Income Taxes (Tables)

12 Months Ended

Dec. 31, 2019

Income Tax Disclosure [Abstract]

Schedule Of Effective Income Tax Rate Reconciliation

The following table presents the principal reasons for the difference between the effective income tax rate and the federal statutory corporate income tax rate for the years ended December 31, 2019, 2018, and 2017:

	Ameren Missouri		Ameren Illinois		Ameren
2019
Federal statutory corporate income tax rate:	21	%	21	%	21	%
Increases (decreases) from:
Amortization of excess deferred income taxes	(11	)	(4	)	(7	)
Amortization of deferred investment tax credit	(1	)	—		(1	)
State tax	5		7		6
Stock-based compensation	—		—		(1	)
Effective income tax rate	14	%	24	%	18	%
2018
Federal statutory corporate income tax rate:	21	%	21	%	21	%
Increases (decreases) from:
Amortization of excess deferred income taxes	(4	)	(4	)	(4	)
Depreciation differences	—		(1	)	—
Amortization of deferred investment tax credit	(1	)	—		(1	)
State tax	4		7		6
TCJA	1		1		1
Tax credits	(1	)	—		—
Other permanent items	—		—		(1	)
Effective income tax rate	20	%	24	%	22	%
2017
Federal statutory corporate income tax rate:	35	%	35	%	35	%
Increases (decreases) from:
Depreciation differences	1		(1	)	—
Amortization of deferred investment tax credit	(1	)	—		(1	)
State tax	4		6		6
TCJA	6		(1	)	14
Tax credits	(1	)	—		—
Other permanent items	—		(1	)	(2	)
Effective income tax rate	44	%	38	%	52	%

Schedule Of Components Of Income Tax Expense (Benefit)

The following table presents the components of income tax expense for the years ended December 31, 2019, 2018, and 2017:

	Ameren Missouri			Ameren Illinois			Other			Ameren
2019
Current taxes:
Federal	$	65		$	19		$	(88	)	$	(4	)
State	22			11			(14		)	19
Deferred taxes:
Federal	37			66			82			185
State	5			29			25			59
Amortization of excess deferred income taxes	(56		)	(15		)	(1		)	(72		)
Amortization of deferred investment tax credits	(5		)	—			—			(5		)
Total income tax expense	$	68		$	110		$	4		$	182
2018
Current taxes:
Federal	$	104		$	4		$	(118	)	$	(10	)
State	29			6			(12		)	23
Deferred taxes:
Federal	22			75			123			220
State	(2		)	28			23			49
Amortization of excess deferred income taxes	(24		)	(15		)	(1		)	(40		)
Amortization of deferred investment tax credits	(5		)	—			—			(5		)
Total income tax expense	$	124		$	98		$	15		$	237
2017
Current taxes:
Federal	$	149		$	(34	)	$	(110	)	$	5
State	23			29			(20		)	32
Deferred taxes:
Federal	76			185			250			511
State	11			(13		)	36			34
Amortization of deferred investment tax credits	(5		)	(1		)	—			(6		)
Total income tax expense	$	254		$	166		$	156		$	576

Schedule Of Deferred Tax Assets And Liabilities Resulting From Temporary Differences

The following table presents the accumulated deferred income tax assets and liabilities recorded as a result of temporary differences and accumulated deferred investment tax credits at December 31, 2019 and 2018:

	Ameren Missouri			Ameren Illinois			Other			Ameren
2019
Accumulated deferred income taxes, net liability (asset):
Plant-related	$	2,000		$	1,423		$	193		$	3,616
Regulatory assets and liabilities, net	(310		)	(214		)	(24		)	(548		)
Deferred employee benefit costs	(59		)	7			(59		)	(111		)
Tax carryforwards	(25		)	(3		)	(70		)	(98		)
Other	(33		)	11			43			21
Total net accumulated deferred income tax liabilities (assets)	$	1,573		$	1,224		$	83		$	2,880
Accumulated deferred investment tax credits	39			—			—			39
Accumulated deferred income taxes and investment tax credits	$	1,612		$	1,224		$	83		$	2,919
2018
Accumulated deferred income taxes, net liability (asset):
Plant-related	$	2,010		$	1,345		$	179		$	3,534
Regulatory assets and liabilities, net	(343		)	(221		)	(25		)	(589		)
Deferred employee benefit costs	(58		)	(4		)	(64		)	(126		)
Tax carryforwards	(35		)	(26		)	(166		)	(227		)
Other	(40		)	24			47			31
Total net accumulated deferred income tax liabilities (assets)	$	1,534		$	1,118		$	(29	)	$	2,623
Accumulated deferred investment tax credits	42			1			—			43
Accumulated deferred income taxes and investment tax credits	$	1,576		$	1,119		$	(29	)	$	2,666

Schedule Of Net Operating Loss Carryforwards And Tax Credit Carryforwards

The following table presents the components of accumulated deferred income tax assets relating to net operating loss carryforwards, tax credit carryforwards, and charitable contribution carryforwards at December 31, 2019 and 2018:

	Ameren Missouri		Ameren Illinois		Other			Ameren
2019
Tax credit carryforwards:
Federal(a)	$	25	$	3	$	67		$	95
State(b)	—		—		3			3
Total tax credit carryforwards	$	25	$	3	$	70		$	98
Charitable contribution carryforwards(c)	$	—	$	—	$	3		$	3
Valuation allowance(c)	—		—		(3		)	(3		)
Total charitable contribution carryforwards	$	—	$	—	$	—		$	—
2018
Net operating loss carryforwards:
Federal	$	—	$	23	$	55		$	78
State	—		—		13			13
Total net operating loss carryforwards	$	—	$	23	$	68		$	91
Tax credit carryforwards:
Federal	$	35	$	3	$	79		$	117
State	—		—		10			10
Total tax credit carryforwards	$	35	$	3	$	89		$	127
Charitable contribution carryforwards	$	—	$	—	$	14		$	14
Valuation allowance	—		—		(5		)	(5		)
Total charitable contribution carryforwards	$	—	$	—	$	9		$	9

(a) Will expire between 2029 and 2039.

(b) Will expire between 2022 and 2024.

(c) See Schedule II under Part IV, Item 15, in this report for information on changes in the valuation allowance.