Leases - Supplemental Income Statement Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Operating lease cost:
Operating lease cost	$ 8.6	$ 15.5
Short-term lease cost	9.9	8.3
Variable lease cost	1.0	6.0
Sublease income	0.0	(1.4)
Total operating lease cost	19.5	28.4
Finance lease cost:
Amortization of right-of-use assets	3.4	4.1
Interest on lease liabilities	0.2	0.5
Total finance lease cost	$ 3.6	$ 4.6