Receivables (Details of Accounts Receivable) (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Accounts Receivable [Line Items]
Customer	$ 114	$ 93
Unbilled utility revenues	115	91
Deferred proceeds	185	214
Other	109	53
Allowance for expected credit losses	(7)	(11)
Accounts receivable, less allowance for expected credit losses	516	440
IPL [Member]
Accounts Receivable [Line Items]
Customer	0	0
Unbilled utility revenues	0	0
Deferred proceeds	185	214
Other	74	28
Allowance for expected credit losses	0	(1)
Accounts receivable, less allowance for expected credit losses	259	241
WPL [Member]
Accounts Receivable [Line Items]
Customer	102	82
Unbilled utility revenues	115	91
Other	34	25
Allowance for expected credit losses	(7)	(10)
Accounts receivable, less allowance for expected credit losses	$ 244	$ 188