cm:Concept: us-gaap:OtherComprehensiveIncomeLossCashFlowHedgeReclassificationForDiscontinuanceBeforeTax
| Other Comprehensive Income (Loss), Cash Flow Hedge, Reclassification for Discontinuance, before Tax |
| us-gaap:OtherComprehensiveIncomeLossCashFlowHedgeReclassificationForDiscontinuanceBeforeTax |
| Amount, before tax, of reclassification from accumulated other comprehensive income (AOCI) for gain (loss) from discontinuance of cash flow hedge included in assessment of hedge effectiveness. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Debit |
| false |
| us-gaap:OtherComprehensiveIncomeLossCashFlowHedgeReclassificationForDiscontinuanceBeforeTax |