cm:Concept: us-gaap:InterestRateDerivativesAtFairValueNet
| Interest Rate Derivatives, at Fair Value, Net |
| us-gaap:InterestRateDerivativesAtFairValueNet |
| Fair value as of the balance sheet date of interest rate derivative assets, net of interest rate derivative liabilities, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized on the balance sheet. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Debit |
| false |
| us-gaap:InterestRateDerivativesAtFairValueNet |