cm:Concept: us-gaap:DerivativeNetLiabilityPositionAggregateFairValue
| Derivative, Net Liability Position, Aggregate Fair Value |
| us-gaap:DerivativeNetLiabilityPositionAggregateFairValue |
| The aggregate fair value amounts of derivative instruments that contain credit-risk-related contingent features that are in a net liability position at the end of the reporting period. For nonderivative instruments that are designated and qualify as hedging instruments, the fair value amounts are the carrying value of the nonderivative hedging instrument, including the adjustment for the foreign currency transaction gain (loss) on that instrument. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Credit |
| false |
| us-gaap:DerivativeNetLiabilityPositionAggregateFairValue |