| Standard label: | Other than Temporary Impairment Losses, Investments, Held-to-maturity Securities, Portion Recognized in Earnings, Net, Qualitative Disclosures, Loan to Collateral Value |
| Name: | us-gaap:OtherThanTemporaryImpairmentLossesInvestmentsHeldtomaturitySecuritiesPortionRecognizedInEarningsNetQualitativeDisclosuresLoanToCollateralValue |
| Documentation: | This item represents the loan to collateral ratio of the underlying assets in the security, represented as a percentage, which was considered as one of the potential factors in reaching a conclusion that the held-to-maturity investments are other than temporarily impaired and only the amount of impairment related to credit loss was recognized in earnings. |
| Object type: | cm:Concept |
| Data type: | Percent (num:percentItemType) |
| Period type: | For Period (duration) |
| Balance type: | (no balance type) |
| Abstract: | false |
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:OtherThanTemporaryImpairmentLossesInvestmentsHeldtomaturitySecuritiesPortionRecognizedInEarningsNetQualitativeDisclosuresLoanToCollateralValue |
| Label | Role | Language |
| Other than Temporary Impairment Losses, Investments, Held-to-maturity Securities, Portion Recognized in Earnings, Net, Qualitative Disclosures, Loan to Collateral Value | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 320 10 50 8A b. | http://fasb.org/us-gaap/role/ref/legacyRef | 320 |