Restructuring Costs - Summary of Changes in Restructuring Reserve (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance			$ 69.3	$ 22.2
Expense	$ (3.8)	$ 71.7	(0.7)	73.0
Paid/Utilized			(24.9)	(17.9)
Restructuring reserve, ending balance	43.7	77.3	43.7	77.3
Severance and benefits
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance			68.9	21.6
Expense			(4.8)	70.7
Paid/Utilized			(21.0)	(15.6)
Restructuring reserve, ending balance	43.1	76.7	43.1	76.7
Plant closing and other
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance			0.4	0.6
Expense			4.1	2.3
Paid/Utilized			(3.9)	(2.3)
Restructuring reserve, ending balance	$ 0.6	$ 0.6	$ 0.6	$ 0.6