Common Equity (Tables)

3 Months Ended

Mar. 31, 2022

Schedule of Capitalization, Equity [Line Items]

Common Share Activity

A summary of Alliant Energy’s common stock activity was as follows:

Shares outstanding, January 1, 2022	250,474,529
Shareowner Direct Plan	116,431
Equity-based compensation plans	222,768
Shares outstanding, March 31, 2022	250,813,728

Changes in Shareowners' Equity

A summary of changes in shareowners’ equity was as follows (in millions):

Alliant Energy	Total Alliant Energy Common Equity
				Accumulated	Shares in	Cumulative
		Additional		Other	Deferred	Preferred
	Common	Paid-In	Retained	Comprehensive	Compensation	Stock	Total
	Stock	Capital	Earnings	Loss	Trust	of IPL	Equity
Three Months Ended March 31, 2022
Beginning balance, December 31, 2021	$3	$2,749	$3,250	$—	($12)	$—	$5,990
Net income attributable to Alliant Energy common shareowners			192				192
Common stock dividends ($0.4275 per share)			(107)				(107)
Shareowner Direct Plan issuances		7					7
Equity-based compensation plans and other		(6)	1				(5)
Ending balance, March 31, 2022	$3	$2,750	$3,336	$—	($12)	$—	$6,077
Three Months Ended March 31, 2021
Beginning balance, December 31, 2020	$2	$2,704	$2,994	($1)	($11)	$200	$5,888
Net income attributable to Alliant Energy common shareowners			171				171
Common stock dividends ($0.4025 per share)			(102)				(102)
Shareowner Direct Plan issuances	1	7					8
Equity-based compensation plans and other		1					1
Ending balance, March 31, 2021	$3	$2,712	$3,063	($1)	($11)	$200	$5,966

IPL	Total IPL Common Equity
		Additional		Cumulative
	Common	Paid-In	Retained	Preferred	Total
	Stock	Capital	Earnings	Stock	Equity
Three Months Ended March 31, 2022
Beginning balance, December 31, 2021	$33	$2,807	$929	$—	$3,769
Net income available for common stock			87		87
Common stock dividends			(81)		(81)
Ending balance, March 31, 2022	$33	$2,807	$935	$—	$3,775
Three Months Ended March 31, 2021
Beginning balance, December 31, 2020	$33	$2,752	$979	$200	$3,964
Net income available for common stock			79		79
Common stock dividends			(101)		(101)
Ending balance, March 31, 2021	$33	$2,752	$957	$200	$3,942

WPL		Additional		Total
	Common	Paid-In	Retained	Common
	Stock	Capital	Earnings	Equity
Three Months Ended March 31, 2022
Beginning balance, December 31, 2021	$66	$1,704	$1,053	$2,823
Net income			92	92
Common stock dividends			(44)	(44)
Capital contributions from parent		180		180
Ending balance, March 31, 2022	$66	$1,884	$1,101	$3,051
Three Months Ended March 31, 2021
Beginning balance, December 31, 2020	$66	$1,459	$953	$2,478
Net income			84	84
Common stock dividends			(42)	(42)
Capital contributions from parent		125		125
Ending balance, March 31, 2021	$66	$1,584	$995	$2,645

IPL [Member]

Schedule of Capitalization, Equity [Line Items]

Changes in Shareowners' Equity

A summary of changes in shareowners’ equity was as follows (in millions):

Alliant Energy	Total Alliant Energy Common Equity
				Accumulated	Shares in	Cumulative
		Additional		Other	Deferred	Preferred
	Common	Paid-In	Retained	Comprehensive	Compensation	Stock	Total
	Stock	Capital	Earnings	Loss	Trust	of IPL	Equity
Three Months Ended March 31, 2022
Beginning balance, December 31, 2021	$3	$2,749	$3,250	$—	($12)	$—	$5,990
Net income attributable to Alliant Energy common shareowners			192				192
Common stock dividends ($0.4275 per share)			(107)				(107)
Shareowner Direct Plan issuances		7					7
Equity-based compensation plans and other		(6)	1				(5)
Ending balance, March 31, 2022	$3	$2,750	$3,336	$—	($12)	$—	$6,077
Three Months Ended March 31, 2021
Beginning balance, December 31, 2020	$2	$2,704	$2,994	($1)	($11)	$200	$5,888
Net income attributable to Alliant Energy common shareowners			171				171
Common stock dividends ($0.4025 per share)			(102)				(102)
Shareowner Direct Plan issuances	1	7					8
Equity-based compensation plans and other		1					1
Ending balance, March 31, 2021	$3	$2,712	$3,063	($1)	($11)	$200	$5,966

IPL	Total IPL Common Equity
		Additional		Cumulative
	Common	Paid-In	Retained	Preferred	Total
	Stock	Capital	Earnings	Stock	Equity
Three Months Ended March 31, 2022
Beginning balance, December 31, 2021	$33	$2,807	$929	$—	$3,769
Net income available for common stock			87		87
Common stock dividends			(81)		(81)
Ending balance, March 31, 2022	$33	$2,807	$935	$—	$3,775
Three Months Ended March 31, 2021
Beginning balance, December 31, 2020	$33	$2,752	$979	$200	$3,964
Net income available for common stock			79		79
Common stock dividends			(101)		(101)
Ending balance, March 31, 2021	$33	$2,752	$957	$200	$3,942

WPL		Additional		Total
	Common	Paid-In	Retained	Common
	Stock	Capital	Earnings	Equity
Three Months Ended March 31, 2022
Beginning balance, December 31, 2021	$66	$1,704	$1,053	$2,823
Net income			92	92
Common stock dividends			(44)	(44)
Capital contributions from parent		180		180
Ending balance, March 31, 2022	$66	$1,884	$1,101	$3,051
Three Months Ended March 31, 2021
Beginning balance, December 31, 2020	$66	$1,459	$953	$2,478
Net income			84	84
Common stock dividends			(42)	(42)
Capital contributions from parent		125		125
Ending balance, March 31, 2021	$66	$1,584	$995	$2,645

WPL [Member]

Schedule of Capitalization, Equity [Line Items]

Changes in Shareowners' Equity

A summary of changes in shareowners’ equity was as follows (in millions):

Alliant Energy	Total Alliant Energy Common Equity
				Accumulated	Shares in	Cumulative
		Additional		Other	Deferred	Preferred
	Common	Paid-In	Retained	Comprehensive	Compensation	Stock	Total
	Stock	Capital	Earnings	Loss	Trust	of IPL	Equity
Three Months Ended March 31, 2022
Beginning balance, December 31, 2021	$3	$2,749	$3,250	$—	($12)	$—	$5,990
Net income attributable to Alliant Energy common shareowners			192				192
Common stock dividends ($0.4275 per share)			(107)				(107)
Shareowner Direct Plan issuances		7					7
Equity-based compensation plans and other		(6)	1				(5)
Ending balance, March 31, 2022	$3	$2,750	$3,336	$—	($12)	$—	$6,077
Three Months Ended March 31, 2021
Beginning balance, December 31, 2020	$2	$2,704	$2,994	($1)	($11)	$200	$5,888
Net income attributable to Alliant Energy common shareowners			171				171
Common stock dividends ($0.4025 per share)			(102)				(102)
Shareowner Direct Plan issuances	1	7					8
Equity-based compensation plans and other		1					1
Ending balance, March 31, 2021	$3	$2,712	$3,063	($1)	($11)	$200	$5,966

IPL	Total IPL Common Equity
		Additional		Cumulative
	Common	Paid-In	Retained	Preferred	Total
	Stock	Capital	Earnings	Stock	Equity
Three Months Ended March 31, 2022
Beginning balance, December 31, 2021	$33	$2,807	$929	$—	$3,769
Net income available for common stock			87		87
Common stock dividends			(81)		(81)
Ending balance, March 31, 2022	$33	$2,807	$935	$—	$3,775
Three Months Ended March 31, 2021
Beginning balance, December 31, 2020	$33	$2,752	$979	$200	$3,964
Net income available for common stock			79		79
Common stock dividends			(101)		(101)
Ending balance, March 31, 2021	$33	$2,752	$957	$200	$3,942

WPL		Additional		Total
	Common	Paid-In	Retained	Common
	Stock	Capital	Earnings	Equity
Three Months Ended March 31, 2022
Beginning balance, December 31, 2021	$66	$1,704	$1,053	$2,823
Net income			92	92
Common stock dividends			(44)	(44)
Capital contributions from parent		180		180
Ending balance, March 31, 2022	$66	$1,884	$1,101	$3,051
Three Months Ended March 31, 2021
Beginning balance, December 31, 2020	$66	$1,459	$953	$2,478
Net income			84	84
Common stock dividends			(42)	(42)
Capital contributions from parent		125		125
Ending balance, March 31, 2021	$66	$1,584	$995	$2,645