XML 66 R33.htm IDEA: XBRL DOCUMENT
v3.25.3

Income Taxes (Tables) | 9 Months Ended
--- | ---
Sep. 30, 2025
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 nine months ended September 30, 2025 and 2024:
| Ameren |  | Ameren Missouri |  | Ameren Illinois |
| 2025 |  | 2024 |  | 2025 |  | 2024 |  | 2025 |  | 2024 |
Three Months |  |  |  |  |  |  |  |  |  |  |  |
Federal statutory corporate income tax rate | 21 | % |  | 21 | % |  | 21 | % |  | 21 | % |  | 21 | % |  | 21 | % |
Increases (decreases) from: |  |  |  |  |  |  |  |  |  |  |  |
Amortization of excess deferred taxes(a) | (7) |  |  | (9) |  |  | (9) |  |  | (15) |  |  | (4) |  |  | (4) |  |
Revaluation of excess deferred income taxes(b) | (7) |  |  | — |  |  | — |  |  | — |  |  | (14) |  |  | — |  |
Amortization of deferred investment tax credit | (1) |  |  | — |  |  | (1) |  |  | — |  |  | — |  |  | — |  |
Renewable and other tax credits(c) | (3) |  |  | (4) |  |  | (7) |  |  | (10) |  |  | — |  |  | — |  |
State tax | 5 |  |  | 4 |  |  | 3 |  |  | 3 |  |  | 7 |  |  | 7 |  |
Depreciation differences | (1) |  |  | — |  |  | (1) |  |  | (1) |  |  | (1) |  |  | — |  |
Other permanent items | — |  |  | (1) |  |  | — |  |  | — |  |  | 1 |  |  | — |  |
Effective income tax rate | 7 | % |  | 11 | % |  | 6 | % |  | (2) | % |  | 10 | % |  | 24 | % |
Nine Months |  |  |  |  |  |  |  |  |  |  |  |
Federal statutory corporate income tax rate | 21 | % |  | 21 | % |  | 21 | % |  | 21 | % |  | 21 | % |  | 21 | % |
Increases (decreases) from: |  |  |  |  |  |  |  |  |  |  |  |
Amortization of excess deferred taxes(a) | (7) |  |  | (8) |  |  | (9) |  |  | (14) |  |  | (4) |  |  | (4) |  |
Revaluation of excess deferred income taxes(b) | (3) |  |  | — |  |  | — |  |  | — |  |  | (4) |  |  | — |  |
Amortization of deferred investment tax credit | (1) |  |  | — |  |  | (1) |  |  | — |  |  | — |  |  | — |  |
Renewable and other tax credits(c) | (3) |  |  | (5) |  |  | (7) |  |  | (10) |  |  | — |  |  | — |  |
State tax | 5 |  |  | 5 |  |  | 3 |  |  | 3 |  |  | 7 |  |  | 7 |  |
Depreciation differences | (1) |  |  | — |  |  | (1) |  |  | (1) |  |  | — |  |  | — |  |
Effective income tax rate | 11 | % |  | 13 | % |  | 6 | % |  | (1) | % |  | 20 | % |  | 24 | % |
(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)In 2024, the IRS issued a series of private letter rulings to another taxpayer, which provided guidance on applying IRS normalization rules to the calculation of tax benefits applicable to the ratemaking treatment related to net operating loss carryforwards. The rulings concluded that, for ratemaking purposes, net operating loss carryforwards should be reflected on a separate company basis and should not be reduced by payments received for the utilization of losses by other affiliates under a tax allocation agreement. In 2025, the FERC issued an order reflecting implementation of the rules for the other taxpayer who had a similar fact pattern as Ameren Illinois and ATXI. Accordingly, in the third quarter of 2025, Ameren and Ameren Illinois decreased income tax expense by $48 million and $23 million, respectively, to reflect the revaluation of excess deferred income tax regulatory liabilities resulting from TCJA for FERC-regulated jurisdictions pursuant to IRS guidance and recent FERC order. (c)The benefit of the renewable credits associated with Missouri renewable energy standard compliance is refunded to customers through the RESRAM. The benefit of the renewable credits associated with the production and investment tax credit tracker will be refunded to customers based on MoPSC approval in a regulatory rate review.

X
- References No definition available. + Details
Name: | us-gaap_IncomeTaxDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the reconciliation using percentage or dollar amounts of the reported amount of income tax expense attributable to continuing operations for the year to the amount of income tax expense that would result from applying domestic federal statutory tax rates to pretax income from continuing operations. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 231 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482663/740-10-55-231 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 12A -Publisher FASB -URI https://asc.fasb.org/1943274/2147482685/740-10-50-12A Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 12 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482685/740-10-50-12 + Details
Name: | us-gaap_ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration