| Standard label: | US Treasury and Government [Member] |
| Name: | us-gaap:USTreasuryAndGovernmentMember |
| Documentation: | This category includes investments in debt securities issued by the United States Department of the Treasury, US Government Agencies and US Government-sponsored Enterprises. Such securities may include treasury bills (short-term maturities - one year or less), treasury notes (intermediate term maturities - two to ten years), and treasury bonds (long-term maturities - ten to thirty years), debt securities issued by the Government National Mortgage Association (Ginnie Mae) and debt securities issued by the Federal National Mortgage Association (Fannie Mae) or the Federal Home Loan Mortgage Corporation (Freddie Mac). |
| 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:USTreasuryAndGovernmentMember |
| Label | Role | Language |
| US Treasury and Government [Member] | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 715 20 50 1 (d)(ii) | http://www.xbrl.org/2003/role/exampleRef | 715 |
| FASB Accounting Standards Codification 942 210 S99 1 (SX 210.9-03(6)(a)(1)) | http://www.xbrl.org/2003/role/disclosureRef | 942 |
| FASB Accounting Standards Codification 944 80 50 1 (e) | http://www.xbrl.org/2009/role/commonPracticeRef | 944 |