Income Taxes

3 Months Ended

Mar. 31, 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 months ended March 31, 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)		(8)		(12)		(16)		(4)		(2)
Renewable and other tax credits(b)	(4)		(5)		(8)		(10)		—		—
State tax	6		6		4		4		7		7
Stock-based compensation	1		(1)		—		—		—		—
Other depreciation differences	(1)		—		(1)		—		—		—
Other permanent items	(1)		(1)		—		(3)		—		(1)
Effective income tax rate	14	%	12	%	4	%	(4)	%	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.