cm:Concept: us-gaap:AdditionalLiabilityLongDurationInsuranceReinsuranceRecoverableAfterAllowance
| Additional Liability, Long-Duration Insurance, Reinsurance Recoverable, after Allowance |
| us-gaap:AdditionalLiabilityLongDurationInsuranceReinsuranceRecoverableAfterAllowance |
| Amount, after allowance for credit loss, recoverable under reinsurance for 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 |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Debit |
| false |
| us-gaap:AdditionalLiabilityLongDurationInsuranceReinsuranceRecoverableAfterAllowance |