cm:Concept: us-gaap:SiteContingencyEnvironmentalRemediationCostsRecognized
| Site Contingency, Environmental Remediation Costs Recognized |
| us-gaap:SiteContingencyEnvironmentalRemediationCostsRecognized |
| Description of costs recognized in the balance sheet and income statement in the period for known or estimated future costs arising from requirements to perform activities to remediate an individual site. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:SiteContingencyEnvironmentalRemediationCostsRecognized |