Long-term Debt - Interest Expense, Net (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Debt Disclosure [Abstract]
Interest expense	$ (146.1)	$ (143.3)	$ (421.8)	$ (409.4)
Interest income	0.3	0.3	0.7	0.7
Capitalized interest	0.9	0.7	2.5	1.6
Interest expense, net	(144.9)	(142.3)	(418.6)	(407.1)
Coupon interest	2.3	2.3	6.8	3.5
Amortization of debt discount	3.2	2.9	9.4	4.3
Amortization of debt issuance costs	0.2	0.2	0.7	0.3
Convertible Notes interest expense	$ 5.7	$ 5.4	$ 16.9	$ 8.1