cm:Table: us-gaap:ScheduleOfAssetsAndAssociatedLiabilitiesAccountedForAsSecuredBorrowingsTable
       
          
          | Schedule of Assets and Associated Liabilities Accounted for as Secured Borrowings [Table] | 
       
       
          
          | us-gaap:ScheduleOfAssetsAndAssociatedLiabilitiesAccountedForAsSecuredBorrowingsTable | 
       
       
          
          | Information about the carrying amount and classification of assets and liabilities recognized in the transferor's statement of financial position at the end of each period presented. | 
       
       
          
          | cm:Table | 
       
       
          
          | Text/String (xbrli:stringItemType) | 
       
       
          
          | For Period (duration) | 
       
       
          
          | (no balance type) | 
       
       
          
          | true | 
       
       
          
          | us-gaap:ScheduleOfAssetsAndAssociatedLiabilitiesAccountedForAsSecuredBorrowingsTable |