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Pension Plans and Postretirement Benefits - Additional Details (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2020 | Sep. 30, 2019 | Sep. 30, 2020 | Sep. 30, 2019
Retirement Benefits [Abstract] |  |  |  |
Service cost | $ 2.5 | $ 2.1 | $ 8.5 | $ 7.3
Net periodic benefit (income) cost, excluding service costs | $ (9.5) | $ (5.3) | $ (28.5) | $ (15.8)

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