| Standard label: | Amortization of Rate Deferral |
| Name: | us-gaap:AmortizationOfRateDeferral |
| Documentation: | The periodic expense to reduce the value of the rate deferral asset that is created when utilities under bill customers during periods of rate increases by deferring rate increases. These customers eventually pay higher rates to repay the utility for the rate deferral. |
| 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:AmortizationOfRateDeferral |
| Label | Role | Language |
| Amortization of Rate Deferral | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 230 10 45 28 (b) | http://fasb.org/us-gaap/role/ref/legacyRef | 230 |
| Part Of Roll Up: |
| us-gaap:AmortizationOfDeferredCharges |
| us-gaap:AdjustmentForAmortization |