cm:Concept: us-gaap:DerivativeAssetFairValueGrossLiability
| Derivative Asset, Fair Value, Gross Liability |
| us-gaap:DerivativeAssetFairValueGrossLiability |
| Fair value of liability associated with financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Credit |
| false |
| us-gaap:DerivativeAssetFairValueGrossLiability |