cm:Concept: us-gaap:DeconsolidationNatureOfContinuingInvolvementDescription
| Deconsolidation, Nature of Continuing Involvement, Description |
| us-gaap:DeconsolidationNatureOfContinuingInvolvementDescription |
| Description of nature of continuing involvement with former subsidiary and acquirer of group of assets constituting business or nonprofit activity deconsolidated and derecognized, excluding conveyance of oil and gas mineral rights and transfer of product or service in contract with customer. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:DeconsolidationNatureOfContinuingInvolvementDescription |