cm:Concept: us-gaap:RepaymentsOfMandatoryRedeemableCapitalSecurities
| Repayments of Mandatory Redeemable Capital Securities |
| us-gaap:RepaymentsOfMandatoryRedeemableCapitalSecurities |
| The cash outflow related to equity securities that embody an unconditional obligation requiring the issuer to redeem the securities by transferring the assets at a specified or determinable date (or dates) that is (or are) initially more than one year (or the normal operating cycle, if longer) from the issuance date, or upon an event that is certain to occur beyond one year (or the normal operating cycle, if longer) from the issuance date. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Credit |
| false |
| us-gaap:RepaymentsOfMandatoryRedeemableCapitalSecurities |