Long-term Debt - Interest Expense, Net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Debt Disclosure [Abstract]
Interest expense	$ (546.3)	$ (535.9)	$ (539.4)
Interest income	0.9	1.4	1.0
Capitalized interest	2.2	0.3	0.0
Interest expense, net	(543.2)	$ (534.2)	$ (538.4)
Coupon interest	5.7
Amortization of debt discount	7.3
Amortization of debt issuance costs	0.5
Convertible Notes interest expense	$ 13.5