cm:Concept: us-gaap:LongDurationContractsAssumptionsByProductAndGuaranteeDiscountRate
| Long-Duration Contracts, Assumptions by Product and Guarantee, Discount Rate |
| us-gaap:LongDurationContractsAssumptionsByProductAndGuaranteeDiscountRate |
| Percentage discount rate used to calculate present value of an expected stream of future payments, which is included in the calculation of the amount of the specified guaranteed benefit obligation as of the balance sheet date. |
| cm:Concept |
| Percent (num:percentItemType) |
| As Of (instant) |
| (no balance type) |
| false |
| us-gaap:LongDurationContractsAssumptionsByProductAndGuaranteeDiscountRate |