cm:Concept: us-gaap:PaymentsForProceedsFromDerivativeInstrumentInvestingActivities
| Payments for (Proceeds from) Derivative Instrument, Investing Activities |
| us-gaap:PaymentsForProceedsFromDerivativeInstrumentInvestingActivities |
| The net cash outflow or inflow from derivative instruments during the period, which are classified as investing activities, excluding those designated as hedging instruments. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Credit |
| false |
| us-gaap:PaymentsForProceedsFromDerivativeInstrumentInvestingActivities |