cm:Level3TextBlock: us-gaap:ScheduleOfOtherOperatingCostAndExpenseByComponentTextBlock
| Schedule of Other Operating Cost and Expense, by Component [Table Text Block] |
| us-gaap:ScheduleOfOtherOperatingCostAndExpenseByComponentTextBlock |
| Tabular disclosure of each detailed component of other operating costs and expenses that are applicable to sales and revenues, but not included in the cost of sales in the income statement. |
| cm:Level3TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:ScheduleOfOtherOperatingCostAndExpenseByComponentTextBlock |
| OtherOperatingIncomeAndExpenseRollUp |