cm:Concept: us-gaap:SecuritiesPurchasedUnderAgreementsToResellCounterpartyNameExtensibleList
| Securities Purchased under Agreements to Resell, Counterparty Name [Extensible List] |
| us-gaap:SecuritiesPurchasedUnderAgreementsToResellCounterpartyNameExtensibleList |
| Indicates name of counterparty to security purchased under agreement to resell. Counterparty is other party participating in financial transaction. Example includes, but is not limited to, name of financial institution. |
| cm:Concept |
| srt-types:extensibleListItemType |
| As Of (instant) |
| (no balance type) |
| false |
| us-gaap:SecuritiesPurchasedUnderAgreementsToResellCounterpartyNameExtensibleList |