cm:Concept: us-gaap:AllowanceForUncollectibleCustomersLiabilityForAcceptances
| Allowance for Uncollectible Customer's Liability for Acceptances |
| us-gaap:AllowanceForUncollectibleCustomersLiabilityForAcceptances |
| Represents the reserve against amounts due from customers which are uncollectible or questionable as to collection and which specifically relate to short-term negotiable time drafts drawn on and accepted by an institution (also known banker's acceptances). |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Credit |
| false |
| us-gaap:AllowanceForUncollectibleCustomersLiabilityForAcceptances |