cm:Member: us-gaap:PostemploymentRetirementBenefitsMember
| Postemployment Retirement Benefits [Member] |
| us-gaap:PostemploymentRetirementBenefitsMember |
| Special and contractual termination benefits provided in connection with termination of employment and payable upon retirement, but not payable from defined benefit plan. Excludes benefits payable upon termination from defined benefit pension and other postretirement plan, and postemployment benefits payable before retirement. |
| cm:Member |
| [Member] (nonnum:domainItemType) |
| For Period (duration) |
| (no balance type) |
| true |
| us-gaap:PostemploymentRetirementBenefitsMember |