cm:Concept: us-gaap:RecordedThirdPartyEnvironmentalRecoveriesDiscountRate
| Recorded Third-Party Environmental Recoveries, Discount Rate |
| us-gaap:RecordedThirdPartyEnvironmentalRecoveriesDiscountRate |
| Rate applied to the undiscounted amount of the asset for third-party recoveries related to environmental remediation obligations to arrive at the present value recorded as of the balance sheet date. |
| cm:Concept |
| Percent (num:percentItemType) |
| As Of (instant) |
| (no balance type) |
| false |
| us-gaap:RecordedThirdPartyEnvironmentalRecoveriesDiscountRate |