| Standard label: | Market Risk Benefit [Policy Text Block] |
| Name: | us-gaap:MarketRiskBenefitPolicyTextBlock |
| Documentation: | Disclosure of accounting policy for contract or contract feature in long-duration contract issued by insurance entity that both protects contract holder from other-than-nominal capital market risk and exposes insurance entity to other-than-nominal capital market risk. Includes, but is not limited to, input, judgment, assumption and method used in measuring market risk benefit, and change in input, judgment, and assumption. |
| 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:MarketRiskBenefitPolicyTextBlock |
| Label | Role | Language |
| Market Risk Benefit [Policy Text Block] | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 944 40 50 7C | http://www.xbrl.org/2003/role/disclosureRef | 944 |