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)