Income Taxes Income Taxes (Tables)

6 Months Ended

Jun. 30, 2022

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 six months ended June 30, 2022 and 2021:

	Ameren				Ameren Missouri				Ameren Illinois
	2022		2021		2022		2021		2022		2021
Three Months
Federal statutory corporate income tax rate	21	%	21	%	21	%	21	%	21	%	21	%
Increases (decreases) from:
Amortization of deferred investment tax credit	—		—		(1)		(1)		—		—
Amortization of excess deferred taxes(a)	(8)		(9)		(15)		(17)		(2)		(2)
Depreciation differences	—		—		—		1		(1)		1
Other	1		—		—		—		—		—
Renewable and other tax credits(b)	(4)		(4)		(10)		(10)		—		(1)
State tax	5		5		3		3		7		7
Effective income tax rate	15	%	13	%	(2)	%	(3)	%	25	%	26	%
Six Months
Federal statutory corporate income tax rate	21	%	21	%	21	%	21	%	21	%	21	%
Increases (decreases) from:
Amortization of deferred investment tax credit	—		—		(1)		(1)		—		—
Amortization of excess deferred taxes(a)	(8)		(9)		(16)		(17)		(2)		(3)
Depreciation differences	—		—		—		1		—		—
Renewable and other tax credits(b)	(5)		(5)		(10)		(10)		—		—
State tax	5		5		3		3		7		7
Effective income tax rate	13	%	12	%	(3)	%	(3)	%	26	%	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)Includes credits associated with the High Prairie and Atchison renewable energy centers. Ameren Missouri placed the High Prairie Renewable Energy Center in service in December 2020. Additionally, Ameren Missouri placed in service the wind turbines at its Atchison Renewable Energy Center throughout the first half of 2021. The benefit of the credits associated with Missouri renewable energy standard compliance is refunded to customers through the RESRAM.