cm:Level1TextBlock: us-gaap:DisposalGroupsIncludingDiscontinuedOperationsDisclosureTextBlock
| Disposal Groups, Including Discontinued Operations, Disclosure [Text Block] |
| us-gaap:DisposalGroupsIncludingDiscontinuedOperationsDisclosureTextBlock |
| The entire disclosure related to a disposal group. Includes, but is not limited to, a discontinued operation, disposal classified as held-for-sale or disposed of by means other than sale or disposal of an individually significant component. |
| cm:Level1TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:DisposalGroupsIncludingDiscontinuedOperationsDisclosureTextBlock |
| DisposalGroupsIncludingDiscontinuedOperationsDisclosure |