Property, Plant and Equipment (Property, Plant and Equipment) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Electric plant anticipated to be retired early	$ 2,094	$ 1,269
Total electric plant	16,710	16,243
Gas plant in service	1,636	1,563
Other plant in service	621	534
Accumulated depreciation	(5,263)	(4,868)
Net plant	13,704	13,472
Leased land for solar generation, net	11	0
Construction work in progress	778	405
Other, net	7	7
Total utility	14,500	13,884
Non-utility Generation, net	75	79
Corporate Services and other, net	412	373
Total non-utility and other	487	452
Total property, plant and equipment	14,987	14,336
Non-utility Generation, accumulated depreciation	67	63
Corporate Services and other, accumulated depreciation	245	210
Generation [Member]
Property, Plant and Equipment [Line Items]
Electric plant in service	7,539	8,222
Distribution [Member]
Property, Plant and Equipment [Line Items]
Electric plant in service	6,537	6,216
Other [Member]
Property, Plant and Equipment [Line Items]
Electric plant in service	540	536
IPL [Member]
Property, Plant and Equipment [Line Items]
Electric plant anticipated to be retired early	487	459
Total electric plant	9,424	9,171
Gas plant in service	878	844
Other plant in service	398	354
Accumulated depreciation	(2,897)	(2,671)
Net plant	7,803	7,698
Construction work in progress	174	185
Other, net	6	6
Total utility	7,983	7,889
Total property, plant and equipment	7,983	7,889
IPL [Member] | Lansing [Member]
Property, Plant and Equipment [Line Items]
Electric plant anticipated to be retired early	245
IPL [Member] | Generation [Member]
Property, Plant and Equipment [Line Items]
Electric plant in service	4,922	4,884
IPL [Member] | Distribution [Member]
Property, Plant and Equipment [Line Items]
Electric plant in service	3,652	3,470
IPL [Member] | Other [Member]
Property, Plant and Equipment [Line Items]
Electric plant in service	363	358
WPL [Member]
Property, Plant and Equipment [Line Items]
Electric plant anticipated to be retired early	1,607	810
Total electric plant	7,286	7,072
Gas plant in service	758	719
Other plant in service	223	180
Accumulated depreciation	(2,366)	(2,197)
Net plant	5,901	5,774
Leased Sheboygan Falls Energy Facility, net	21	27
Leased land for solar generation, net	11	0
Construction work in progress	604	220
Other, net	1	1
Total utility	6,538	6,022
Total property, plant and equipment	6,538	6,022
Leased Sheboygan Falls Energy Facility, accumulated depreciation	100	95
WPL [Member] | Edgewater Unit 5 [Member]
Property, Plant and Equipment [Line Items]
Electric plant anticipated to be retired early	527
WPL [Member] | Columbia Units 1 And 2 [Member]
Property, Plant and Equipment [Line Items]
Electric plant anticipated to be retired early	460
WPL [Member] | Generation [Member]
Property, Plant and Equipment [Line Items]
Electric plant in service	2,617	3,338
WPL [Member] | Distribution [Member]
Property, Plant and Equipment [Line Items]
Electric plant in service	2,885	2,746
WPL [Member] | Other [Member]
Property, Plant and Equipment [Line Items]
Electric plant in service	$ 177	$ 178