cm:Concept: us-gaap:DiscussionOfNetInvestmentHedgeEffectivenessAssessmentAndMeasurement
| Discussion of Net Investment Hedge Effectiveness Assessment and Measurement |
| us-gaap:DiscussionOfNetInvestmentHedgeEffectivenessAssessmentAndMeasurement |
| Discussion of how the entity assesses hedge effectiveness and measures hedge ineffectiveness of hedges of net investments in foreign operations. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:DiscussionOfNetInvestmentHedgeEffectivenessAssessmentAndMeasurement |