Property, Plant and Equipment (Property, Plant and Equipment) (Details) $ in Millions	Dec. 31, 2023 USD ($) MW	Dec. 31, 2022 USD ($)
Property, Plant and Equipment [Line Items]
Electric plant anticipated to be retired early	$ 1,629	$ 2,103
Total electric plant	18,690	17,618
Gas plant in service	1,791	1,705
Other plant in service	653	624
Accumulated depreciation	(5,924)	(5,690)
Net plant	15,210	14,257
Leased land for solar generation, net	172	133
Construction work in progress	1,245	1,357
Other, net	7	6
Total utility	16,634	15,753
Non-utility Generation, net	68	71
Corporate Services and other, net	455	423
Total non-utility and other	523	494
Total property, plant and equipment	17,157	16,247
Non-utility Generation, accumulated depreciation	75	71
Corporate Services and other, accumulated depreciation	275	269
Generation [Member]
Property, Plant and Equipment [Line Items]
Electric plant in service	9,180	8,060
Distribution [Member]
Property, Plant and Equipment [Line Items]
Electric plant in service	7,314	6,912
Other [Member]
Property, Plant and Equipment [Line Items]
Electric plant in service	567	543
IPL [Member]
Property, Plant and Equipment [Line Items]
Electric plant anticipated to be retired early	0	491
Total electric plant	9,472	9,683
Gas plant in service	951	910
Other plant in service	411	402
Accumulated depreciation	(3,180)	(3,149)
Net plant	7,654	7,846
Leased land for solar generation, net	33	0
Construction work in progress	605	194
Other, net	6	6
Total utility	8,298	8,046
Total property, plant and equipment	$ 8,298	8,046
Electric capacity of solar project | MW	400
Construction project cost target	$ 1,650
Construction project cost target exceedance, percentage	10.00%
IPL [Member] | Generation [Member]
Property, Plant and Equipment [Line Items]
Electric plant in service	$ 5,025	4,962
IPL [Member] | Distribution [Member]
Property, Plant and Equipment [Line Items]
Electric plant in service	4,091	3,876
IPL [Member] | Other [Member]
Property, Plant and Equipment [Line Items]
Electric plant in service	356	354
WPL [Member]
Property, Plant and Equipment [Line Items]
Electric plant anticipated to be retired early	1,629	1,612
Total electric plant	9,218	7,935
Gas plant in service	840	795
Other plant in service	242	222
Accumulated depreciation	(2,744)	(2,541)
Net plant	7,556	6,411
Leased Sheboygan Falls Energy Facility, net	79	15
Leased land for solar generation, net	139	133
Construction work in progress	640	1,163
Other, net	1	0
Total utility	8,415	7,722
Total property, plant and equipment	$ 8,415	7,722
Electric capacity of solar project | MW	1,100
Construction project cost target exceedance	$ 180
Leased Sheboygan Falls Energy Facility, accumulated depreciation	112	106
WPL [Member] | Edgewater Unit 5 [Member]
Property, Plant and Equipment [Line Items]
Electric plant anticipated to be retired early	504
WPL [Member] | Columbia Units 1-2 [Member]
Property, Plant and Equipment [Line Items]
Electric plant anticipated to be retired early	428
WPL [Member] | Generation [Member]
Property, Plant and Equipment [Line Items]
Electric plant in service	4,155	3,098
WPL [Member] | Distribution [Member]
Property, Plant and Equipment [Line Items]
Electric plant in service	3,223	3,036
WPL [Member] | Other [Member]
Property, Plant and Equipment [Line Items]
Electric plant in service	$ 211	$ 189