cm:Concept: us-gaap:PhaseInPlanAmountOfCostsDeferredForRateMakingPurposes
| Phase-in Plan, Amount of Costs Deferred for Rate-making Purposes |
| us-gaap:PhaseInPlanAmountOfCostsDeferredForRateMakingPurposes |
| The total amount of allowable costs capitalized during the period by the entity pertaining to Phase-In plans which were deferred on the expectation of future recovery. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Debit |
| false |
| us-gaap:PhaseInPlanAmountOfCostsDeferredForRateMakingPurposes |