cm:Concept: us-gaap:ProceedsFromIssuanceOfMandatoryRedeemableCapitalSecurities
| Proceeds from Issuance of Mandatory Redeemable Capital Securities |
| us-gaap:ProceedsFromIssuanceOfMandatoryRedeemableCapitalSecurities |
| The cash inflow from issuance of an equity security that embodies an unconditional obligation requiring the issuer to redeem the security 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) |
| Debit |
| false |
| us-gaap:ProceedsFromIssuanceOfMandatoryRedeemableCapitalSecurities |