Restructuring - Restructuring Reserve Activity (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Restructuring accrual balances and related activity
Balance at beginning of period	$ 42.6	$ 56.9	$ 54.0
Liabilities incurred	81.6	50.2	65.0
Liabilities paid/settled	(61.3)	(64.5)	(62.1)
Balance at end of period	$ 62.9	$ 42.6	$ 56.9