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Property, Plant and Equipment (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2021 | Dec. 31, 2020
Property, Plant and Equipment [Line Items] |  |
Property, plant and equipment | $ 7,856,573 | $ 7,305,530
Less accumulated depreciation and depletion | (1,407,397) | (1,285,816)
Property, plant and equipment of variable interest entities, net | 6,449,176 | 6,019,714
Corporate, Non-Segment |  |
Property, Plant and Equipment [Line Items] |  |
Property, Plant and Equipment | 5,694 | 5,692
Construction in progress, gross | 8,460 | 16,402
Property, plant and equipment | 14,154 | 22,094
Less accumulated depreciation and depletion | (1,544) | (1,144)
Property, plant and equipment of variable interest entities, net | $ 12,610 | $ 20,950
Weighted Average | Corporate, Non-Segment |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 10 years | 10 years
Minimum | Corporate, Non-Segment |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 10 years | 10 years
Maximum | Corporate, Non-Segment |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 22 years | 22 years
Electric Utilities |  |
Property, Plant and Equipment [Line Items] |  |
Total plant in service before construction work in progress | $ 3,991,095 | $ 3,875,557
Construction work in progress | 181,451 | 95,266
Property, plant and equipment | 4,172,546 | 3,970,823
Less accumulated depreciation and depletion | (1,016,738) | (960,993)
Property, plant and equipment of variable interest entities, net | $ 3,155,808 | 3,009,830
Depreciation, depletion and amortization, remaining amortization period | 9 years |
Electric Utilities | Production, Electric |  |
Property, Plant and Equipment [Line Items] |  |
Production, processing and storage | $ 1,452,055 | $ 1,417,951
Electric Utilities | Production, Electric | Weighted Average |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 41 years | 40 years
Electric Utilities | Production, Electric | Minimum |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 32 years |
Electric Utilities | Production, Electric | Maximum |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 45 years |
Electric Utilities | Electric transmission |  |
Property, Plant and Equipment [Line Items] |  |
Transmission | $ 546,126 | $ 517,794
Electric Utilities | Electric transmission | Weighted Average |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 49 years | 49 years
Electric Utilities | Electric transmission | Minimum |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 43 years |
Electric Utilities | Electric transmission | Maximum |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 50 years |
Electric Utilities | Electric distribution |  |
Property, Plant and Equipment [Line Items] |  |
Distribution | $ 1,000,619 | $ 959,453
Electric Utilities | Electric distribution | Weighted Average |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 47 years | 46 years
Electric Utilities | Electric distribution | Minimum |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 45 years |
Electric Utilities | Electric distribution | Maximum |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 49 years |
Electric Utilities | Integrated Generation |  |
Property, Plant and Equipment [Line Items] |  |
Plant acquisition adjustment | $ 720,490 | $ 716,479
Electric Utilities | Integrated Generation | Weighted Average |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 30 years | 31 years
Electric Utilities | Integrated Generation | Minimum |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 2 years |
Electric Utilities | Integrated Generation | Maximum |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 59 years |
Electric Utilities | Plant acquisition adjustment |  |
Property, Plant and Equipment [Line Items] |  |
Plant acquisition adjustment | $ 4,870 | $ 4,870
Electric Utilities | Plant acquisition adjustment | Weighted Average |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 32 years | 32 years
Electric Utilities | Plant acquisition adjustment | Minimum |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 32 years |
Electric Utilities | Plant acquisition adjustment | Maximum |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 32 years |
Electric Utilities | General |  |
Property, Plant and Equipment [Line Items] |  |
General | $ 266,935 | $ 259,010
Electric Utilities | General | Weighted Average |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 28 years | 28 years
Electric Utilities | General | Minimum |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 25 years |
Electric Utilities | General | Maximum |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 31 years |
Gas Utilities |  |
Property, Plant and Equipment [Line Items] |  |
Total plant in service before construction work in progress | $ 3,632,013 | $ 3,245,384
Construction work in progress | 37,860 | 67,229
Property, plant and equipment | 3,669,873 | 3,312,613
Less accumulated depreciation and depletion | (389,115) | (323,679)
Property, plant and equipment of variable interest entities, net | 3,280,758 | 2,988,934
Gas Utilities | Production, Gas |  |
Property, Plant and Equipment [Line Items] |  |
Production, processing and storage | $ 14,841 | $ 15,603
Gas Utilities | Production, Gas | Weighted Average |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 40 years | 40 years
Gas Utilities | Production, Gas | Minimum |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 24 years |
Gas Utilities | Production, Gas | Maximum |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 46 years |
Gas Utilities | Gas transmission |  |
Property, Plant and Equipment [Line Items] |  |
Transmission | $ 645,550 | $ 578,278
Gas Utilities | Gas transmission | Weighted Average |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 58 years | 54 years
Gas Utilities | Gas transmission | Minimum |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 22 years |
Gas Utilities | Gas transmission | Maximum |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 71 years |
Gas Utilities | Gas distribution |  |
Property, Plant and Equipment [Line Items] |  |
Distribution | $ 2,394,352 | $ 2,115,082
Gas Utilities | Gas distribution | Weighted Average |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 53 years | 53 years
Gas Utilities | Gas distribution | Minimum |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 45 years |
Gas Utilities | Gas distribution | Maximum |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 59 years |
Gas Utilities | Cushion gas - depreciable |  |
Property, Plant and Equipment [Line Items] |  |
Production, processing and storage | $ 3,539 | $ 3,539
Gas Utilities | Cushion gas - depreciable | Weighted Average |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 28 years | 28 years
Gas Utilities | Cushion gas - depreciable | Minimum |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 28 years |
Gas Utilities | Cushion gas - depreciable | Maximum |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 28 years |
Gas Utilities | Cushion gas - not depreciable |  |
Property, Plant and Equipment [Line Items] |  |
Production, processing and storage | $ 42,478 | $ 39,184
Gas Utilities | Gas, Storage |  |
Property, Plant and Equipment [Line Items] |  |
Production, processing and storage | $ 56,289 | $ 55,481
Gas Utilities | Gas, Storage | Weighted Average |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 38 years | 38 years
Gas Utilities | Gas, Storage | Minimum |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 27 years |
Gas Utilities | Gas, Storage | Maximum |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 52 years |
Gas Utilities | General |  |
Property, Plant and Equipment [Line Items] |  |
General | $ 474,964 | $ 438,217
Gas Utilities | General | Weighted Average |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 21 years | 19 years
Gas Utilities | General | Minimum |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 3 years |
Gas Utilities | General | Maximum |  |
Property, Plant and Equipment [Line Items] |  |
Weighted average useful life | 23 years |

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