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Revenue: Disaggregation of Revenue (Details) - USD ($) $ in Thousands | 3 Months Ended
--- | ---
Mar. 31, 2022 | Mar. 31, 2021
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | $ 821,769 | $ 630,217
Total revenues | 823,570 | 633,432
Services transferred at a point in time |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 7,113 | 6,976
Services transferred over time |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 814,656 | 623,241
Other revenues |  |
Disaggregation of Revenue [Line Items] |  |
Total revenues | 1,801 | 3,215
Retail - Electric , Natural Gas and Coal |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 733,819 | 545,885
Transportation |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 49,424 | 47,841
Wholesale |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 10,275 | 11,359
Market - off-system sales |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 7,392 | 4,845
Transmission/Other |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 20,859 | 20,287
Inter-company Revenues |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | (4,248) | (4,399)
Total revenues | (4,360) | (4,491)
Inter-company Revenues | Services transferred at a point in time |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 0 | 0
Inter-company Revenues | Services transferred over time |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | (4,248) | (4,399)
Inter-company Revenues | Other revenues |  |
Disaggregation of Revenue [Line Items] |  |
Total revenues | (112) | (92)
Inter-company Revenues | Retail - Electric , Natural Gas and Coal |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 0 | 0
Inter-company Revenues | Transportation |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | (99) | (110)
Inter-company Revenues | Wholesale |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 0 | 0
Inter-company Revenues | Market - off-system sales |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 0 | 0
Inter-company Revenues | Transmission/Other |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | (4,149) | (4,289)
Electric Utilities |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 205,668 | 234,597
Total revenues | 206,538 | 235,404
Electric Utilities | Services transferred at a point in time |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 7,113 | 6,976
Electric Utilities | Services transferred over time |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 198,555 | 227,621
Electric Utilities | Other revenues |  |
Disaggregation of Revenue [Line Items] |  |
Total revenues | 870 | 807
Electric Utilities | Retail - Electric , Natural Gas and Coal |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 172,806 | 204,280
Electric Utilities | Transportation |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 0 | 0
Electric Utilities | Wholesale |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 10,275 | 11,359
Electric Utilities | Market - off-system sales |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 7,154 | 4,772
Electric Utilities | Transmission/Other |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 15,433 | 14,186
Gas Utilities |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 620,349 | 400,019
Total revenues | 621,392 | 402,519
Gas Utilities | Services transferred at a point in time |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 0 | 0
Gas Utilities | Services transferred over time |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 620,349 | 400,019
Gas Utilities | Other revenues |  |
Disaggregation of Revenue [Line Items] |  |
Total revenues | 1,043 | 2,500
Gas Utilities | Retail - Electric , Natural Gas and Coal |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 561,013 | 341,605
Gas Utilities | Transportation |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 49,523 | 47,951
Gas Utilities | Wholesale |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 0 | 0
Gas Utilities | Market - off-system sales |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 238 | 73
Gas Utilities | Transmission/Other |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | $ 9,575 | $ 10,390

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