| Standard label: | Jointly Owned Utility Plant, Ownership Amount of Plant Accumulated Depreciation |
| Name: | us-gaap:JointlyOwnedUtilityPlantOwnershipAmountOfPlantAccumulatedDepreciation |
| Documentation: | The period end amount of accumulated depreciation in a jointly owned electricity generation plant. |
| Object type: | cm:Concept |
| Data type: | Monetary (xbrli:monetaryItemType) |
| Period type: | As Of (instant) |
| Balance type: | Credit |
| Abstract: | false |
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:JointlyOwnedUtilityPlantOwnershipAmountOfPlantAccumulatedDepreciation |
| Label | Role | Language |
| Jointly Owned Utility Plant, Ownership Amount of Plant Accumulated Depreciation | http://www.xbrl.org/2003/role/label | en-US |
| Jointly Owned Utility Plant, Ownership Amount of Plant Accumulated Depreciation, Total | http://www.xbrl.org/2003/role/totalLabel | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 980 360 S99 1 (SAB Topic 10.C) | http://fasb.org/us-gaap/role/ref/legacyRef | 980 |