Supplemental Information (Tables)

3 Months Ended

Mar. 31, 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 March 31, 2024, and December 31, 2023:

	March 31, 2024						December 31, 2023
	Ameren		Ameren Missouri		Ameren Illinois		Ameren		Ameren Missouri		Ameren Illinois
“Cash and cash equivalents”	$	85	$	2	$	—	$	25	$	—	$	—
Restricted cash included in “Other current assets”	13		5		6		13		5		5
Restricted cash included in “Other assets”	248		—		248		229		—		229
Restricted cash included in “Nuclear decommissioning trust fund”	9		9		—		5		5		—
Total cash, cash equivalents, and restricted cash	$	355	$	16	$	254	$	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 months ended March 31, 2024 and 2023:

	Three Months
	2024		2023
Ameren:
Beginning of period	$	30	$	31
Bad debt expense	10		10
Charged to other accounts(a)	3		—
Net write-offs	(6)		(7)
End of period	$	37	$	34
Ameren Missouri:
Beginning of period	$	12	$	13
Bad debt expense	1		2
Net write-offs	(2)		(3)
End of period	$	11	$	12
Ameren Illinois:(b)
Beginning of period	$	18	$	18
Bad debt expense	9		8
Charged to other accounts(a)	3		—
Net write-offs	(4)		(4)
End of period	$	26	$	22

(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 three months ended March 31, 2024 and 2023:

	March 31, 2024						March 31, 2023
	Ameren		Ameren Missouri		Ameren Illinois		Ameren		Ameren Missouri		Ameren Illinois
Investing:
Accrued capital expenditures, including nuclear fuel expenditures	$	310	$	169	$	122	$	298	$	153	$	138
Net realized and unrealized gain – nuclear decommissioning trust fund	74		74		—		54		54		—
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 three months ended March 31, 2024:

	Ameren Missouri			Ameren Illinois			Ameren
Balance at December 31, 2023	$	787	(a)	$	4	(b)	$	791	(a)
Liabilities settled	—			(1)			(1)
Accretion	8		(c)	—			8		(c)
Balance at March 31, 2024	$	795	(a)	$	3	(b)	$	798	(a)

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

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

(c)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 months ended March 31, 2024 and 2023:

	Three Months
	2024		2023
Ameren Missouri	$	35	$	34
Ameren Illinois	37		37
Ameren	$	72	$	71

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 months ended March 31, 2024 and 2023:

	Three Months
	2024	2023
Weighted-average Common Shares Outstanding – Basic	266.4	262.2
Assumed settlement of performance share units and restricted stock units	0.4	0.9
Weighted-average Common Shares Outstanding – Diluted(a)	266.8	263.1

(a)There was an immaterial number of anti-dilutive performance share units excluded from the earnings per diluted share calculations for the three months ended March 31, 2024 and 2023. The outstanding forward sale agreements as of March 31, 2024 and 2023, were anti-dilutive for the three months ended March 31, 2024 and 2023, and were excluded from the earnings per diluted share calculation as calculated using the treasury stock method. For additional information about our outstanding forward sale agreements, see Note 4 – Long-term Debt and Equity Financings.