cm:Concept: us-gaap:AssetRecoveryDamagedPropertyCostsNoncurrent
| Asset Recovery Damaged Property Costs, Noncurrent |
| us-gaap:AssetRecoveryDamagedPropertyCostsNoncurrent |
| Carrying amount as of the balance sheet date of the portion of the reserved funds established by a utility from customer payments to cover the repair costs of damages from major storms, which repairs are expected to be incurred beyond one year or the normal operating cycle, if longer. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Debit |
| false |
| us-gaap:AssetRecoveryDamagedPropertyCostsNoncurrent |