| Standard label: | Schedule of Derivative Instruments [Table Text Block] | 
| Name: | us-gaap:ScheduleOfDerivativeInstrumentsTextBlock | 
| Documentation: | Tabular disclosure of pertinent information about a derivative or group of derivatives on a disaggregated basis, such as for individual instruments, or small groups of similar instruments. May include a combination of the type of instrument, risks being hedged, notional amount, hedge designation, related hedged item, inception date, maturity date, or other relevant item. | 
| Object type: | cm:Level3TextBlock | 
| Data type: | Text Block (HTML) (nonnum:textBlockItemType) | 
| Period type: | For Period (duration) | 
| Balance type: | (no balance type) | 
| Abstract: | false | 
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:ScheduleOfDerivativeInstrumentsTextBlock | 
| Label | Role | Language | 
| Schedule of Derivative Instruments [Table Text Block] | http://www.xbrl.org/2003/role/label | en-US |