cm:Concept: us-gaap:DescriptionOfTypesOfCashFlowHedgingInstrumentsUsed
| Description of Types of Cash Flow Hedging Instruments Used |
| us-gaap:DescriptionOfTypesOfCashFlowHedgingInstrumentsUsed |
| Description of the types of derivative instruments designated as cash flow hedging instruments. For example, interest rate swaps, forward contracts, and so forth. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:DescriptionOfTypesOfCashFlowHedgingInstrumentsUsed |