cm:Level1TextBlock: us-gaap:DisclosureOfReclassificationAmountTextBlock
| Disclosure of Reclassification Amount [Text Block] |
| us-gaap:DisclosureOfReclassificationAmountTextBlock |
| The entire disclosure for any adjustments made during the period to avoid double counting in comprehensive income items displayed as part of net income that also had been displayed as part of other comprehensive income in that period or earlier periods. These adjustments include reclassifications to net income of items in accumulated comprehensive income, such as deferred gains or losses on qualifying hedges when hedged item reported in net income, holding gains or losses on available-for-sale securities transferred into trading category, unrealized holding gains or losses on debt securities transferred from held-to-maturity category into available-for-sale category and accumulated translation adjustment attributable to foreign subsidiary or investment in foreign entity upon sale or liquidation. |
| cm:Level1TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:DisclosureOfReclassificationAmountTextBlock |
| ReclassificationAmountDisclosure |