cm:Level1TextBlock: us-gaap:OtherIncomeAndOtherExpenseDisclosureTextBlock
| Other Income and Other Expense Disclosure [Text Block] |
| us-gaap:OtherIncomeAndOtherExpenseDisclosureTextBlock |
| The entire disclosure for other income or other expense items (both operating and nonoperating). Sources of nonoperating income or nonoperating expense that may be disclosed, include amounts earned from dividends, interest on securities, profits (losses) on securities, net and miscellaneous other income or income deductions. |
| cm:Level1TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:OtherIncomeAndOtherExpenseDisclosureTextBlock |
| OtherIncomeAndOtherExpenseDisclosure |