Common Equity (Changes in Shareowners' Equity) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	$ 6,276
Beginning balance	6,276	$ 5,990
Net income attributable to common shareowners	163	192
Net income	163	192
Common stock dividends	(113)	(107)
Shareowner Direct Plan issuances	6	7
Equity-based compensation plans and other	(3)	(5)
Other comprehensive loss, net of tax	(1)
Ending balance	6,328
Ending balance	$ 6,328	$ 6,077
Common stock dividends (in dollars per share)	$ 0.4525	$ 0.4275
Common Stock [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	$ 3	$ 3
Ending balance	3	3
Additional Paid-in Capital [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	2,777	2,749
Shareowner Direct Plan issuances	6	7
Equity-based compensation plans and other	(3)	(6)
Ending balance	2,780	2,750
Retained Earnings [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	3,509	3,250
Net income attributable to common shareowners	163	192
Common stock dividends	(113)	(107)
Equity-based compensation plans and other		1
Ending balance	3,559	3,336
Accumulated Other Comprehensive Loss [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	0	0
Other comprehensive loss, net of tax	(1)
Ending balance	(1)	0
Shares in Deferred Compensation Trust [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	(13)	(12)
Ending balance	(13)	(12)
IPL [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	3,808
Beginning balance	3,808	3,769
Net income	72	87
Common stock dividends	(70)	(81)
Ending balance	3,810
Ending balance	3,810	3,775
IPL [Member] | Common Stock [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	33	33
Ending balance	33	33
IPL [Member] | Additional Paid-in Capital [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	2,807	2,807
Ending balance	2,807	2,807
IPL [Member] | Retained Earnings [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	968	929
Net income	72	87
Common stock dividends	(70)	(81)
Ending balance	970	935
WPL [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	3,491
Beginning balance	3,491	2,823
Net income	88	92
Common stock dividends	(46)	(44)
Capital contributions from parent	180	180
Ending balance	3,713
Ending balance	3,713	3,051
WPL [Member] | Common Stock [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	66	66
Ending balance	66	66
WPL [Member] | Additional Paid-in Capital [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	2,233	1,704
Capital contributions from parent	180	180
Ending balance	2,413	1,884
WPL [Member] | Retained Earnings [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	1,192	1,053
Net income	88	92
Common stock dividends	(46)	(44)
Ending balance	$ 1,234	$ 1,101