| Standard label: | Decommissioning Trust Assets Description |
| Name: | us-gaap:DecommissioningTrustAssetsDescription |
| Documentation: | Describes decommissioning trust assets. May include disclosures such as the purpose of the funds, funding requirements, regulatory authorities and related cost recovery aspects. |
| Object type: | cm:Concept |
| Data type: | Text/String (xbrli:stringItemType) |
| Period type: | For Period (duration) |
| Balance type: | (no balance type) |
| Abstract: | false |
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:DecommissioningTrustAssetsDescription |
| Label | Role | Language |
| Decommissioning Trust Assets Description | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 410 20 50 1 (a) | http://fasb.org/us-gaap/role/ref/legacyRef | 410 |