cm:Concept: us-gaap:DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationWeightedAverageInterestCreditingRate
| Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Weighted-Average Interest Crediting Rate |
| us-gaap:DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationWeightedAverageInterestCreditingRate |
| Weighted-average interest crediting rate used to determine benefit obligation of defined benefit plan. Plan includes, but is not limited to, cash balance and other defined benefit plans with promised interest crediting rate. |
| cm:Concept |
| Percent (num:percentItemType) |
| As Of (instant) |
| (no balance type) |
| false |
| us-gaap:DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationWeightedAverageInterestCreditingRate |