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Commitments, Contingencies and Guarantees: Power Sales Agreements (Details) - MW	Jun. 03, 2022	May 03, 2022
Wygen I I I Generating Facility Member
Unrecorded Unconditional Purchase Obligation [Line Items]
Jointly Owned Utility Plant, Proportionate Ownership Share		25.00%
M D U, Montana Dakota Utilities | South Dakota Electric
Unrecorded Unconditional Purchase Obligation [Line Items]
Number of Megawatts Sold Under Long-Term Contract	23
M D U, Montana Dakota Utilities | South Dakota Electric | Maximum
Unrecorded Unconditional Purchase Obligation [Line Items]
Number of Megawatts Sold Under Long-Term Contract		50

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- Definition

Number of Megawatts Sold Under Long-Term Contract

+ References

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- Definition

The proportionate share of interest (percent) in a jointly owned utility plant.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 980
-SubTopic 360
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 10.C)
-URI https://asc.fasb.org/extlink&oid=122136288&loc=d3e659983-123033

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

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