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Property, Plant and Equipment (Property, Plant and Equipment) (Details) - USD ($) $ in Millions | Dec. 31, 2020 | Dec. 31, 2019
--- | --- | ---
Property, Plant and Equipment [Line Items] |  |
Electric plant anticipated to be retired early | $ 1,269 | $ 0
Total electric plant | 16,243 | 13,865
Gas plant in service | 1,563 | 1,463
Other plant in service | 534 | 520
Accumulated depreciation | (4,868) | (4,602)
Net plant | 13,472 | 11,246
Construction work in progress | 405 | 1,835
Other, net | 7 | 6
Total utility | 13,884 | 13,087
Non-utility Generation, net | 79 | 83
Corporate Services and other, net | 373 | 357
Total non-utility and other | 452 | 440
Total property, plant and equipment | 14,336 | 13,527
Non-utility Generation, accumulated depreciation | 63 | 59
Corporate Services and other, accumulated depreciation | 210 | 172
Generation [Member] |  |
Property, Plant and Equipment [Line Items] |  |
Electric plant in service | 8,222 | 7,625
Distribution [Member] |  |
Property, Plant and Equipment [Line Items] |  |
Electric plant in service | 6,216 | 5,783
Other [Member] |  |
Property, Plant and Equipment [Line Items] |  |
Electric plant in service | 536 | 457
IPL [Member] |  |
Property, Plant and Equipment [Line Items] |  |
Electric plant anticipated to be retired early | 459 | 0
Total electric plant | 9,171 | 7,921
Gas plant in service | 844 | 802
Other plant in service | 354 | 345
Accumulated depreciation | (2,671) | (2,499)
Net plant | 7,698 | 6,569
Construction work in progress | 185 | 907
Other, net | 6 | 5
Total utility | 7,889 | 7,481
Total property, plant and equipment | 7,889 | 7,481
IPL [Member] | Generation [Member] |  |
Property, Plant and Equipment [Line Items] |  |
Electric plant in service | 4,884 | 4,432
IPL [Member] | Distribution [Member] |  |
Property, Plant and Equipment [Line Items] |  |
Electric plant in service | 3,470 | 3,190
IPL [Member] | Other [Member] |  |
Property, Plant and Equipment [Line Items] |  |
Electric plant in service | 358 | 299
WPL [Member] |  |
Property, Plant and Equipment [Line Items] |  |
Electric plant anticipated to be retired early | 810 | 0
Total electric plant | 7,072 | 5,944
Gas plant in service | 719 | 661
Other plant in service | 180 | 175
Accumulated depreciation | (2,197) | (2,103)
Net plant | 5,774 | 4,677
Leased Sheboygan Falls Energy Facility, net | 27 | 32
Construction work in progress | 220 | 928
Other, net | 1 | 1
Total utility | 6,022 | 5,638
Total property, plant and equipment | 6,022 | 5,638
Leased Sheboygan Falls Energy Facility, accumulated depreciation | 95 | 89
WPL [Member] | Generation [Member] |  |
Property, Plant and Equipment [Line Items] |  |
Electric plant in service | 3,338 | 3,193
WPL [Member] | Distribution [Member] |  |
Property, Plant and Equipment [Line Items] |  |
Electric plant in service | 2,746 | 2,593
WPL [Member] | Other [Member] |  |
Property, Plant and Equipment [Line Items] |  |
Electric plant in service | $ 178 | $ 158

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