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Postretirement and Other Benefits - Narrative (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined contribution cost recognized | $ 3.6 | $ 3.6 | $ 2.5
Liability under deferred compensation plans | 14.1 | 17.4 |
Grantor trust assets | 10.9 | 12.2 |
Other liabilities, French law CET account | $ 5.5 | $ 5.6 |
United States | Unfunded Plan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Coverage age | 65 years |  |

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