| Standard label: | Guaranty Liabilities |
| Name: | us-gaap:GuarantyLiabilities |
| Documentation: | This item represents a non-contingent liability for the fair value of an obligation to stand ready to perform over the term of a guaranty issued in the event that specified triggering events or conditions occur. |
| Object type: | cm:Concept |
| Data type: | Monetary (xbrli:monetaryItemType) |
| Period type: | As Of (instant) |
| Balance type: | Credit |
| Abstract: | false |
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:GuarantyLiabilities |
| Label | Role | Language |
| Guaranty Liabilities | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 460 10 25 3 | http://fasb.org/us-gaap/role/ref/legacyRef | 460 |
| FASB Accounting Standards Codification 460 10 25 4 | http://fasb.org/us-gaap/role/ref/legacyRef | 460 |
| FASB Accounting Standards Codification 942 210 S99 1 (SX 210.9-03.15) | http://fasb.org/us-gaap/role/ref/legacyRef | 942 |
| FASB Accounting Standards Codification 944 210 S99 1 (SX 210.7-03.15) | http://fasb.org/us-gaap/role/ref/legacyRef | 944 |