cm:Level3TextBlock: us-gaap:ScheduleOfDebtTableTextBlock
| Schedule of Debt [Table Text Block] |
| us-gaap:ScheduleOfDebtTableTextBlock |
| Tabular disclosure of information pertaining to short-term and long-debt instruments or arrangements, including but not limited to identification of terms, features, collateral requirements and other information necessary to a fair presentation. |
| cm:Level3TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:ScheduleOfDebtTableTextBlock |
| Debt |