| Standard label: | Additional Liability, Long-Duration Insurance, Activity [Table] |
| Name: | us-gaap:AdditionalLiabilityLongDurationInsuranceActivityTable |
| Documentation: | Disclosure of information about activity in balance of present value of total expected payment to policyholder in excess of present value of total expected assessment. Includes, but is not limited to, beginning and ending balance, issuance, interest income (expense), net premium, benefit payment, derecognition (lapse), experience adjustment, change in cash flow assumption, and change in discount rate assumption. Excludes benefit classified as market risk benefit or under provisions of Topic 815 on derivative and hedging. |
| Object type: | cm:Table |
| Data type: | Text/String (xbrli:stringItemType) |
| Period type: | For Period (duration) |
| Balance type: | (no balance type) |
| Abstract: | true |
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:AdditionalLiabilityLongDurationInsuranceActivityTable |
| Label | Role | Language |
| Additional Liability, Long-Duration Insurance, Activity [Table] | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 944 40 50 6 (a) | http://www.xbrl.org/2003/role/disclosureRef | 944 |