v3.26.3
Income Taxes
 9 Months Ended
Sep. 30, 2026
Income Tax Disclosure [Abstract]  
Income Taxes INCOME TAXES
The following table presents the principal reasons for the difference between the effective income tax expense and rate and the federal statutory corporate income tax expense and rate for the three and nine months ended September 30, 2026 and 2025:
Three MonthsThree MonthsNine MonthsNine Months
2026202520262025
AmountEffective Tax RateAmountEffective Tax RateAmountEffective Tax RateAmountEffective Tax Rate
Ameren
Federal statutory corporate income tax expense and rate$167 21 %$145 21 %$332 21 %$284 21 %
State and local taxes, net of federal income tax(a)
45 5 33 5 86 5 73 5 
Tax credits
Renewable energy tax credits(b)
(34)(4)(22)(3)(67)(4)(50)(3)
Other(3)(1)(2)(1)(6)(1)(7)(1)
Nontaxable or nondeductible items— — 1 — (4)— (1)— 
Other adjustments
Amortization of excess deferred income taxes(c)
(46)(5)(45)(7)(88)(6)(92)(7)
Revaluation of excess deferred income taxes(d)
— — (48)(7)— — (48)(3)
Depreciation differences(10)(1)(10)(1)(22)(1)(14)(1)
Effective income tax expense and rate$119 15 %$52 7 %$231 14 %$145 11 %
Ameren Missouri
Federal statutory corporate income tax expense and rate$125 21 %$116 21 %$175 21 %$159 21 %
State and local taxes, net of federal income tax(a)
17 3 16 3 23 3 22 3 
Tax credits
Renewable energy tax credits(b)
(55)(9)(42)(7)(76)(8)(55)(7)
Other(3)(1)(2)(1)(5)(2)(6)(1)
Other adjustments
Amortization of excess deferred income taxes(c)
(63)(10)(51)(9)(87)(10)(70)(9)
Depreciation differences(10)(2)(5)(1)(15)(2)(7)(1)
Effective income tax expense (benefit) and rate$11 2 %$32 6 %$15 2 %$43 6 %
Ameren Illinois
Federal statutory corporate income tax expense and rate$42 21 %$35 21 %$157 21 %$138 21 %
State and local taxes, net of federal income tax(a)
15 8 12 7 57 7 48 7 
Nontaxable or nondeductible items— — 2 1 (1)— 2 — 
Other adjustments
Amortization of excess deferred income taxes(c)
(4)(2)(6)(4)(11)(1)(24)(4)
Revaluation of excess deferred income taxes(d)
— — (23)(14)— — (23)(4)
Depreciation differences— — (3)(1)(5)(1)(7)— 
Effective income tax expense and rate$53 27 %$17 10 %$197 26 %$134 20 %
(a)State taxes in Missouri and Illinois made up the majority of the tax effect in this category for Ameren, Ameren Missouri, and Ameren Illinois.
(b)The benefit of the credits associated with Missouri renewable energy standard compliance is refunded to customers through the RESRAM. The benefit of the credits associated with the production and investment tax credit tracker will be refunded to customers based on MoPSC approval in a regulatory rate review.
(c)Reflects the amortization of a regulatory liability resulting from the revaluation of accumulated deferred income taxes subject to regulatory ratemaking, which are being refunded to customers.
(d)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 a 2025 FERC order.