cm:Concept: us-gaap:DerivativeLiabilitySecuritiesSoldUnderAgreementsToResellSecuritiesLoaned
       
          
          | Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned | 
       
       
          
          | us-gaap:DerivativeLiabilitySecuritiesSoldUnderAgreementsToResellSecuritiesLoaned | 
       
       
          
          | Amount, after the effects of master netting arrangements, of derivative liabilities, securities sold under agreements to repurchase and securities loaned. Includes liabilities not subject to a master netting arrangement and not elected to be offset. | 
       
       
          
          | cm:Concept | 
       
       
          
          | Monetary (xbrli:monetaryItemType) | 
       
       
          
          | As Of (instant) | 
       
       
          
          | Credit | 
       
       
          
          | false | 
       
       
          
          | us-gaap:DerivativeLiabilitySecuritiesSoldUnderAgreementsToResellSecuritiesLoaned |