cm:Concept: us-gaap:ForeignCurrencyContractsLiabilityFairValueDisclosure
| Foreign Currency Contracts, Liability, Fair Value Disclosure |
| us-gaap:ForeignCurrencyContractsLiabilityFairValueDisclosure |
| Fair value portion of liability contracts related to the exchange of different currencies, including, but not limited to, foreign currency options, forward (delivery or nondelivery) contracts, and swaps entered into. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Credit |
| false |
| us-gaap:ForeignCurrencyContractsLiabilityFairValueDisclosure |