Derivative Instruments (Balance Sheet Offsetting) (Details) - Commodity Contracts [Member] - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Derivative Instruments [Line Items]
Derivative assets, Gross (as reported)	$ 360	$ 176
Derivative assets, Net	308	171
Derivative liabilities, Gross (as reported)	98	9
Derivative liabilities, Net	46	4
IPL [Member]
Derivative Instruments [Line Items]
Derivative assets, Gross (as reported)	202	84
Derivative assets, Net	165	83
Derivative liabilities, Gross (as reported)	66	4
Derivative liabilities, Net	29	3
WPL [Member]
Derivative Instruments [Line Items]
Derivative assets, Gross (as reported)	158	92
Derivative assets, Net	143	88
Derivative liabilities, Gross (as reported)	32	5
Derivative liabilities, Net	$ 17	$ 1

Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

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Fair value, after effects of master netting arrangements, of financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset offset against an obligation to return collateral. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

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