cm:Level3TextBlock: us-gaap:ScheduleOfNetInvestmentHedgesInAccumulatedOtherComprehensiveIncomeLossTableTextBlock
| Schedule of Net Investment Hedges in Accumulated Other Comprehensive Income (Loss) [Table Text Block] |
| us-gaap:ScheduleOfNetInvestmentHedgesInAccumulatedOtherComprehensiveIncomeLossTableTextBlock |
| Tabular disclosure of the effective portion of gains and losses on derivative instruments (and nonderivative instruments) designated and qualifying in net investment hedges recorded in accumulated other comprehensive income (loss) during the term of the hedging relationship and reclassified into earnings during the current period. |
| cm:Level3TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:ScheduleOfNetInvestmentHedgesInAccumulatedOtherComprehensiveIncomeLossTableTextBlock |