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Operations and Significant Accounting Policies- Subsequent Events (Details) - Nemadji Trail Energy Center [Member] $ in Millions | Oct. 01, 2021 USD ($) | Sep. 30, 2021 USD ($) MW
--- | --- | ---
Subsequent Event [Line Items] |  |
Approximate Sales Price | $ 20.0 |
Estimated Capital Expenditures, Including Past Expenditures |  | $ 700.0
South Shore Energy |  |
Subsequent Event [Line Items] |  |
Gain on Sale after tax | 8.5 |
Development Costs Sold | $ 8.0 |
Estimated Capital Expenditures, Including Past Expenditures |  | 140.0
Total Project Costs Incurred to Date |  | $ 15.0
Natural Gas-fired [Member] |  |
Subsequent Event [Line Items] |  |
Generating Capacity to be Jointly Owned (MW) | MW |  | 600
Natural Gas-fired [Member] | Subsequent Event [Member] | Dairyland Power Cooperative |  |
Subsequent Event [Line Items] |  |
Expected Output Entitlement | 50.00% |
Natural Gas-fired [Member] | Subsequent Event [Member] | Basin Electric Power Cooperative |  |
Subsequent Event [Line Items] |  |
Expected Output Entitlement | 30.00% |
Natural Gas-fired [Member] | South Shore Energy | Subsequent Event [Member] |  |
Subsequent Event [Line Items] |  |
Expected Output Entitlement | 20.00% |

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- Definition Share of plant output being purchased under a long-term contract to purchase electricity from a production plant constructed and financed by a public utility district, cooperative, or other organization. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 10.D) -URI http://asc.fasb.org/extlink&oid=122136240&loc=d3e659339-123030 + Details
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- Definition Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event. + References No definition available. + Details
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- Details
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