Regulatory Matters (Assets Retired Early) (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Regulatory Assets [Line Items]
Regulatory assets	$ 2,261	$ 2,046
Assets retired early [Member]
Regulatory Assets [Line Items]
Regulatory assets	273	70
IPL [Member]
Regulatory Assets [Line Items]
Regulatory assets	1,577	1,386
IPL [Member] | Assets retired early [Member]
Regulatory Assets [Line Items]
Regulatory assets	259	53
IPL [Member] | Assets retired early [Member] | Lansing [Member]
Regulatory Assets [Line Items]
Regulatory assets	216
IPL [Member] | Assets retired early [Member] | Analog Electric Meters [Member]
Regulatory Assets [Line Items]
Regulatory assets	20
IPL [Member] | Assets retired early [Member] | Sutherland Units 1 and 3 [Member]
Regulatory Assets [Line Items]
Regulatory assets	12
IPL [Member] | Assets retired early [Member] | M.L. Kapp Unit 2 [Member]
Regulatory Assets [Line Items]
Regulatory assets	11
WPL [Member]
Regulatory Assets [Line Items]
Regulatory assets	684	660
WPL [Member] | Assets retired early [Member]
Regulatory Assets [Line Items]
Regulatory assets	14	$ 17
WPL [Member] | Assets retired early [Member] | Edgewater Unit 4 [Member]
Regulatory Assets [Line Items]
Regulatory assets	$ 14