cm:Concept: us-gaap:TierOneLeverageCapitalRequiredToBeWellCapitalizedToAverageAssets
| Tier One Leverage Capital Required to be Well Capitalized to Average Assets |
| us-gaap:TierOneLeverageCapitalRequiredToBeWellCapitalizedToAverageAssets |
| The amount of Tier 1 Leverage Capital required to be categorized as well capitalized divided by average assets as defined in the regulatory framework for prompt corrective action. |
| cm:Concept |
| Percent (num:percentItemType) |
| As Of (instant) |
| (no balance type) |
| false |
| us-gaap:TierOneLeverageCapitalRequiredToBeWellCapitalizedToAverageAssets |