v3.26.3
Supplemental Information (Tables)
 9 Months Ended
Sep. 30, 2026
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 September 30, 2026, and December 31, 2025:
September 30, 2026December 31, 2025
AmerenAmeren
Missouri		Ameren
Illinois		AmerenAmeren
Missouri		Ameren
Illinois
“Cash and cash equivalents”$40 $26 $11 $13 $6 $3 
Restricted cash included in “Other current assets”56 45 6 63 54 5 
Restricted cash included in “Other assets”426 — 426 336 — 336 
Restricted cash included in “Nuclear decommissioning trust fund”3 3 — 8 8 — 
Total cash, cash equivalents, and restricted cash$525 $74 $443 $420 $68 $344 
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 nine months ended September 30, 2026 and 2025:
Three MonthsNine Months
2026202520262025
Ameren:
Beginning of period$45 $39 $39 $30 
Bad debt expense21 18 42 37 
Charged to other accounts(a)
3 2 6 5 
Net write-offs(22)(21)(40)(34)
End of period$47 $38 $47 $38 
Ameren Missouri:
Beginning of period$17 $12 $17 $12 
Bad debt expense7 7 13 11 
Net write-offs(5)(4)(11)(8)
End of period$19 $15 $19 $15 
Ameren Illinois:(b)
Beginning of period$28 $27 $22 $18 
Bad debt expense14 

11 29 26 
Charged to other accounts(a)
3 2 6 5 
Net write-offs(17)(17)(29)(26)
End of period$28 $23 $28 $23 
(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 nine months ended September 30, 2026 and 2025:
September 30, 2026September 30, 2025
AmerenAmeren
Missouri		Ameren
Illinois		AmerenAmeren
Missouri		Ameren
Illinois
Investing:
Accrued capital expenditures, including nuclear fuel expenditures$503 

$312 

$148 $412 $277 $147 
Net realized and unrealized gain – nuclear decommissioning trust fund91 91 — 136 136 — 
Financing:
Issuance of common stock for stock-based compensation$25 $— $— $25 $— $— 
Issuance of common stock under the DRPlus6 — — 7 — — 
Asset Retirement Obligation Disclosure
The following table provides a reconciliation of the beginning and ending carrying amount of AROs for the nine months ended September 30, 2026:
Ameren
Missouri		Ameren
Illinois		Ameren
Balance at December 31, 2025
$849 
(a) 
$5 
(b) 
$854 
(a) 
Liabilities incurred7 — 7 
Liabilities settled(3)(c)(3)
Accretion28 
(d) 
(c)28 
(d) 
Change in estimates(20)— (20)
Balance at September 30, 2026
$861 
(a) 
$5 
(b) 
$866 
(a) 
(a)Balance included $3 million and $5 million in “Other current liabilities” on the balance sheet as of September 30, 2026, and December 31, 2025, respectively.
(b)Included in “Other deferred credits and liabilities” on the balance sheet.
(c)Amount less than $1 million.
(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 nine months ended September 30, 2026 and 2025:
Three MonthsNine Months
2026202520262025
Ameren Missouri$75 $69 $162 $150 
Ameren Illinois34 30 111 104 
Ameren$109 $99 $273 $254 
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 nine months ended September 30, 2026 and 2025:
Three MonthsNine Months
2026202520262025
Weighted-average Common Shares Outstanding – Basic276.8 270.4 276.7 270.2 
Assumed settlement of performance share units and restricted stock units1.1 0.8 1.0 0.9 
Dilutive effect of forward sale agreements1.0 1.0 1.0 0.6 
Weighted-average Common Shares Outstanding – Diluted(a)
278.9 272.2 278.7 271.7 
(a)There was an immaterial number of anti-dilutive performance share units excluded from the earnings per diluted share calculations for the three and nine months ended September 30, 2026 and 2025. Outstanding forward sale agreements as of September 30, 2026 and 2025 that were anti-dilutive for the three and nine months ended September 30, 2026 and 2025 were excluded from earnings per diluted share as calculated using the treasury stock method, including 6.0 million and 12.3 million shares for the three and nine months ended September 30, 2026 and an immaterial number of shares for the three and nine months ended September 30, 2025. For additional information about the outstanding forward sale agreements, see Note 4 – Long-term Debt and Equity Financings.