cm:Axis: us-gaap:AssetsSoldUnderAgreementsToRepurchaseAxis
| Securities or Other Assets Sold under Agreements to Repurchase [Axis] |
| us-gaap:AssetsSoldUnderAgreementsToRepurchaseAxis |
| Information by securities or other assets sold under repurchase agreements. Repurchase agreements are agreements under which the transferor (repo party) transfers a security to a transferee (repo counterparty or reverse party) in exchange for cash and concurrently agrees to reacquire that security at a future date for an amount equal to the cash exchanged plus a stipulated interest factor. |
| cm:Axis |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| true |
| us-gaap:AssetsSoldUnderAgreementsToRepurchaseAxis |