cm:Concept: us-gaap:OtherComprehensiveIncomeDerivativesQualifyingAsHedgesBeforeTaxPortionAttributableToNoncontrollingInterest
| Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, before Tax, Portion Attributable to Noncontrolling Interest |
| us-gaap:OtherComprehensiveIncomeDerivativesQualifyingAsHedgesBeforeTaxPortionAttributableToNoncontrollingInterest |
| Amount before tax, after reclassification adjustments, of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss), attributable to noncontrolling interests. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Debit |
| false |
| us-gaap:OtherComprehensiveIncomeDerivativesQualifyingAsHedgesBeforeTaxPortionAttributableToNoncontrollingInterest |