Common Equity (Changes in Shareowners' Equity) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	$ 6,777
Beginning balance	6,777	$ 6,276
Net income attributable to common shareowners	158	163
Net income	158	163
Common stock dividends	(123)	(113)
Shareowner Direct Plan issuances	6	6
Equity-based compensation plans and other	(2)	(3)
Other comprehensive income (loss), net of tax	1	(1)
Ending balance	6,817
Ending balance	$ 6,817	$ 6,328
Common stock dividends (in dollars per share)	$ 0.48	$ 0.4525
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	3,030	2,777
Shareowner Direct Plan issuances	6	6
Equity-based compensation plans and other	(3)	(3)
Ending balance	3,033	2,780
Retained Earnings [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	3,756	3,509
Net income attributable to common shareowners	158	163
Common stock dividends	(123)	(113)
Ending balance	3,791	3,559
Accumulated Other Comprehensive Income (Loss) [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	1	0
Other comprehensive income (loss), net of tax	1	(1)
Ending balance	2	(1)
Shares in Deferred Compensation Trust [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	(13)	(13)
Equity-based compensation plans and other	1
Ending balance	(12)	(13)
IPL [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	3,974
Beginning balance	3,974	3,808
Net income	63	72
Common stock dividends	(50)	(70)
Capital contributions from parent	50	0
Ending balance	4,037
Ending balance	4,037	3,810
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	2,887	2,807
Capital contributions from parent	50
Ending balance	2,937	2,807
IPL [Member] | Retained Earnings [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	1,054	968
Net income	63	72
Common stock dividends	(50)	(70)
Ending balance	1,067	970
WPL [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	3,897
Beginning balance	3,897	3,491
Net income	92	88
Common stock dividends	(49)	(46)
Capital contributions from parent	55	180
Ending balance	3,995
Ending balance	3,995	3,713
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	2,478	2,233
Capital contributions from parent	55	180
Ending balance	2,533	2,413
WPL [Member] | Retained Earnings [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	1,353	1,192
Net income	92	88
Common stock dividends	(49)	(46)
Ending balance	$ 1,396	$ 1,234