Derivative Instruments (Balance Sheet Offsetting) (Details) - Commodity Contracts [Member] - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Derivative [Line Items]
Derivative assets, Gross (as reported)	$ 237	$ 176
Derivative assets, net	193	171
Derivative liabilities, gross (as reported)	79	9
Derivative liabilities, net	35	4
IPL [Member]
Derivative [Line Items]
Derivative assets, Gross (as reported)	138	84
Derivative assets, net	108	83
Derivative liabilities, gross (as reported)	46	4
Derivative liabilities, net	16	3
WPL [Member]
Derivative [Line Items]
Derivative assets, Gross (as reported)	99	92
Derivative assets, net	85	88
Derivative liabilities, gross (as reported)	33	5
Derivative liabilities, net	$ 19	$ 1

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