Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2024	Dec. 31, 2023
Income Taxes [Line Items]
State income tax rate, percent			9.80%
Regulatory assets			$ (102)	$ (21)
Income tax expense (benefit)	$ 14	$ (21)	26	(66)
Tax-related [Member]
Income Taxes [Line Items]
Regulatory assets	76
Income tax expense (benefit)	8
Forecast [Member]
Income Taxes [Line Items]
State income tax rate, percent					5.50%	8.40%
IPL [Member]
Income Taxes [Line Items]
Regulatory assets			18	(33)
Income tax expense (benefit)	(16)	(12)	(39)	(34)
IPL [Member] | Tax-related [Member]
Income Taxes [Line Items]
Regulatory assets	76
WPL [Member]
Income Taxes [Line Items]
Regulatory assets			(120)	11
Income tax expense (benefit)	$ 16	$ (15)	$ 50	$ (41)