Restructuring Costs - Summary of Changes in Restructuring Reserve (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	$ 22.2	$ 25.8	$ 28.3
Paid/ Utilized	(26.8)	(24.3)	(48.7)
Expense	73.9	20.7	46.2
Restructuring reserve, ending balance	69.3	22.2	25.8
Severance and benefits
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	21.6	24.6	20.1
Paid/ Utilized	(23.2)	(21.6)	(28.7)
Expense	70.5	18.6	33.2
Restructuring reserve, ending balance	68.9	21.6	24.6
Plant closing and other
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	0.6	1.2	8.2
Paid/ Utilized	(3.6)	(2.7)	(20.0)
Expense	3.4	2.1	13.0
Restructuring reserve, ending balance	$ 0.4	$ 0.6	$ 1.2