cm:Concept: us-gaap:AociBeforeTaxAttributableToParent
| AOCI before Tax, Attributable to Parent |
| us-gaap:AociBeforeTaxAttributableToParent |
| Amount before tax of increase (decrease) in accumulated equity from transactions and other events and circumstances from non-owner sources, attributable to parent. Excludes net income (loss), and accumulated changes in equity from transactions resulting from investments by owners (distributions to owners). |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Credit |
| false |
| us-gaap:AociBeforeTaxAttributableToParent |