| Standard label: | Additional Liability, Long-Duration Insurance [Policy Text Block] |
| Name: | us-gaap:AdditionalLiabilityLongDurationInsurancePolicyTextBlock |
| Documentation: | Disclosure of accounting policy for present value of total expected payment to policyholder in excess of present value of total expected assessment. Includes, but is not limited to, input, judgment, assumption and method used in measuring liability, and change in input, judgment, and assumption. Excludes benefit classified as market risk benefit or under provisions of Topic 815 on derivative and hedging. |
| Object type: | cm:Level2TextBlock |
| 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:AdditionalLiabilityLongDurationInsurancePolicyTextBlock |
| Label | Role | Language |
| Additional Liability, Long-Duration Insurance [Policy Text Block] | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 944 40 50 6 (b)(6) | http://www.xbrl.org/2003/role/disclosureRef | 944 |
| FASB Accounting Standards Codification 944 40 50 7 | http://www.xbrl.org/2003/role/disclosureRef | 944 |