cm:Concept: us-gaap:LongDurationContractsAssumptionsByProductAndGuaranteeMortalityRate
| Long-Duration Contracts, Assumptions by Product and Guarantee, Mortality Rate |
| us-gaap:LongDurationContractsAssumptionsByProductAndGuaranteeMortalityRate |
| Actuarially determined death rate of policyholders, which is included in determining 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:LongDurationContractsAssumptionsByProductAndGuaranteeMortalityRate |