cm:Concept: us-gaap:OtherComprehensiveIncomeDerivativesQualifyingAsHedgesNetOfTaxPortionAttributableToNoncontrollingInterest
| Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax, Portion Attributable to Noncontrolling Interest |
| us-gaap:OtherComprehensiveIncomeDerivativesQualifyingAsHedgesNetOfTaxPortionAttributableToNoncontrollingInterest |
| Amount after tax and 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:OtherComprehensiveIncomeDerivativesQualifyingAsHedgesNetOfTaxPortionAttributableToNoncontrollingInterest |