cm:Table: us-gaap:SecuritizationFinancialAssetForWhichTransferIsAccountedAsSaleTable
       
          
          | Schedule of Securitization or Asset-backed Financing Arrangements, Financial Asset for which Transfer is Accounted as Sale [Table] | 
       
       
          
          | us-gaap:SecuritizationFinancialAssetForWhichTransferIsAccountedAsSaleTable | 
       
       
          
          | The gains or losses by type of financial asset in a securitization, asset-backed financing arrangement, or similar transfer recognized when a transfer is accounted for as a sale. | 
       
       
          
          | cm:Table | 
       
       
          
          | Text/String (xbrli:stringItemType) | 
       
       
          
          | For Period (duration) | 
       
       
          
          | (no balance type) | 
       
       
          
          | true | 
       
       
          
          | us-gaap:SecuritizationFinancialAssetForWhichTransferIsAccountedAsSaleTable |