Benefit Plans (Amounts Recognized On The Consolidated Balance Sheets) (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Amounts recognized on the balance sheets consist of:
Pension and other benefit obligations	$ (249)	$ (277)
Pension Plans, Defined Benefit [Member]
Amounts recognized on the balance sheets consist of:
Non-current assets	0	0
Current liabilities	(2)	(2)
Pension and other benefit obligations	(142)	(167)
Net amounts recognized at December 31	(144)	(169)
Amounts recognized in Regulatory Assets consist of:
Net actuarial loss	337	376
Prior service credit	(2)	(3)
Net amount recognized at December 31	335	373
Other Postretirement Benefits Plans [Member]
Amounts recognized on the balance sheets consist of:
Non-current assets	14	9
Current liabilities	(8)	(8)
Pension and other benefit obligations	(83)	(86)
Net amounts recognized at December 31	(77)	(85)
Amounts recognized in Regulatory Assets consist of:
Net actuarial loss	11	20
Prior service credit	0	0
Net amount recognized at December 31	11	20
IPL [Member]
Amounts recognized on the balance sheets consist of:
Pension and other benefit obligations	(51)	(62)
IPL [Member] | Pension Plans, Defined Benefit [Member]
Amounts recognized on the balance sheets consist of:
Non-current assets	0	0
Current liabilities	0	0
Pension and other benefit obligations	(35)	(45)
Net amounts recognized at December 31	(35)	(45)
Amounts recognized in Regulatory Assets consist of:
Net actuarial loss	135	154
Prior service credit	(1)	(1)
Net amount recognized at December 31	134	153
IPL [Member] | Other Postretirement Benefits Plans [Member]
Amounts recognized on the balance sheets consist of:
Non-current assets	10	6
Current liabilities	(1)	(2)
Pension and other benefit obligations	(13)	(14)
Net amounts recognized at December 31	(4)	(10)
Amounts recognized in Regulatory Assets consist of:
Net actuarial loss	9	14
Prior service credit	0	0
Net amount recognized at December 31	9	14
WPL [Member]
Amounts recognized on the balance sheets consist of:
Pension and other benefit obligations	(121)	(140)
WPL [Member] | Pension Plans, Defined Benefit [Member]
Amounts recognized on the balance sheets consist of:
Non-current assets	0	0
Current liabilities	0	0
Pension and other benefit obligations	(75)	(90)
Net amounts recognized at December 31	(75)	(90)
Amounts recognized in Regulatory Assets consist of:
Net actuarial loss	148	165
Prior service credit	0	0
Net amount recognized at December 31	148	165
WPL [Member] | Other Postretirement Benefits Plans [Member]
Amounts recognized on the balance sheets consist of:
Non-current assets	4	3
Current liabilities	(6)	(5)
Pension and other benefit obligations	(45)	(49)
Net amounts recognized at December 31	(47)	(51)
Amounts recognized in Regulatory Assets consist of:
Net actuarial loss	3	6
Prior service credit	0	0
Net amount recognized at December 31	$ 3	$ 6