cm:Level3TextBlock: us-gaap:ScheduleOfCustomerSecuritiesForWhichEntityHasRightToSellOrRepledgeTextBlock
| Schedule of Customer Securities for which Entity has Right to Sell or Repledge [Table Text Block] |
| us-gaap:ScheduleOfCustomerSecuritiesForWhichEntityHasRightToSellOrRepledgeTextBlock |
| Tabular disclosure of customer securities accepted by the entity as collateral and re-pledged to counterparties as collateral or sold, including sources and uses of collateral, fair value of collateral and portion of that collateral that has been sold or re-pledged. |
| cm:Level3TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:ScheduleOfCustomerSecuritiesForWhichEntityHasRightToSellOrRepledgeTextBlock |