cm:Level3TextBlock: us-gaap:ScheduleOfIntangibleAssetsAndGoodwillTableTextBlock
| Schedule of Intangible Assets and Goodwill [Table Text Block] |
| us-gaap:ScheduleOfIntangibleAssetsAndGoodwillTableTextBlock |
| Tabular disclosure of goodwill and intangible assets, which may be broken down by segment or major class. |
| cm:Level3TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:ScheduleOfIntangibleAssetsAndGoodwillTableTextBlock |
| IntangibleAssetsAndGoodwill |