line Items]
Revenues	136	113	267	227
Operating Segments | Ameren Illinois Company | Electric | Ameren Illinois Transmission | Residential
Disaggregation of Revenue [Line Items]
Operating Revenues	0	0	0	0
Operating Segments | Ameren Illinois Company | Electric | Ameren Illinois Transmission | Commercial
Disaggregation of Revenue [Line Items]
Operating Revenues	0	0	0	0
Operating Segments | Ameren Illinois Company | Electric | Ameren Illinois Transmission | Industrial
Disaggregation of Revenue [Line Items]
Operating Revenues	0	0	0	0
Operating Segments | Ameren Illinois Company | Electric | Ameren Illinois Transmission | Other
Disaggregation of Revenue [Line Items]
Revenues	136	113	267	227
Operating Segments | Ameren Illinois Company | Natural gas | Ameren Illinois Natural Gas
Disaggregation of Revenue [Line Items]
Revenues	148	152	539	543
Operating Segments | Ameren Illinois Company | Natural gas | Ameren Illinois Natural Gas | Residential
Disaggregation of Revenue [Line Items]
Operating Revenues	102	98	389	394
Operating Segments | Ameren Illinois Company | Natural gas | Ameren Illinois Natural Gas | Commercial
Disaggregation of Revenue [Line Items]
Operating Revenues	24	25	92	102
Operating Segments | Ameren Illinois Company | Natural gas | Ameren Illinois Natural Gas | Industrial
Disaggregation of Revenue [Line Items]
Operating Revenues	1	2	5	9
Operating Segments | Ameren Illinois Company | Natural gas | Ameren Illinois Natural Gas | Other
Disaggregation of Revenue [Line Items]
Revenues	21	27	53	38
Intersegment Eliminations
Disaggregation of Revenue [Line Items]
Revenues	(43)	(34)	(84)	(73)
Revenues	(43)	(34)	(84)	(73)
Intersegment Eliminations | Union Electric Company
Disaggregation of Revenue [Line Items]
Revenues	(9)	(8)	(16)	(18)
Intersegment Eliminations | Ameren Illinois Electric Distribution
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Intersegment Eliminations | Ameren Illinois Natural Gas
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Intersegment Eliminations | Ameren Transmission
Disaggregation of Revenue [Line Items]
Revenues	(34)	(26)	(68)	(55)
Intersegment Eliminations | Electric
Disaggregation of Revenue [Line Items]
Revenues	(43)	(34)	(84)	(72)
Intersegment Eliminations | Electric | Residential
Disaggregation of Revenue [Line Items]
Operating Revenues	0	0	0	0
Intersegment Eliminations | Electric | Commercial
Disaggregation of Revenue [Line Items]
Operating Revenues	0	0	0	0
Intersegment Eliminations | Electric | Industrial
Disaggregation of Revenue [Line Items]
Operating Revenues	0	0	0	0
Intersegment Eliminations | Electric | Other
Disaggregation of Revenue [Line Items]
Revenues	(43)	(34)	(84)	(72)
Intersegment Eliminations | Natural gas
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	(1)
Intersegment Eliminations | Natural gas | Residential
Disaggregation of Revenue [Line Items]
Operating Revenues	0	0	0	0
Intersegment Eliminations | Natural gas | Commercial
Disaggregation of Revenue [Line Items]
Operating Revenues	0	0	0	0
Intersegment Eliminations | Natural gas | Industrial
Disaggregation of Revenue [Line Items]
Operating Revenues	0	0	0	0
Intersegment Eliminations | Natural gas | Other
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	(1)
Intersegment Eliminations | Ameren Illinois Company
Disaggregation of Revenue [Line Items]
Revenues	(27)	(26)	(55)	(54)
Revenues	(27)	(26)	(55)	(54)
Intersegment Eliminations | Ameren Illinois Company | Residential
Disaggregation of Revenue [Line Items]
Operating Revenues	0	0	0	0
Intersegment Eliminations | Ameren Illinois Company | Commercial
Disaggregation of Revenue [Line Items]
Operating Revenues	0	0	0	0
Intersegment Eliminations | Ameren Illinois Company | Industrial
Disaggregation of Revenue [Line Items]
Operating Revenues	0	0	0	0
Intersegment Eliminations | Ameren Illinois Company | Other
Disaggregation of Revenue [Line Items]
Revenues	(27)	(26)	(55)	(54)
Intersegment Eliminations | Ameren Illinois Company | Ameren Illinois Electric Distribution
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Intersegment Eliminations | Ameren Illinois Company | Ameren Illinois Natural Gas
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Intersegment Eliminations | Ameren Illinois Company | Ameren Illinois Transmission
Disaggregation of Revenue [Line Items]
Revenues	$ (27)	$ (26)	$ (55)	$ (54)