| Standard label: | Allowance for Funds Used During Construction, Investing Activities | 
| Name: | us-gaap:AllowanceForFundsUsedDuringConstructionInvestingActivities | 
| Documentation: | Cash inflow due to change during the period in the allowance for other funds used during construction classified as an investing activity. | 
| Object type: | cm:Concept | 
| Data type: | Monetary (xbrli:monetaryItemType) | 
| Period type: | For Period (duration) | 
| Balance type: | Debit | 
| Abstract: | false | 
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:AllowanceForFundsUsedDuringConstructionInvestingActivities | 
| Label | Role | Language | 
| Allowance for Funds Used During Construction, Investing Activities | http://www.xbrl.org/2003/role/label | en-US | 
| Reference | Role | Topic | 
| FASB Accounting Standards Codification 230 10 45 12 | http://fasb.org/us-gaap/role/ref/legacyRef | 230 | 
| FASB Accounting Standards Codification 980 360 25 1 | http://fasb.org/us-gaap/role/ref/legacyRef | 980 | 
| Part Of Roll Up: | 
| us-gaap:NetCashProvidedByUsedInInvestingActivitiesContinuingOperations |