cm:Concept: us-gaap:IncrementalCommonSharesAttributableToAcceleratedShareRepurchaseAgreements
| Incremental Common Shares Attributable to Dilutive Effect of Accelerated Share Repurchase Agreements |
| us-gaap:IncrementalCommonSharesAttributableToAcceleratedShareRepurchaseAgreements |
| Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of accelerated share repurchase agreements. An accelerated share repurchase program is a combination of transactions that permits an entity to purchase a targeted number of shares immediately with the final purchase price of those shares determined by an average market price over a fixed period of time. |
| cm:Concept |
| Shares (xbrli:sharesItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:IncrementalCommonSharesAttributableToAcceleratedShareRepurchaseAgreements |