v3.8.0.1

Employee Benefit Plans (Asset Allocation Targets Reflecting a Percentage of Total Assets by Asset Class) (Details) | Dec. 31, 2017
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Minimum | Pension Benefits | Equity securities | U.S. |
Defined Benefit Plan Disclosure [Line Items] |
Asset allocation targets | 2.00%
Minimum | Pension Benefits | Equity securities | International |
Defined Benefit Plan Disclosure [Line Items] |
Asset allocation targets | 2.00%
Minimum | Pension Benefits | Fixed Maturities |
Defined Benefit Plan Disclosure [Line Items] |
Asset allocation targets | 48.00%
Minimum | Pension Benefits | Short-term Investments |
Defined Benefit Plan Disclosure [Line Items] |
Asset allocation targets | 0.00%
Minimum | Pension Benefits | Real Estate |
Defined Benefit Plan Disclosure [Line Items] |
Asset allocation targets | 2.00%
Minimum | Pension Benefits | Other |
Defined Benefit Plan Disclosure [Line Items] |
Asset allocation targets | 0.00%
Minimum | Other Postretirement Benefits | Equity securities | U.S. |
Defined Benefit Plan Disclosure [Line Items] |
Asset allocation targets | 29.00%
Minimum | Other Postretirement Benefits | Equity securities | International |
Defined Benefit Plan Disclosure [Line Items] |
Asset allocation targets | 2.00%
Minimum | Other Postretirement Benefits | Fixed Maturities |
Defined Benefit Plan Disclosure [Line Items] |
Asset allocation targets | 4.00%
Minimum | Other Postretirement Benefits | Short-term Investments |
Defined Benefit Plan Disclosure [Line Items] |
Asset allocation targets | 0.00%
Minimum | Other Postretirement Benefits | Real Estate |
Defined Benefit Plan Disclosure [Line Items] |
Asset allocation targets | 0.00%
Minimum | Other Postretirement Benefits | Other |
Defined Benefit Plan Disclosure [Line Items] |
Asset allocation targets | 0.00%
Maximum | Pension Benefits | Equity securities | U.S. |
Defined Benefit Plan Disclosure [Line Items] |
Asset allocation targets | 16.00%
Maximum | Pension Benefits | Equity securities | International |
Defined Benefit Plan Disclosure [Line Items] |
Asset allocation targets | 17.00%
Maximum | Pension Benefits | Fixed Maturities |
Defined Benefit Plan Disclosure [Line Items] |
Asset allocation targets | 67.00%
Maximum | Pension Benefits | Short-term Investments |
Defined Benefit Plan Disclosure [Line Items] |
Asset allocation targets | 15.00%
Maximum | Pension Benefits | Real Estate |
Defined Benefit Plan Disclosure [Line Items] |
Asset allocation targets | 16.00%
Maximum | Pension Benefits | Other |
Defined Benefit Plan Disclosure [Line Items] |
Asset allocation targets | 17.00%
Maximum | Other Postretirement Benefits | Equity securities | U.S. |
Defined Benefit Plan Disclosure [Line Items] |
Asset allocation targets | 66.00%
Maximum | Other Postretirement Benefits | Equity securities | International |
Defined Benefit Plan Disclosure [Line Items] |
Asset allocation targets | 24.00%
Maximum | Other Postretirement Benefits | Fixed Maturities |
Defined Benefit Plan Disclosure [Line Items] |
Asset allocation targets | 51.00%
Maximum | Other Postretirement Benefits | Short-term Investments |
Defined Benefit Plan Disclosure [Line Items] |
Asset allocation targets | 39.00%
Maximum | Other Postretirement Benefits | Real Estate |
Defined Benefit Plan Disclosure [Line Items] |
Asset allocation targets | 0.00%
Maximum | Other Postretirement Benefits | Other |
Defined Benefit Plan Disclosure [Line Items] |
Asset allocation targets | 0.00%

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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Definition Percentage of target investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan. + 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 (d)(5)(i) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 + Details
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