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Pension and Savings Plans (Details 4) - USD ($) $ in Millions | Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014
--- | --- | --- | ---
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value | $ 295.1 | $ 281.2 |
Level 1 [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets at end of period | 162.8 | 152.1 |
Level 2 [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets at end of period | 301.0 | 301.0 |
Level 3 [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets at end of period | 14.1 | 23.0 |
Equity Funds [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets at end of period | 119.9 | 107.1 |
Equity Funds [Member] | Level 1 [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets at end of period | 119.9 | 107.1 |
Equity Funds [Member] | Level 2 [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets at end of period | 0.0 | 0.0 |
Equity Funds [Member] | Level 3 [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets at end of period | 0.0 | 0.0 |
International equity securities | Level 3 [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets at end of period |  | 0.0 |
U.S. debt securities |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets at end of period | 47.8 | 53.4 |
U.S. debt securities | Level 1 [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets at end of period | 25.1 | 26.8 |
U.S. debt securities | Level 2 [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets at end of period | 22.7 | 26.6 |
U.S. debt securities | Level 3 [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets at end of period | 0.0 |  |
International debt securities |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets at end of period | 12.6 | 15.0 |
International debt securities | Level 1 [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets at end of period | 0.0 | 0.0 |
International debt securities | Level 2 [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets at end of period | 12.6 | 15.0 |
International debt securities | Level 3 [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets at end of period | 0.0 | 0.0 |
Banks, Trust and Insurance, Equities [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets at end of period | 109.0 | 97.3 |
Corporate Debt Securities [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets at end of period | 265.7 | 259.4 |
Corporate Debt Securities [Member] | Level 1 [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets at end of period | 0.0 | 0.0 |
Corporate Debt Securities [Member] | Level 2 [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets at end of period | 265.7 | 259.4 |
Corporate Debt Securities [Member] | Level 3 [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets at end of period | 0.0 | 0.0 |
Short-term investments |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets at end of period | 17.8 | 18.2 |
Short-term investments | Level 1 [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets at end of period | 17.8 | 18.2 |
Short-term investments | Level 2 [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets at end of period | 0.0 | 0.0 |
Short-term investments | Level 3 [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets at end of period | 0.0 | 0.0 |
Interests in real estate |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets at end of period | 14.1 | 23.0 |
Interests in real estate | Level 1 [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets at end of period | 0.0 | 0.0 |
Interests in real estate | Level 2 [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets at end of period | 0.0 | 0.0 |
Interests in real estate | Level 3 [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets at end of period | 14.1 | 23.0 | $ 30.2
Private Equity Funds [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets at end of period | 186.1 | 183.9 |
Pension Plans, Defined Benefit [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets at end of period | 773.0 | 757.3 | $ 839.8
Fair Value Pension Plan Assets [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets at end of period | $ 477.9 | $ 476.1 |

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