| Standard label: | Sale and Total Return Swap [Member] | 
| Name: | us-gaap:SaleAndTotalReturnSwapMember | 
| Documentation: | Swap agreement in which one party makes payments based on a set rate while the other party makes payments based on the return of an underlying asset. | 
| Object type: | cm:Member | 
| Data type: | [Member] (nonnum:domainItemType) | 
| Period type: | For Period (duration) | 
| Balance type: | (no balance type) | 
| Abstract: | true | 
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:SaleAndTotalReturnSwapMember | 
| Label | Role | Language | 
| Sale and Total Return Swap [Member] | http://www.xbrl.org/2003/role/label | en-US | 
| Reference | Role | Topic |