| Standard label: | Closed Block Assets and Liabilities, Maximum Future Earnings to be Recognized |
| Name: | us-gaap:ClosedBlockAssetsAndLiabilitiesMaximumFutureEarningsToBeRecognized |
| Documentation: | The carrying amount of closed block liabilities in excess of the carrying amount of closed block assets at the date of demutualization (adjusted to eliminate the impact of related amounts in accumulated other comprehensive income). |
| Object type: | cm:Concept |
| Data type: | Monetary (xbrli:monetaryItemType) |
| Period type: | As Of (instant) |
| Balance type: | Credit |
| Abstract: | false |
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:ClosedBlockAssetsAndLiabilitiesMaximumFutureEarningsToBeRecognized |
| Label | Role | Language |
| Closed Block Assets and Liabilities, Maximum Future Earnings to be Recognized | http://www.xbrl.org/2003/role/label | en-US |
| Closed Block Assets and Liabilities, Maximum Future Earnings to be Recognized, Ending Balance | http://www.xbrl.org/2003/role/periodEndLabel | en-US |
| Closed Block Assets and Liabilities, Maximum Future Earnings to be Recognized, Beginning Balance | http://www.xbrl.org/2003/role/periodStartLabel | en-US |
| Closed Block Assets and Liabilities, Maximum Future Earnings to be Recognized, 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 |