cm:Level3TextBlock: us-gaap:ScheduleOfEntityWideDisclosureOnGeographicAreasLongLivedAssetsInIndividualForeignCountriesByCountryTextBlock
| Schedule of Disclosure on Geographic Areas, Long-Lived Assets in Individual Foreign Countries by Country [Table Text Block] |
| us-gaap:ScheduleOfEntityWideDisclosureOnGeographicAreasLongLivedAssetsInIndividualForeignCountriesByCountryTextBlock |
| Tabular disclosure of the names of foreign countries in which material long-lived assets other than financial instruments, long-term customer relationships of a financial institution, mortgage and other servicing rights, deferred policy acquisition costs, and deferred tax assets are located, and amount of such long-lived assets located in that country or foreign geographic area. |
| cm:Level3TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:ScheduleOfEntityWideDisclosureOnGeographicAreasLongLivedAssetsInIndividualForeignCountriesByCountryTextBlock |
| GeographicAreasLongLivedAssetsInIndividualForeignCountriesByCountryDisclosure |