cm:Concept: us-gaap:VariableInterestEntityFinancialOrOtherSupportAmount
| Variable Interest Entity, Financial or Other Support, Amount |
| us-gaap:VariableInterestEntityFinancialOrOtherSupportAmount |
| The amount of financial or other support the reporting entity has provided (explicitly or implicitly) to the Variable Interest Entity (VIE) that it was not previously contractually required to provide or that the reporting entity intends to provide, including, for example, situations in which the reporting entity assisted the VIE in obtaining another type of support. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Debit |
| false |
| us-gaap:VariableInterestEntityFinancialOrOtherSupportAmount |