cm:Concept: us-gaap:DerivativeAssetSecuritiesPurchasedUnderAgreementsToResellSecuritiesBorrowed
| Derivative Asset, Securities Purchased under Agreements to Resell, Securities Borrowed |
| us-gaap:DerivativeAssetSecuritiesPurchasedUnderAgreementsToResellSecuritiesBorrowed |
| Amount, after the effects of master netting arrangements, of derivative assets, securities purchased under agreements to resell and securities borrowed. Includes assets not subject to a master netting arrangement and not elected to be offset. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Debit |
| false |
| us-gaap:DerivativeAssetSecuritiesPurchasedUnderAgreementsToResellSecuritiesBorrowed |