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Employee Benefit Plans (Fair Value Measurement of Plan Assets) (Details) - USD ($) $ in Millions | Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014
--- | --- | --- | ---
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | $ 159.7 | $ 147.2 | $ 145.7
Cash/Money Markets [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 4.9 | 4.6 |
Foreign Government/Treasury Securities [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 15.6 | 9.0 |
Corporate Bonds, Debentures [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 32.0 | 30.3 |
Equity Securities [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 28.8 | 26.7 |
Mutual Funds [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 8.8 | 7.7 |
Investment and Insurance Annuity Contracts [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 69.6 | 68.9 |
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 20.5 | 12.9 |
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Cash/Money Markets [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 4.9 | 4.6 |
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Foreign Government/Treasury Securities [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 15.6 | 8.3 |
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Corporate Bonds, Debentures [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0.0 | 0.0 |
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Equity Securities [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0.0 | 0.0 |
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Mutual Funds [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0.0 | 0.0 |
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Investment and Insurance Annuity Contracts [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0.0 | 0.0 |
Significant Observable Inputs (Level 2) [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 92.0 | 86.7 |
Significant Observable Inputs (Level 2) [Member] | Cash/Money Markets [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0.0 | 0.0 |
Significant Observable Inputs (Level 2) [Member] | Foreign Government/Treasury Securities [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0.0 | 0.7 |
Significant Observable Inputs (Level 2) [Member] | Corporate Bonds, Debentures [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 32.0 | 29.7 |
Significant Observable Inputs (Level 2) [Member] | Equity Securities [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 28.8 | 26.7 |
Significant Observable Inputs (Level 2) [Member] | Mutual Funds [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 8.8 | 7.7 |
Significant Observable Inputs (Level 2) [Member] | Investment and Insurance Annuity Contracts [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 22.4 | 21.9 |
Significant Unobservable Inputs (Level 3) [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 47.2 | 47.6 | 52.2
Significant Unobservable Inputs (Level 3) [Member] | Cash/Money Markets [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0.0 | 0.0 |
Significant Unobservable Inputs (Level 3) [Member] | Foreign Government/Treasury Securities [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0.0 | 0.0 |
Significant Unobservable Inputs (Level 3) [Member] | Corporate Bonds, Debentures [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0.0 | 0.6 | 0.7
Significant Unobservable Inputs (Level 3) [Member] | Equity Securities [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0.0 | 0.0 |
Significant Unobservable Inputs (Level 3) [Member] | Mutual Funds [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 0.0 | 0.0 |
Significant Unobservable Inputs (Level 3) [Member] | Investment and Insurance Annuity Contracts [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | $ 47.2 | $ 47.0 | $ 51.5

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