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Jointly-owned Plant Schedule of Jointly-owned plant (Details) $ in Millions | Dec. 31, 2024 USD ($)
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Jointly Owned Utility Plant Interests [Line Items] |
Jointly Owned Utility Plant, Gross Ownership Amount of Plant in Service | $ 797
Jointly Owned Utility Plant, Ownership Amount of Plant Accumulated Depreciation | 565
Jointly Owned Utility Plant, Ownership Amount of Construction Work in Progress | 25
Colstrip [Member] |
Jointly Owned Utility Plant Interests [Line Items] |
Jointly Owned Utility Plant, Gross Ownership Amount of Plant in Service | 507
Jointly Owned Utility Plant, Ownership Amount of Plant Accumulated Depreciation | 449
Jointly Owned Utility Plant, Ownership Amount of Construction Work in Progress | 5
Pelton/Round Butte Member |
Jointly Owned Utility Plant Interests [Line Items] |
Jointly Owned Utility Plant, Gross Ownership Amount of Plant in Service | 221
Jointly Owned Utility Plant, Ownership Amount of Plant Accumulated Depreciation | 76
Jointly Owned Utility Plant, Ownership Amount of Construction Work in Progress | 20
Colstrip - Transmission |
Jointly Owned Utility Plant Interests [Line Items] |
Jointly Owned Utility Plant, Gross Ownership Amount of Plant in Service | 69
Jointly Owned Utility Plant, Ownership Amount of Plant Accumulated Depreciation | 40
Jointly Owned Utility Plant, Ownership Amount of Construction Work in Progress | $ 0

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- Definition The period end amount owned by the reporting utility of a jointly owned utility plant in service. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 980 -SubTopic 360 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 10.C) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479070/980-360-S99-1 + Details
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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 No definition available. + Details
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- Definition The period end amount of construction work in progress at a jointly owned electricity generation plant. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 980 -SubTopic 360 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 10.C) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479070/980-360-S99-1 + Details
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- Definition The period end amount of accumulated depreciation in a jointly owned electricity generation plant. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 980 -SubTopic 360 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 10.C) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479070/980-360-S99-1 + Details
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