cm:Concept: us-gaap:GuaranteeObligationsCollateralHeldDirectlyOrByThirdParties
| Guarantor Obligations, Collateral Held Directly or by Third Parties |
| us-gaap:GuaranteeObligationsCollateralHeldDirectlyOrByThirdParties |
| Describes the nature of any assets held either as collateral or by third parties that, upon the occurrence of any triggering event or condition under the guarantee, the guarantor can obtain and liquidate to recover all or a portion of the amounts paid under the guarantee. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:GuaranteeObligationsCollateralHeldDirectlyOrByThirdParties |