cm:Level1TextBlock: us-gaap:LiabilityForFuturePolicyBenefitsAndUnpaidClaimsDisclosureTextBlock
| Liability for Future Policy Benefits and Unpaid Claims Disclosure [Text Block] |
| us-gaap:LiabilityForFuturePolicyBenefitsAndUnpaidClaimsDisclosureTextBlock |
| The entire disclosure for liabilities related to future policy benefits and unpaid claims and claim adjustments. |
| cm:Level1TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:LiabilityForFuturePolicyBenefitsAndUnpaidClaimsDisclosureTextBlock |