cm:Concept: us-gaap:LiabilityForFuturePolicyBenefitExpectedFuturePolicyBenefitUndiscountedBeforeReinsurance
| Liability for Future Policy Benefit, Expected Future Policy Benefit, Undiscounted, before Reinsurance |
| us-gaap:LiabilityForFuturePolicyBenefitExpectedFuturePolicyBenefitUndiscountedBeforeReinsurance |
| Amount, before effect of reinsurance, of undiscounted balance for expected future policy benefit and expense component of liability for future policy benefit. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Credit |
| false |
| us-gaap:LiabilityForFuturePolicyBenefitExpectedFuturePolicyBenefitUndiscountedBeforeReinsurance |