cm:Concept: us-gaap:AdditionalLiabilityLongDurationInsuranceWeightedAverageInterestAccretionRate
| Additional Liability, Long-Duration Insurance, Weighted-Average Interest Accretion Rate |
| us-gaap:AdditionalLiabilityLongDurationInsuranceWeightedAverageInterestAccretionRate |
| Original weighted-average discount rate at contract issue date used to measure present value of total expected payment to policyholder in excess of present value of total expected assessment. Excludes benefit classified as market risk benefit or under provisions of Topic 815 on derivative and hedging. |
| cm:Concept |
| Percent (num:percentItemType) |
| As Of (instant) |
| (no balance type) |
| false |
| us-gaap:AdditionalLiabilityLongDurationInsuranceWeightedAverageInterestAccretionRate |