Common Equity (Changes in Shareowners' Equity) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance			$ 5,990
Beginning balance	$ 6,166	$ 6,019	5,990	$ 5,888
Net income attributable to common shareowners	227	256	579	571
Net income	227	259	579	579
Common stock dividends	(106)	(101)	(322)	(304)
Shareowner Direct Plan issuances	6	6	19	22
Equity-based compensation plans and other	1	5	(1)	8
Contributions from noncontrolling interest			29
Distributions to noncontrolling interest	(29)		(29)
Ending balance	6,265		6,265
Ending balance	$ 6,265	$ 6,185	$ 6,265	$ 6,185
Common stock dividends (in dollars per share)	$ 0.4275	$ 0.4025	$ 1.2825	$ 1.2075
Common Stock [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	$ 3	$ 3	$ 3	$ 2
Shareowner Direct Plan issuances				1
Ending balance	3	3	3	3
Additional Paid-in Capital [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	2,759	2,722	2,749	2,704
Shareowner Direct Plan issuances	6	6	19	21
Equity-based compensation plans and other	2	5	(1)	8
Ending balance	2,767	2,733	2,767	2,733
Retained Earnings [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	3,387	3,106	3,250	2,994
Net income attributable to common shareowners	227	256	579	571
Common stock dividends	(106)	(101)	(322)	(304)
Equity-based compensation plans and other			1
Ending balance	3,508	3,261	3,508	3,261
Accumulated Other Comprehensive Loss [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	0	(1)	0	(1)
Ending balance	0	(1)	0	(1)
Shares in Deferred Compensation Trust [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	(12)	(11)	(12)	(11)
Equity-based compensation plans and other	(1)		(1)
Ending balance	(13)	(11)	(13)	(11)
Noncontrolling Interest [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	29		0
Contributions from noncontrolling interest			29
Distributions to noncontrolling interest	(29)		(29)
Ending balance	0		0
Cumulative Preferred Stock [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance		200		200
Ending balance		200		200
IPL [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance			3,769
Beginning balance	3,782	3,979	3,769	3,964
Net income attributable to common shareowners	154	157	327	322
Net income	154	160	327	330
Common stock dividends	(80)	(101)	(240)	(301)
Capital contributions from parent			0	50
Ending balance	3,856		3,856
Ending balance	3,856	4,035	3,856	4,035
IPL [Member] | Common Stock [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	33	33	33	33
Ending balance	33	33	33	33
IPL [Member] | Additional Paid-in Capital [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	2,807	2,802	2,807	2,752
Capital contributions from parent				50
Ending balance	2,807	2,802	2,807	2,802
IPL [Member] | Retained Earnings [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	942	944	929	979
Net income attributable to common shareowners	154	157	327	322
Common stock dividends	(80)	(101)	(240)	(301)
Ending balance	1,016	1,000	1,016	1,000
IPL [Member] | Cumulative Preferred Stock [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	0	200	0	200
Ending balance	0	200	0	200
WPL [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance			2,823
Beginning balance	3,183	2,725	2,823	2,478
Net income	91	93	247	215
Common stock dividends	(44)	(41)	(133)	(126)
Equity-based compensation plans and other			(1)
Capital contributions from parent	155	35	420	245
Contributions from noncontrolling interest			29
Distributions to noncontrolling interest	(29)		(29)
Ending balance	3,356		3,356
Ending balance	3,356	2,812	3,356	2,812
WPL [Member] | Common Stock [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	66	66	66	66
Ending balance	66	66	66	66
WPL [Member] | Additional Paid-in Capital [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	1,968	1,669	1,704	1,459
Equity-based compensation plans and other			(1)
Capital contributions from parent	155	35	420	245
Ending balance	2,123	1,704	2,123	1,704
WPL [Member] | Retained Earnings [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	1,120	990	1,053	953
Net income	91	93	247	215
Common stock dividends	(44)	(41)	(133)	(126)
Ending balance	1,167	1,042	1,167	1,042
WPL [Member] | Noncontrolling Interest [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	29	0	0	0
Contributions from noncontrolling interest			29
Distributions to noncontrolling interest	(29)		(29)
Ending balance	$ 0	$ 0	$ 0	$ 0