Common Equity (Tables)

3 Months Ended

Mar. 31, 2023

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, 2023	251,134,966
Shareowner Direct Plan	118,488
Equity-based compensation plans	134,334
Shares outstanding, March 31, 2023	251,387,788

Changes in Shareowners' Equity

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

Alliant Energy				Accumulated	Shares in
		Additional		Other	Deferred	Total
	Common	Paid-In	Retained	Comprehensive	Compensation	Common
	Stock	Capital	Earnings	Loss	Trust	Equity
Three Months Ended March 31, 2023
Beginning balance, December 31, 2022	$3	$2,777	$3,509	$—	($13)	$6,276
Net income attributable to Alliant Energy common shareowners			163			163
Common stock dividends ($0.4525 per share)			(113)			(113)
Shareowner Direct Plan issuances		6				6
Equity-based compensation plans and other		(3)				(3)
Other comprehensive loss, net of tax				(1)		(1)
Ending balance, March 31, 2023	$3	$2,780	$3,559	($1)	($13)	$6,328

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

IPL		Additional		Total
	Common	Paid-In	Retained	Common
	Stock	Capital	Earnings	Equity
Three Months Ended March 31, 2023
Beginning balance, December 31, 2022	$33	$2,807	$968	$3,808
Net income			72	72
Common stock dividends			(70)	(70)
Ending balance, March 31, 2023	$33	$2,807	$970	$3,810
Three Months Ended March 31, 2022
Beginning balance, December 31, 2021	$33	$2,807	$929	$3,769
Net income			87	87
Common stock dividends			(81)	(81)
Ending balance, March 31, 2022	$33	$2,807	$935	$3,775

WPL		Additional		Total
	Common	Paid-In	Retained	Common
	Stock	Capital	Earnings	Equity
Three Months Ended March 31, 2023
Beginning balance, December 31, 2022	$66	$2,233	$1,192	$3,491
Net income			88	88
Common stock dividends			(46)	(46)
Capital contributions from parent		180		180
Ending balance, March 31, 2023	$66	$2,413	$1,234	$3,713
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

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				Accumulated	Shares in
		Additional		Other	Deferred	Total
	Common	Paid-In	Retained	Comprehensive	Compensation	Common
	Stock	Capital	Earnings	Loss	Trust	Equity
Three Months Ended March 31, 2023
Beginning balance, December 31, 2022	$3	$2,777	$3,509	$—	($13)	$6,276
Net income attributable to Alliant Energy common shareowners			163			163
Common stock dividends ($0.4525 per share)			(113)			(113)
Shareowner Direct Plan issuances		6				6
Equity-based compensation plans and other		(3)				(3)
Other comprehensive loss, net of tax				(1)		(1)
Ending balance, March 31, 2023	$3	$2,780	$3,559	($1)	($13)	$6,328

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

IPL		Additional		Total
	Common	Paid-In	Retained	Common
	Stock	Capital	Earnings	Equity
Three Months Ended March 31, 2023
Beginning balance, December 31, 2022	$33	$2,807	$968	$3,808
Net income			72	72
Common stock dividends			(70)	(70)
Ending balance, March 31, 2023	$33	$2,807	$970	$3,810
Three Months Ended March 31, 2022
Beginning balance, December 31, 2021	$33	$2,807	$929	$3,769
Net income			87	87
Common stock dividends			(81)	(81)
Ending balance, March 31, 2022	$33	$2,807	$935	$3,775

WPL		Additional		Total
	Common	Paid-In	Retained	Common
	Stock	Capital	Earnings	Equity
Three Months Ended March 31, 2023
Beginning balance, December 31, 2022	$66	$2,233	$1,192	$3,491
Net income			88	88
Common stock dividends			(46)	(46)
Capital contributions from parent		180		180
Ending balance, March 31, 2023	$66	$2,413	$1,234	$3,713
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

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				Accumulated	Shares in
		Additional		Other	Deferred	Total
	Common	Paid-In	Retained	Comprehensive	Compensation	Common
	Stock	Capital	Earnings	Loss	Trust	Equity
Three Months Ended March 31, 2023
Beginning balance, December 31, 2022	$3	$2,777	$3,509	$—	($13)	$6,276
Net income attributable to Alliant Energy common shareowners			163			163
Common stock dividends ($0.4525 per share)			(113)			(113)
Shareowner Direct Plan issuances		6				6
Equity-based compensation plans and other		(3)				(3)
Other comprehensive loss, net of tax				(1)		(1)
Ending balance, March 31, 2023	$3	$2,780	$3,559	($1)	($13)	$6,328

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

IPL		Additional		Total
	Common	Paid-In	Retained	Common
	Stock	Capital	Earnings	Equity
Three Months Ended March 31, 2023
Beginning balance, December 31, 2022	$33	$2,807	$968	$3,808
Net income			72	72
Common stock dividends			(70)	(70)
Ending balance, March 31, 2023	$33	$2,807	$970	$3,810
Three Months Ended March 31, 2022
Beginning balance, December 31, 2021	$33	$2,807	$929	$3,769
Net income			87	87
Common stock dividends			(81)	(81)
Ending balance, March 31, 2022	$33	$2,807	$935	$3,775

WPL		Additional		Total
	Common	Paid-In	Retained	Common
	Stock	Capital	Earnings	Equity
Three Months Ended March 31, 2023
Beginning balance, December 31, 2022	$66	$2,233	$1,192	$3,491
Net income			88	88
Common stock dividends			(46)	(46)
Capital contributions from parent		180		180
Ending balance, March 31, 2023	$66	$2,413	$1,234	$3,713
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