Benefit Plans (Net Periodic Benefit Costs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Pension settlement losses	$ 3	$ (3)	$ (6)
Defined Benefit Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	5	5	9
Interest cost	45	47	36
Expected return on plan assets	(55)	(53)	(69)
Amortization of prior service cost (credit)	(1)	(1)	(1)
Amortization of actuarial loss	24	28	32
Settlement losses	0	0	26
Total	18	26	33
Pension settlement losses			7
Other Postretirement Benefits Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	2	2	3
Interest cost	8	9	6
Expected return on plan assets	(5)	(5)	(5)
Amortization of prior service cost (credit)	0	0	0
Amortization of actuarial loss	0	1	2
Settlement losses	0	0	0
Total	5	7	6
IPL [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension settlement losses	12	(2)	(6)
IPL [Member] | Defined Benefit Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	3	3	6
Interest cost	20	21	16
Expected return on plan assets	(26)	(26)	(31)
Amortization of actuarial loss	9	11	13
Settlement losses	0	0	13
Total	6	9	17
Pension settlement losses			7
IPL [Member] | Other Postretirement Benefits Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1	1
Interest cost	3	3	2
Expected return on plan assets	(4)	(3)	(4)
Amortization of actuarial loss	0	1	1
Settlement losses	0	0	0
Total	0	2	0
WPL [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension settlement losses	(8)	3	1
WPL [Member] | Defined Benefit Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	2	2	3
Interest cost	20	20	16
Expected return on plan assets	(23)	(22)	(31)
Amortization of actuarial loss	11	13	15
Settlement losses	0	0	13
Total	10	13	16
WPL [Member] | Other Postretirement Benefits Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1	1
Interest cost	3	3	2
Expected return on plan assets	(1)	(1)	(1)
Amortization of actuarial loss	0	1	2
Settlement losses	0	0	0
Total	$ 3	$ 4	$ 4