| Standard label: | Other than Temporary Impairment, Credit Losses Recognized in Earnings, Period Increase (Decrease) |
| Name: | us-gaap:OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsPeriodIncreaseDecrease |
| Documentation: | Amount of increase (decrease) in the cumulative amount of credit losses recognized in earnings related to debt securities held for which a portion of an other than temporary impairment (OTTI) was recognized in other comprehensive income (loss). |
| 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:OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsPeriodIncreaseDecrease |
| Label | Role | Language |
| Other than Temporary Impairment, Credit Losses Recognized in Earnings, Period Increase (Decrease) | http://www.xbrl.org/2003/role/label | en-US |
| Other than Temporary Impairment, Credit Losses Recognized in Earnings, Period Increase (Decrease), Total | http://www.xbrl.org/2003/role/totalLabel | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 320 10 50 8B | http://fasb.org/us-gaap/role/ref/legacyRef | 320 |