Benefit Plans (Defined Benefit Pension And Other Postretirement Benefits Plans) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Defined benefit pension plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 2	$ 3
Interest cost	9	8
Expected return on plan assets	(17)	(17)
Amortization of actuarial loss	8	10
Total	2	4
OPEB Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1
Interest cost	1	1
Expected return on plan assets	(1)	(1)
Amortization of actuarial loss	1	1
Total	2	2
IPL [Member] | Defined benefit pension plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	2	2
Interest cost	4	4
Expected return on plan assets	(8)	(8)
Amortization of actuarial loss	3	4
Total	1	2
IPL [Member] | OPEB Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0
Interest cost	1	1
Expected return on plan assets	(1)	(1)
Amortization of actuarial loss	0	0
Total	0	0
WPL [Member] | Defined benefit pension plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1
Interest cost	4	4
Expected return on plan assets	(8)	(8)
Amortization of actuarial loss	4	5
Total	1	2
WPL [Member] | OPEB Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0
Interest cost	1	0
Expected return on plan assets	0	0
Amortization of actuarial loss	0	1
Total	$ 1	$ 1