| Standard label: | Schedule of Credit Derivatives [Table] |
| Name: | us-gaap:ScheduleOfCreditDerivativesTable |
| Documentation: | Schedule of credit derivatives, including information about each credit derivative, or each group of similar credit derivatives, including (a) the nature of the credit derivative - its term, how it arose, the events or circumstances that would require the seller to perform under the credit derivative, and the current status of the payment/performance risk of the credit derivative; (b) the maximum potential amount of future payments (undiscounted) the seller could be required to make under the credit derivative; (c) the current fair value of the credit derivative; and (d) the nature of any recourse provisions under the credit derivative, and any assets held either as collateral or by third parties. |
| Object type: | cm:Table |
| Data type: | Text/String (xbrli:stringItemType) |
| Period type: | For Period (duration) |
| Balance type: | (no balance type) |
| Abstract: | true |
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:ScheduleOfCreditDerivativesTable |
| Label | Role | Language |
| Schedule of Credit Derivatives [Table] | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 815 10 50 4L | http://fasb.org/us-gaap/role/ref/legacyRef | 815 |
| FASB Accounting Standards Codification 815 10 50 4K | http://fasb.org/us-gaap/role/ref/legacyRef | 815 |
| FASB Accounting Standards Codification 815 10 50 4J | http://fasb.org/us-gaap/role/ref/legacyRef | 815 |