cm:Concept: us-gaap:DerivativeNonmonetaryNotionalAmountPercentOfRequiredNeedCoverage
| Derivative, Nonmonetary Notional Amount, Percent of Required Need, Coverage |
| us-gaap:DerivativeNonmonetaryNotionalAmountPercentOfRequiredNeedCoverage |
| The percentage of expected requirements covered by the aggregate notional amount of derivative contracts expressed in nonmonetary units. For example, the number of barrels specified in a fuel oil forward purchase contract as a percentage of expected need. |
| cm:Concept |
| Percent (num:percentItemType) |
| As Of (instant) |
| (no balance type) |
| false |
| us-gaap:DerivativeNonmonetaryNotionalAmountPercentOfRequiredNeedCoverage |