| **Benefit Plans (Fair Value of Plan Assets Measured on a Recurring Basis) (Details) (USD $)In Millions, unless otherwise specified** | 12 Months Ended                                                                                                                                                                                                                                                |                                                                                                                                                                                                                                                                |                                                                                                                                                                                                                                                      |
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| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Document Period End Date                                                                                                             | Dec. 31,  2014                                                                                                                                                                                                                                                 |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Corporate and other bonds [Member]                                                                                                   |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 478us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CorporateDebtSecuritiesMember                                                                                                                 | $ 520us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CorporateDebtSecuritiesMember                                                                                                               |                                                                                                                                                                                                                                                 |
| Corporate and other bonds [Member] | Fair Value, Inputs, Level 1 [Member]                                                            |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CorporateDebtSecuritiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                              | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CorporateDebtSecuritiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                              |                                                                                                                                                                                                                                                 |
| Corporate and other bonds [Member] | Fair Value, Inputs, Level 2 [Member]                                                            |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 463us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CorporateDebtSecuritiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                            | 505us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CorporateDebtSecuritiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                            |                                                                                                                                                                                                                                                 |
| Corporate and other bonds [Member] | Fair Value, Inputs, Level 3 [Member]                                                            |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 15us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CorporateDebtSecuritiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                             | 15us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CorporateDebtSecuritiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                             | 11us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CorporateDebtSecuritiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                   |
| States, municipalities and political subdivisions [Member]                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 80us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_USStatesAndPoliticalSubdivisionsMember                                                                                                         | 73us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_USStatesAndPoliticalSubdivisionsMember                                                                                                         |                                                                                                                                                                                                                                                 |
| States, municipalities and political subdivisions [Member] | Fair Value, Inputs, Level 1 [Member]                                    |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_USStatesAndPoliticalSubdivisionsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                     | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_USStatesAndPoliticalSubdivisionsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                     |                                                                                                                                                                                                                                                 |
| States, municipalities and political subdivisions [Member] | Fair Value, Inputs, Level 2 [Member]                                    |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 80us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_USStatesAndPoliticalSubdivisionsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                    | 73us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_USStatesAndPoliticalSubdivisionsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                    |                                                                                                                                                                                                                                                 |
| States, municipalities and political subdivisions [Member] | Fair Value, Inputs, Level 3 [Member]                                    |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_USStatesAndPoliticalSubdivisionsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                     | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_USStatesAndPoliticalSubdivisionsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                     |                                                                                                                                                                                                                                                 |
| Residential mortgage-backed [Member]                                                                                                 |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 123us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_ResidentialMortgageBackedSecuritiesMember                                                                                                     | 130us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_ResidentialMortgageBackedSecuritiesMember                                                                                                     |                                                                                                                                                                                                                                                 |
| Residential mortgage-backed [Member] | Fair Value, Inputs, Level 1 [Member]                                                          |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_ResidentialMortgageBackedSecuritiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                  | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_ResidentialMortgageBackedSecuritiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                  |                                                                                                                                                                                                                                                 |
| Residential mortgage-backed [Member] | Fair Value, Inputs, Level 2 [Member]                                                          |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 123us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_ResidentialMortgageBackedSecuritiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                | 130us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_ResidentialMortgageBackedSecuritiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                |                                                                                                                                                                                                                                                 |
| Residential mortgage-backed [Member] | Fair Value, Inputs, Level 3 [Member]                                                          |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_ResidentialMortgageBackedSecuritiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                  | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_ResidentialMortgageBackedSecuritiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                  |                                                                                                                                                                                                                                                 |
| Commercial Mortgage Backed Securities [Member]                                                                                       |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 75us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CommercialMortgageBackedSecuritiesMember                                                                                                       | 106us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CommercialMortgageBackedSecuritiesMember                                                                                                      |                                                                                                                                                                                                                                                 |
| Commercial Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 1 [Member]                                                |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CommercialMortgageBackedSecuritiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                   | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CommercialMortgageBackedSecuritiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                   |                                                                                                                                                                                                                                                 |
| Commercial Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]                                                |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 75us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CommercialMortgageBackedSecuritiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                  | 106us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CommercialMortgageBackedSecuritiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                 |                                                                                                                                                                                                                                                 |
| Commercial Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]                                                |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CommercialMortgageBackedSecuritiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                   | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CommercialMortgageBackedSecuritiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                   |                                                                                                                                                                                                                                                 |
| Other asset-backed [Member]                                                                                                          |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 12us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember                                                                                      | 12us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember                                                                                      |                                                                                                                                                                                                                                                 |
| Other asset-backed [Member] | Fair Value, Inputs, Level 1 [Member]                                                                   |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member  | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member  |                                                                                                                                                                                                                                                 |
| Other asset-backed [Member] | Fair Value, Inputs, Level 2 [Member]                                                                   |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 12us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member | 12us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member |                                                                                                                                                                                                                                                 |
| Other asset-backed [Member] | Fair Value, Inputs, Level 3 [Member]                                                                   |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member  | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member  |                                                                                                                                                                                                                                                 |
| Total asset-backed [Member]                                                                                                          |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 210us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_AssetBackedSecuritiesMember                                                                                                                   | 248us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_AssetBackedSecuritiesMember                                                                                                                   |                                                                                                                                                                                                                                                 |
| Total asset-backed [Member] | Fair Value, Inputs, Level 1 [Member]                                                                   |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_AssetBackedSecuritiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                                | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_AssetBackedSecuritiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                                |                                                                                                                                                                                                                                                 |
| Total asset-backed [Member] | Fair Value, Inputs, Level 2 [Member]                                                                   |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 210us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_AssetBackedSecuritiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                              | 248us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_AssetBackedSecuritiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                              |                                                                                                                                                                                                                                                 |
| Total asset-backed [Member] | Fair Value, Inputs, Level 3 [Member]                                                                   |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_AssetBackedSecuritiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                                | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_AssetBackedSecuritiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                                |                                                                                                                                                                                                                                                 |
| U.S. Treasury and obligations of government-sponsored enterprises [Member]                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 25us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_USTreasuryAndGovernmentMember                                                                                                                  |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| U.S. Treasury and obligations of government-sponsored enterprises [Member] | Fair Value, Inputs, Level 1 [Member]                    |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 25us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_USTreasuryAndGovernmentMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                             |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| U.S. Treasury and obligations of government-sponsored enterprises [Member] | Fair Value, Inputs, Level 2 [Member]                    |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_USTreasuryAndGovernmentMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                              |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| U.S. Treasury and obligations of government-sponsored enterprises [Member] | Fair Value, Inputs, Level 3 [Member]                    |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_USTreasuryAndGovernmentMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                              |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fixed Maturities [Member]                                                                                                            |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 793us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_FixedMaturitiesMember                                                                                                                         | 841us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_FixedMaturitiesMember                                                                                                                         |                                                                                                                                                                                                                                                 |
| Fixed Maturities [Member] | Fair Value, Inputs, Level 1 [Member]                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 25us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_FixedMaturitiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                                     | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_FixedMaturitiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                                      |                                                                                                                                                                                                                                                 |
| Fixed Maturities [Member] | Fair Value, Inputs, Level 2 [Member]                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 753us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_FixedMaturitiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                                    | 826us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_FixedMaturitiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                                    |                                                                                                                                                                                                                                                 |
| Fixed Maturities [Member] | Fair Value, Inputs, Level 3 [Member]                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 15us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_FixedMaturitiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                                     | 15us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_FixedMaturitiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                                     | 11us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_FixedMaturitiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                           |
| Equity securities [Member]                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 507us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_EquitySecuritiesMember                                                                                                                        | 605us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_EquitySecuritiesMember                                                                                                                        |                                                                                                                                                                                                                                                 |
| Equity securities [Member] | Fair Value, Inputs, Level 1 [Member]                                                                    |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 389us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_EquitySecuritiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                                   | 480us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_EquitySecuritiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                                   |                                                                                                                                                                                                                                                 |
| Equity securities [Member] | Fair Value, Inputs, Level 2 [Member]                                                                    |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 118us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_EquitySecuritiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                                   | 117us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_EquitySecuritiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                                   |                                                                                                                                                                                                                                                 |
| Equity securities [Member] | Fair Value, Inputs, Level 3 [Member]                                                                    |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_EquitySecuritiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                                     | 8us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_EquitySecuritiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                                     | 5us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_EquitySecuritiesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                           |
| Derivative Financial Instruments, Assets [Member]                                                                                    |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 1us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_DerivativeFinancialInstrumentsAssetsMember                                                                                                      | 2us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_DerivativeFinancialInstrumentsAssetsMember                                                                                                      |                                                                                                                                                                                                                                                 |
| Derivative Financial Instruments, Assets [Member] | Fair Value, Inputs, Level 1 [Member]                                             |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 1us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_DerivativeFinancialInstrumentsAssetsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                 | 2us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_DerivativeFinancialInstrumentsAssetsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                 |                                                                                                                                                                                                                                                 |
| Derivative Financial Instruments, Assets [Member] | Fair Value, Inputs, Level 2 [Member]                                             |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_DerivativeFinancialInstrumentsAssetsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                 | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_DerivativeFinancialInstrumentsAssetsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                 |                                                                                                                                                                                                                                                 |
| Derivative Financial Instruments, Assets [Member] | Fair Value, Inputs, Level 3 [Member]                                             |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_DerivativeFinancialInstrumentsAssetsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                 | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_DerivativeFinancialInstrumentsAssetsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                 |                                                                                                                                                                                                                                                 |
| Short-term Investments [Member]                                                                                                      |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 134us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_ShortTermInvestmentsMember                                                                                                                    | 94us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_ShortTermInvestmentsMember                                                                                                                     |                                                                                                                                                                                                                                                 |
| Short-term Investments [Member] | Fair Value, Inputs, Level 1 [Member]                                                               |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 33us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_ShortTermInvestmentsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                                | 45us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_ShortTermInvestmentsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                                |                                                                                                                                                                                                                                                 |
| Short-term Investments [Member] | Fair Value, Inputs, Level 2 [Member]                                                               |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 101us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_ShortTermInvestmentsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                               | 49us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_ShortTermInvestmentsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                                |                                                                                                                                                                                                                                                 |
| Short-term Investments [Member] | Fair Value, Inputs, Level 3 [Member]                                                               |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_ShortTermInvestmentsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                                 | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_ShortTermInvestmentsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                                 |                                                                                                                                                                                                                                                 |
| Hedge Funds [Member]                                                                                                                 |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 865us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_HedgeFundsMember                                                                                                                              | 969us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_HedgeFundsMember                                                                                                                              |                                                                                                                                                                                                                                                 |
| Hedge Funds [Member] | Fair Value, Inputs, Level 1 [Member]                                                                          |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_HedgeFundsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                                           | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_HedgeFundsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                                           |                                                                                                                                                                                                                                                 |
| Hedge Funds [Member] | Fair Value, Inputs, Level 2 [Member]                                                                          |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 562us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_HedgeFundsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                                         | 647us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_HedgeFundsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                                         |                                                                                                                                                                                                                                                 |
| Hedge Funds [Member] | Fair Value, Inputs, Level 3 [Member]                                                                          |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 303us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_HedgeFundsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                                         | 322us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_HedgeFundsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                                         | 359us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_HedgeFundsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                               |
| Private Equity Funds [Member]                                                                                                        |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 113us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_PrivateEquityFundsMember                                                                                                                      | 114us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_PrivateEquityFundsMember                                                                                                                      |                                                                                                                                                                                                                                                 |
| Private Equity Funds [Member] | Fair Value, Inputs, Level 1 [Member]                                                                 |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_PrivateEquityFundsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                                   | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_PrivateEquityFundsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                                   |                                                                                                                                                                                                                                                 |
| Private Equity Funds [Member] | Fair Value, Inputs, Level 2 [Member]                                                                 |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_PrivateEquityFundsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                                   | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_PrivateEquityFundsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                                   |                                                                                                                                                                                                                                                 |
| Private Equity Funds [Member] | Fair Value, Inputs, Level 3 [Member]                                                                 |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 113us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_PrivateEquityFundsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                                 | 114us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_PrivateEquityFundsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                                 | 62us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_PrivateEquityFundsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                        |
| Total limited partnerships [Member]                                                                                                  |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 978us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_PartnershipInterestMember                                                                                                                     | 1,083us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_PartnershipInterestMember                                                                                                                   |                                                                                                                                                                                                                                                 |
| Total limited partnerships [Member] | Fair Value, Inputs, Level 1 [Member]                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_PartnershipInterestMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                                  | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_PartnershipInterestMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                                  |                                                                                                                                                                                                                                                 |
| Total limited partnerships [Member] | Fair Value, Inputs, Level 2 [Member]                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 562us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_PartnershipInterestMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                                | 647us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_PartnershipInterestMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                                |                                                                                                                                                                                                                                                 |
| Total limited partnerships [Member] | Fair Value, Inputs, Level 3 [Member]                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 416us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_PartnershipInterestMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                                | 436us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_PartnershipInterestMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                                | 421us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_PartnershipInterestMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                      |
| Other assets [Member]                                                                                                                |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 30us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_OtherAssetsMember                                                                                                                              | 31us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_OtherAssetsMember                                                                                                                              |                                                                                                                                                                                                                                                 |
| Other assets [Member] | Fair Value, Inputs, Level 1 [Member]                                                                         |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_OtherAssetsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                                          | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_OtherAssetsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                                          |                                                                                                                                                                                                                                                 |
| Other assets [Member] | Fair Value, Inputs, Level 2 [Member]                                                                         |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 30us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_OtherAssetsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                                         | 31us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_OtherAssetsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                                         |                                                                                                                                                                                                                                                 |
| Other assets [Member] | Fair Value, Inputs, Level 3 [Member]                                                                         |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_OtherAssetsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                                          | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_OtherAssetsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                                          |                                                                                                                                                                                                                                                 |
| Cash [Member]                                                                                                                        |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 13us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CashMember                                                                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Cash [Member] | Fair Value, Inputs, Level 1 [Member]                                                                                 |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 13us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CashMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                                                |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Cash [Member] | Fair Value, Inputs, Level 2 [Member]                                                                                 |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CashMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                                                 |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Cash [Member] | Fair Value, Inputs, Level 3 [Member]                                                                                 |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CashMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                                                 |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Total assets [Member]                                                                                                                |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 2,456us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember                                                                                                | 2,656us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember                                                                                                |                                                                                                                                                                                                                                                 |
| Total assets [Member] | Fair Value, Inputs, Level 1 [Member]                                                                         |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 461us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member             | 527us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member             |                                                                                                                                                                                                                                                 |
| Total assets [Member] | Fair Value, Inputs, Level 2 [Member]                                                                         |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 1,564us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member           | 1,670us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member           |                                                                                                                                                                                                                                                 |
| Total assets [Member] | Fair Value, Inputs, Level 3 [Member]                                                                         |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                     |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                 |
| Fair value of plan assets                                                                                                            | 431us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member             | $ 459us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member           | $ 447us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The end date of the period reflected on the cover page if a periodic report. For all other reports and registration statements containing historical data, it is the date up through which that historical data is presented.  If there is no historical data in the report, use the filing date. The format of the date is CCYY-MM-DD.
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Assets, usually stocks, bonds, and other investments, that have been segregated and restricted (usually in a trust) to provide benefits, at their fair value as of the measurement date. Plan assets include amounts contributed by the employer (and by employees for a contributory plan) and amounts earned from investing the contributions, less benefits paid. If a plan has liabilities other than for benefits, those non-benefit obligations may be considered as reductions of plan assets.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 30 -Section 35 -Paragraph 50 -URI http://asc.fasb.org/extlink&oid=29635418&loc=d3e12355-114930
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