Property, Plant and Equipment (Property, Plant and Equipment) (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Electric plant anticipated to be retired early	$ 2,103	$ 2,094
Total electric plant	17,618	16,710
Gas plant in service	1,705	1,636
Other plant in service	624	621
Accumulated depreciation	(5,690)	(5,263)
Net plant	14,257	13,704
Leased land for solar generation, net	133	11
Construction work in progress	1,357	778
Other, net	6	7
Total utility	15,753	14,500
Non-utility Generation, net	71	75
Corporate Services and other, net	423	412
Total non-utility and other	494	487
Total property, plant and equipment	16,247	14,987
Non-utility Generation, accumulated depreciation	71	67
Corporate Services and other, accumulated depreciation	269	245
Generation [Member]
Property, Plant and Equipment [Line Items]
Electric plant in service	8,060	7,539
Distribution [Member]
Property, Plant and Equipment [Line Items]
Electric plant in service	6,912	6,537
Other [Member]
Property, Plant and Equipment [Line Items]
Electric plant in service	543	540
IPL [Member]
Property, Plant and Equipment [Line Items]
Electric plant anticipated to be retired early	491	487
Total electric plant	9,683	9,424
Gas plant in service	910	878
Other plant in service	402	398
Accumulated depreciation	(3,149)	(2,897)
Net plant	7,846	7,803
Leased land for solar generation, net	0	0
Construction work in progress	194	174
Other, net	6	6
Total utility	8,046	7,983
Total property, plant and equipment	8,046	7,983
IPL [Member] | Lansing [Member]
Property, Plant and Equipment [Line Items]
Electric plant anticipated to be retired early	233
IPL [Member] | Generation [Member]
Property, Plant and Equipment [Line Items]
Electric plant in service	4,962	4,922
IPL [Member] | Distribution [Member]
Property, Plant and Equipment [Line Items]
Electric plant in service	3,876	3,652
IPL [Member] | Other [Member]
Property, Plant and Equipment [Line Items]
Electric plant in service	354	363
WPL [Member]
Property, Plant and Equipment [Line Items]
Electric plant anticipated to be retired early	1,612	1,607
Total electric plant	7,935	7,286
Gas plant in service	795	758
Other plant in service	222	223
Accumulated depreciation	(2,541)	(2,366)
Net plant	6,411	5,901
Leased Sheboygan Falls Energy Facility, net	15	21
Leased land for solar generation, net	133	11
Construction work in progress	1,163	604
Other, net	0	1
Total utility	7,722	6,538
Total property, plant and equipment	7,722	6,538
Leased Sheboygan Falls Energy Facility, accumulated depreciation	106	100
WPL [Member] | Edgewater Unit 5 [Member]
Property, Plant and Equipment [Line Items]
Electric plant anticipated to be retired early	511
WPL [Member] | Columbia Units 1-2 [Member]
Property, Plant and Equipment [Line Items]
Electric plant anticipated to be retired early	440
WPL [Member] | Generation [Member]
Property, Plant and Equipment [Line Items]
Electric plant in service	3,098	2,617
WPL [Member] | Distribution [Member]
Property, Plant and Equipment [Line Items]
Electric plant in service	3,036	2,885
WPL [Member] | Other [Member]
Property, Plant and Equipment [Line Items]
Electric plant in service	$ 189	$ 177