cm:Concept: us-gaap:DeferredPolicyAcquisitionCostAndPresentValueOfFutureInsuranceProfitSegmentExtensibleList
| Deferred Policy Acquisition Cost and Present Value of Future Insurance Profit, Segment [Extensible List] |
| us-gaap:DeferredPolicyAcquisitionCostAndPresentValueOfFutureInsuranceProfitSegmentExtensibleList |
| Indicates business segment for deferred policy acquisition cost and present value of future insurance profit. |
| cm:Concept |
| srt-types:extensibleListItemType |
| As Of (instant) |
| (no balance type) |
| false |
| us-gaap:DeferredPolicyAcquisitionCostAndPresentValueOfFutureInsuranceProfitSegmentExtensibleList |