Derivative Instruments (Fair Value Of Financial Instruments) (Details) - Commodity Contracts [Member] - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Derivatives, Fair Value [Line Items]
Current derivative assets	$ 67	$ 111
Non-current derivative assets	62	126
Current derivative liabilities	32	59
Non-current derivative liabilities	34	20
IPL [Member]
Derivatives, Fair Value [Line Items]
Current derivative assets	51	69
Non-current derivative assets	34	69
Current derivative liabilities	15	40
Non-current derivative liabilities	6	6
WPL [Member]
Derivatives, Fair Value [Line Items]
Current derivative assets	16	42
Non-current derivative assets	28	57
Current derivative liabilities	17	19
Non-current derivative liabilities	$ 28	$ 14