cm:Concept: us-gaap:LongTermContractForPurchaseOfElectricPowerEstimatedAnnualCost
| Long-term Contract for Purchase of Electric Power, Estimated Annual Cost |
| us-gaap:LongTermContractForPurchaseOfElectricPowerEstimatedAnnualCost |
| Estimated annual cost to purchase electricity under a long-term contract from a production plant constructed and financed by a public utility district, cooperative, or other organization. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Debit |
| false |
| us-gaap:LongTermContractForPurchaseOfElectricPowerEstimatedAnnualCost |