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Commitments, Contingencies and Guarantees (Details) a in Millions, $ in Millions |  | 3 Months Ended
--- | --- | ---
Apr. 13, 2022 USD ($) a | Sep. 30, 2023 USD ($)
Loss Contingencies [Line Items] |  |
Gain on Business Interruption Insurance Recovery, Statement of Income or Comprehensive Income [Extensible Enumeration] |  | Revenues
Black Hills Wyoming and Wyodak Resources Development Corporation |  |
Loss Contingencies [Line Items] |  |
Business interruption insurance recovered |  | $ 5.0
GT Resources, LLC | Pending Litigation |  |
Loss Contingencies [Line Items] |  |
Loss Contingency, Damages Awarded, Value | $ 41.0 |
Loss Contingency, Concession Award, Area | a | 2.3 |

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- Definition The net amount (to the extent disclosed within this portion of the income statement) by which an insurance settlement exceeds incremental costs incurred from the event causing an interruption of business, plus the insurance award for earnings lost from the event, such as a natural catastrophe, explosion or fire. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 220 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147483605/220-30-50-1 + Details
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