cm:Concept: us-gaap:DeferredPolicyAcquisitionCostsAndPresentValueOfFutureInsuranceProfitsDisposition
| Deferred Policy Acquisition Costs and Present Value of Future Insurance Profits, Disposition |
| us-gaap:DeferredPolicyAcquisitionCostsAndPresentValueOfFutureInsuranceProfitsDisposition |
| Amount of deferred policy acquisition costs and present value of future profits from insurance contract acquired in business combination, disposed or classified as held-for-sale. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Credit |
| false |
| us-gaap:DeferredPolicyAcquisitionCostsAndPresentValueOfFutureInsuranceProfitsDisposition |