Regulatory Matters (Assets Retired Early) (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Regulatory Assets [Line Items]
Regulatory assets	$ 2,046	$ 1,940
Assets retired early [Member]
Regulatory Assets [Line Items]
Regulatory assets	70	92
IPL [Member]
Regulatory Assets [Line Items]
Regulatory assets	1,386	1,443
IPL [Member] | Assets retired early [Member]
Regulatory Assets [Line Items]
Regulatory assets	53	66
IPL [Member] | Assets retired early [Member] | Sutherland Units 1 and 3 [Member]
Regulatory Assets [Line Items]
Regulatory assets	16
IPL [Member] | Assets retired early [Member] | M.L. Kapp Unit 2 [Member]
Regulatory Assets [Line Items]
Regulatory assets	13
IPL [Member] | Assets retired early [Member] | Analog Electric Meters [Member]
Regulatory Assets [Line Items]
Regulatory assets	24
WPL [Member]
Regulatory Assets [Line Items]
Regulatory assets	660	497
WPL [Member] | Assets retired early [Member]
Regulatory Assets [Line Items]
Regulatory assets	17	$ 26
WPL [Member] | Assets retired early [Member] | Edgewater Unit 4 [Member]
Regulatory Assets [Line Items]
Regulatory assets	$ 17