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Postretirement and Other Benefits - Narrative (Details) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined contribution cost recognized | $ 4.0 | $ 3.9 | $ 3.6
Liability under deferred compensation plans | 14.5 | 19.7 |
Grantor trust assets | 18.0 | 14.7 |
Other liabilities, French law CET account | $ 7.0 | $ 6.3 |
United States | Unfunded Plan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Coverage age | 65 years |  |

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