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Income Taxes

12 Months Ended

Dec. 31, 2021

Income Tax [Line Items]

Income Taxes

INCOME TAXES

Income Tax Expense (Benefit) - The components of “Income tax expense (benefit)” in the income statements were as follows (in millions):

			Alliant Energy																		IPL																		WPL
			2021						2020						2019						2021						2020						2019						2021						2020						2019
Current tax expense (benefit):
Federal			$1						$1						($7)						($21)						$6						($11)						$22						($11)						$12
State			3						8						24						(1)						(1)						24						6						7						13
IPL’s tax benefit riders			—						—						(4)						—						—						(4)						—						—						—
Deferred tax expense (benefit):
Federal			9						22						70						73						30						26						(75)						(9)						31
State			15						8						42						—						(2)						31						11						10						6
Production tax credits			(101)						(95)						(55)						(87)						(80)						(42)						(14)						(15)						(13)
Investment tax credits			(1)						(1)						(1)						—						—						—						(1)						(1)						—
			($74)						($57)						$69						($36)						($47)						$24						($51)						($19)						$49

Income Tax Rates - The overall income tax rates shown in the following table were computed by dividing income tax expense (benefit) by income from continuing operations before income taxes.

			Alliant Energy																		IPL																		WPL
			2021						2020						2019						2021						2020						2019						2021						2020						2019
Statutory federal income tax rate			21		%				21		%				21		%				21		%				21		%				21		%				21		%				21		%				21		%
State income taxes, net of federal benefits			2						2						7						(1)						(1)						8						6						6						6
Amortization of excess deferred taxes (Refer to Note 2)			(18)						(13)						(1)						(4)						(5)						—						(43)						(26)						(2)
Production tax credits			(17)						(17)						(9)						(27)						(28)						(13)						(6)						(7)						(5)
Effect of rate-making on property-related differences			(1)						(3)						(6)						(2)						(4)						(10)						(1)						(2)						(3)
Adjustment for prior period taxes			1						1						1						2						1						3						—						—						—
IPL’s tax benefit riders			—						—						(1)						—						—						(1)						—						—						—
Other items, net			—						(1)						(1)						—						—						—						(1)						—						—
Overall income tax rate			(12		%)				(10		%)				11		%				(11		%)				(16		%)				8		%				(24		%)				(8		%)				17		%

Deferred Tax Assets and Liabilities - The deferred tax assets and liabilities included on the balance sheets at December 31 arise from the following temporary differences (in millions):

			Alliant Energy												IPL												WPL
			2021						2020						2021						2020						2021						2020
Deferred tax liabilities:
Property			$2,389						$2,232						$1,416						$1,312						$913						$854
ATC Holdings			123						116						—						—						—						—
Other			111						101						76						83						50						41
Total deferred tax liabilities			2,623						2,449						1,492						1,395						963						895
Deferred tax assets:
Federal credit carryforwards			560						454						345						258						192						175
Net operating losses carryforwards - federal			39						77						36						71						—						1
Net operating losses carryforwards - state			38						37						3						1						—						—
Other			65						73						25						30						18						18
Subtotal deferred tax assets			702						641						409						360						210						194
Valuation allowances			(6)						(6)						—						—						—						(1)
Total deferred tax assets			696						635						409						360						210						193
Total deferred tax liabilities, net			$1,927						$1,814						$1,083						$1,035						$753						$702

Carryforwards - At December 31, 2021, carryforwards and expiration dates were estimated as follows (in millions):

			Range of Expiration Dates						Alliant Energy						IPL						WPL
Federal net operating losses			2037						$186						$172						$1
State net operating losses			2022-2041						619						28						2
Federal tax credits			2022-2041						560						345						192

Valuation Allowances - Alliant Energy currently expects its federal net operating losses carryforwards will not be fully utilized until 2023. Because taxable income must be reduced by federal net operating losses carryforwards prior to utilizing federal tax credit carryforwards, Alliant Energy currently does not expect to utilize 2002 vintage federal credit carryforwards prior to their expiration in 2022, resulting in valuation allowances as of December 31, 2021.

Uncertain Tax Positions - At December 31, 2021, 2020 and 2019, there were no uncertain tax positions or penalties accrued related to uncertain tax positions. As of December 31, 2021, no material changes to unrecognized tax benefits are expected during the next 12 months.

Open tax years - Tax years that remain subject to the statute of limitations in the major jurisdictions for each of Alliant Energy, IPL and WPL are as follows:

Consolidated federal income tax returns (a)			2018			-			2020
Consolidated Iowa income tax returns (b)			2018			-			2020
Wisconsin combined tax returns (c)			2017			-			2020

(a)The 2018 and 2019 federal tax returns are effectively settled as a result of participation in the IRS Compliance Assurance Program, which allows Alliant Energy and the IRS to work together to resolve issues related to Alliant Energy’s current tax year before filing its federal income tax return. The statute of limitations for these federal tax returns expires three years from each filing date.

(b)The statute of limitations for these Iowa tax returns expires three years from each filing date.

(c)The statute of limitations for these Wisconsin combined tax returns expires four years from each filing date.

Iowa Tax Reform - In 2018, Iowa tax reform was enacted, resulting in a reduction in the Iowa income tax rate from 12% to 9.8%, effective January 1, 2021, and the elimination of the deduction for federal income taxes, effective January 1, 2022, for taxes related to 2020 and prior.

IPL [Member]

Income Tax [Line Items]

Income Taxes

INCOME TAXES

Income Tax Expense (Benefit) - The components of “Income tax expense (benefit)” in the income statements were as follows (in millions):

			Alliant Energy																		IPL																		WPL
			2021						2020						2019						2021						2020						2019						2021						2020						2019
Current tax expense (benefit):
Federal			$1						$1						($7)						($21)						$6						($11)						$22						($11)						$12
State			3						8						24						(1)						(1)						24						6						7						13
IPL’s tax benefit riders			—						—						(4)						—						—						(4)						—						—						—
Deferred tax expense (benefit):
Federal			9						22						70						73						30						26						(75)						(9)						31
State			15						8						42						—						(2)						31						11						10						6
Production tax credits			(101)						(95)						(55)						(87)						(80)						(42)						(14)						(15)						(13)
Investment tax credits			(1)						(1)						(1)						—						—						—						(1)						(1)						—
			($74)						($57)						$69						($36)						($47)						$24						($51)						($19)						$49

Income Tax Rates - The overall income tax rates shown in the following table were computed by dividing income tax expense (benefit) by income from continuing operations before income taxes.

			Alliant Energy																		IPL																		WPL
			2021						2020						2019						2021						2020						2019						2021						2020						2019
Statutory federal income tax rate			21		%				21		%				21		%				21		%				21		%				21		%				21		%				21		%				21		%
State income taxes, net of federal benefits			2						2						7						(1)						(1)						8						6						6						6
Amortization of excess deferred taxes (Refer to Note 2)			(18)						(13)						(1)						(4)						(5)						—						(43)						(26)						(2)
Production tax credits			(17)						(17)						(9)						(27)						(28)						(13)						(6)						(7)						(5)
Effect of rate-making on property-related differences			(1)						(3)						(6)						(2)						(4)						(10)						(1)						(2)						(3)
Adjustment for prior period taxes			1						1						1						2						1						3						—						—						—
IPL’s tax benefit riders			—						—						(1)						—						—						(1)						—						—						—
Other items, net			—						(1)						(1)						—						—						—						(1)						—						—
Overall income tax rate			(12		%)				(10		%)				11		%				(11		%)				(16		%)				8		%				(24		%)				(8		%)				17		%

Deferred Tax Assets and Liabilities - The deferred tax assets and liabilities included on the balance sheets at December 31 arise from the following temporary differences (in millions):

			Alliant Energy												IPL												WPL
			2021						2020						2021						2020						2021						2020
Deferred tax liabilities:
Property			$2,389						$2,232						$1,416						$1,312						$913						$854
ATC Holdings			123						116						—						—						—						—
Other			111						101						76						83						50						41
Total deferred tax liabilities			2,623						2,449						1,492						1,395						963						895
Deferred tax assets:
Federal credit carryforwards			560						454						345						258						192						175
Net operating losses carryforwards - federal			39						77						36						71						—						1
Net operating losses carryforwards - state			38						37						3						1						—						—
Other			65						73						25						30						18						18
Subtotal deferred tax assets			702						641						409						360						210						194
Valuation allowances			(6)						(6)						—						—						—						(1)
Total deferred tax assets			696						635						409						360						210						193
Total deferred tax liabilities, net			$1,927						$1,814						$1,083						$1,035						$753						$702

Carryforwards - At December 31, 2021, carryforwards and expiration dates were estimated as follows (in millions):

			Range of Expiration Dates						Alliant Energy						IPL						WPL
Federal net operating losses			2037						$186						$172						$1
State net operating losses			2022-2041						619						28						2
Federal tax credits			2022-2041						560						345						192

Valuation Allowances - Alliant Energy currently expects its federal net operating losses carryforwards will not be fully utilized until 2023. Because taxable income must be reduced by federal net operating losses carryforwards prior to utilizing federal tax credit carryforwards, Alliant Energy currently does not expect to utilize 2002 vintage federal credit carryforwards prior to their expiration in 2022, resulting in valuation allowances as of December 31, 2021.

Uncertain Tax Positions - At December 31, 2021, 2020 and 2019, there were no uncertain tax positions or penalties accrued related to uncertain tax positions. As of December 31, 2021, no material changes to unrecognized tax benefits are expected during the next 12 months.

Open tax years - Tax years that remain subject to the statute of limitations in the major jurisdictions for each of Alliant Energy, IPL and WPL are as follows:

Consolidated federal income tax returns (a)			2018			-			2020
Consolidated Iowa income tax returns (b)			2018			-			2020
Wisconsin combined tax returns (c)			2017			-			2020

(a)The 2018 and 2019 federal tax returns are effectively settled as a result of participation in the IRS Compliance Assurance Program, which allows Alliant Energy and the IRS to work together to resolve issues related to Alliant Energy’s current tax year before filing its federal income tax return. The statute of limitations for these federal tax returns expires three years from each filing date.

(b)The statute of limitations for these Iowa tax returns expires three years from each filing date.

(c)The statute of limitations for these Wisconsin combined tax returns expires four years from each filing date.

Iowa Tax Reform - In 2018, Iowa tax reform was enacted, resulting in a reduction in the Iowa income tax rate from 12% to 9.8%, effective January 1, 2021, and the elimination of the deduction for federal income taxes, effective January 1, 2022, for taxes related to 2020 and prior.

WPL [Member]

Income Tax [Line Items]

Income Taxes

INCOME TAXES

Income Tax Expense (Benefit) - The components of “Income tax expense (benefit)” in the income statements were as follows (in millions):

			Alliant Energy																		IPL																		WPL
			2021						2020						2019						2021						2020						2019						2021						2020						2019
Current tax expense (benefit):
Federal			$1						$1						($7)						($21)						$6						($11)						$22						($11)						$12
State			3						8						24						(1)						(1)						24						6						7						13
IPL’s tax benefit riders			—						—						(4)						—						—						(4)						—						—						—
Deferred tax expense (benefit):
Federal			9						22						70						73						30						26						(75)						(9)						31
State			15						8						42						—						(2)						31						11						10						6
Production tax credits			(101)						(95)						(55)						(87)						(80)						(42)						(14)						(15)						(13)
Investment tax credits			(1)						(1)						(1)						—						—						—						(1)						(1)						—
			($74)						($57)						$69						($36)						($47)						$24						($51)						($19)						$49

Income Tax Rates - The overall income tax rates shown in the following table were computed by dividing income tax expense (benefit) by income from continuing operations before income taxes.

			Alliant Energy																		IPL																		WPL
			2021						2020						2019						2021						2020						2019						2021						2020						2019
Statutory federal income tax rate			21		%				21		%				21		%				21		%				21		%				21		%				21		%				21		%				21		%
State income taxes, net of federal benefits			2						2						7						(1)						(1)						8						6						6						6
Amortization of excess deferred taxes (Refer to Note 2)			(18)						(13)						(1)						(4)						(5)						—						(43)						(26)						(2)
Production tax credits			(17)						(17)						(9)						(27)						(28)						(13)						(6)						(7)						(5)
Effect of rate-making on property-related differences			(1)						(3)						(6)						(2)						(4)						(10)						(1)						(2)						(3)
Adjustment for prior period taxes			1						1						1						2						1						3						—						—						—
IPL’s tax benefit riders			—						—						(1)						—						—						(1)						—						—						—
Other items, net			—						(1)						(1)						—						—						—						(1)						—						—
Overall income tax rate			(12		%)				(10		%)				11		%				(11		%)				(16		%)				8		%				(24		%)				(8		%)				17		%

Deferred Tax Assets and Liabilities - The deferred tax assets and liabilities included on the balance sheets at December 31 arise from the following temporary differences (in millions):

			Alliant Energy												IPL												WPL
			2021						2020						2021						2020						2021						2020
Deferred tax liabilities:
Property			$2,389						$2,232						$1,416						$1,312						$913						$854
ATC Holdings			123						116						—						—						—						—
Other			111						101						76						83						50						41
Total deferred tax liabilities			2,623						2,449						1,492						1,395						963						895
Deferred tax assets:
Federal credit carryforwards			560						454						345						258						192						175
Net operating losses carryforwards - federal			39						77						36						71						—						1
Net operating losses carryforwards - state			38						37						3						1						—						—
Other			65						73						25						30						18						18
Subtotal deferred tax assets			702						641						409						360						210						194
Valuation allowances			(6)						(6)						—						—						—						(1)
Total deferred tax assets			696						635						409						360						210						193
Total deferred tax liabilities, net			$1,927						$1,814						$1,083						$1,035						$753						$702

Carryforwards - At December 31, 2021, carryforwards and expiration dates were estimated as follows (in millions):

			Range of Expiration Dates						Alliant Energy						IPL						WPL
Federal net operating losses			2037						$186						$172						$1
State net operating losses			2022-2041						619						28						2
Federal tax credits			2022-2041						560						345						192

Valuation Allowances - Alliant Energy currently expects its federal net operating losses carryforwards will not be fully utilized until 2023. Because taxable income must be reduced by federal net operating losses carryforwards prior to utilizing federal tax credit carryforwards, Alliant Energy currently does not expect to utilize 2002 vintage federal credit carryforwards prior to their expiration in 2022, resulting in valuation allowances as of December 31, 2021.

Uncertain Tax Positions - At December 31, 2021, 2020 and 2019, there were no uncertain tax positions or penalties accrued related to uncertain tax positions. As of December 31, 2021, no material changes to unrecognized tax benefits are expected during the next 12 months.

Open tax years - Tax years that remain subject to the statute of limitations in the major jurisdictions for each of Alliant Energy, IPL and WPL are as follows:

Consolidated federal income tax returns (a)			2018			-			2020
Consolidated Iowa income tax returns (b)			2018			-			2020
Wisconsin combined tax returns (c)			2017			-			2020

(a)The 2018 and 2019 federal tax returns are effectively settled as a result of participation in the IRS Compliance Assurance Program, which allows Alliant Energy and the IRS to work together to resolve issues related to Alliant Energy’s current tax year before filing its federal income tax return. The statute of limitations for these federal tax returns expires three years from each filing date.

(b)The statute of limitations for these Iowa tax returns expires three years from each filing date.

(c)The statute of limitations for these Wisconsin combined tax returns expires four years from each filing date.

Iowa Tax Reform - In 2018, Iowa tax reform was enacted, resulting in a reduction in the Iowa income tax rate from 12% to 9.8%, effective January 1, 2021, and the elimination of the deduction for federal income taxes, effective January 1, 2022, for taxes related to 2020 and prior.

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Income tax

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No definition available.

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The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

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-Publisher FASB
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