| Standard label: | Closed Block Assets and Liabilities Maximum Future Earnings to be Recognized, Period Increase (Decrease) |
| Name: | us-gaap:ClosedBlockAssetsAndLiabilitiesMaximumFutureEarningsToBeRecognizedPeriodIncreaseDecrease |
| Documentation: | Amount of increase (decrease) of closed block liabilities in excess of closed block assets at the date of demutualization. |
| Object type: | cm:Concept |
| Data type: | Monetary (xbrli:monetaryItemType) |
| Period type: | For Period (duration) |
| Balance type: | (no balance type) |
| Abstract: | false |
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:ClosedBlockAssetsAndLiabilitiesMaximumFutureEarningsToBeRecognizedPeriodIncreaseDecrease |
| Label | Role | Language |
| Closed Block Assets and Liabilities Maximum Future Earnings to be Recognized, Period Increase (Decrease) | http://www.xbrl.org/2003/role/label | en-US |
| Closed Block Assets and Liabilities Maximum Future Earnings to be Recognized, Period Increase (Decrease), Total | http://www.xbrl.org/2003/role/totalLabel | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 944 805 50 3 (b)(9) | http://fasb.org/us-gaap/role/ref/legacyRef | 944 |
| FASB Accounting Standards Codification 944 805 55 4 | http://fasb.org/us-gaap/role/ref/legacyRef | 944 |