| Standard label: | Liability for Future Policy Benefit, Activity [Table Text Block] |
| Name: | us-gaap:LiabilityForFuturePolicyBenefitActivityTableTextBlock |
| Documentation: | Tabular disclosure of beginning balance to ending balance for liability for future policy benefit, with separate presentation of expected future net premium and expected future benefit. |
| 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:LiabilityForFuturePolicyBenefitActivityTableTextBlock |
| Label | Role | Language |
| Liability for Future Policy Benefit, Activity [Table Text Block] | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 944 40 55 29E | http://www.xbrl.org/2003/role/exampleRef | 944 |
| FASB Accounting Standards Codification 944 40 65 2 (g)(1) | http://www.xbrl.org/2003/role/disclosureRef | 944 |
| FASB Accounting Standards Codification 944 40 50 6 (a) | http://www.xbrl.org/2003/role/disclosureRef | 944 |