cm:Concept: us-gaap:PhaseInPlanAmountOfCapitalizedCostsRecovered
| Phase-in Plan, Amount of Capitalized Costs Recovered |
| us-gaap:PhaseInPlanAmountOfCapitalizedCostsRecovered |
| The sum total amount of allowable costs capitalized in the period pertaining to a phase-in plan and previously capitalized costs that were recovered (recognized in earnings) during the period through rates. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Credit |
| false |
| us-gaap:PhaseInPlanAmountOfCapitalizedCostsRecovered |