Benefit Plans (Defined Benefit Pension And Other Postretirement Benefits Plans) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Defined benefit pension plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1	$ 1
Interest cost	11	11
Expected return on plan assets	(13)	(13)
Amortization of actuarial loss	6	7
Total	5	6
OPEB Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	1
Interest cost	2	2
Expected return on plan assets	(1)	(1)
Amortization of actuarial loss	0	0
Total	1	2
IPL [Member] | Defined benefit pension plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1
Interest cost	5	5
Expected return on plan assets	(7)	(7)
Amortization of actuarial loss	2	3
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]
Interest cost	5	5
Expected return on plan assets	(6)	(5)
Amortization of actuarial loss	3	3
Total	2	3
WPL [Member] | OPEB Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	1	1
Expected return on plan assets	0	0
Amortization of actuarial loss	0	0
Total	$ 1	$ 1