Income Taxes (Schedule Of Components Of Income Tax) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Current tax expense (benefit):
Federal	$ (3)	$ 7	$ 1
State	(6)	2	3
Deferred tax expense (benefit):
Federal	100	109	9
State	36	28	15
Production tax credits	(121)	(123)	(101)
Investment tax credits	(1)	(1)	(1)
Provision recorded as a change in accrued interest	(1)	0	0
Income tax expense (benefit)	4	22	(74)
IPL [Member]
Current tax expense (benefit):
Federal	(44)	(29)	(21)
State	(21)	(8)	(1)
Deferred tax expense (benefit):
Federal	87	91	73
State	17	1	0
Production tax credits	(95)	(105)	(87)
Investment tax credits	(1)	0	0
Provision recorded as a change in accrued interest	(1)	0	0
Income tax expense (benefit)	(58)	(50)	(36)
WPL [Member]
Current tax expense (benefit):
Federal	48	46	22
State	25	16	6
Deferred tax expense (benefit):
Federal	10	10	(75)
State	3	12	11
Production tax credits	(26)	(18)	(14)
Investment tax credits	0	0	(1)
Provision recorded as a change in accrued interest	0	0	0
Income tax expense (benefit)	$ 60	$ 66	$ (51)