Leases - Lease Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Lease Cost
Operating lease costs	$ 49.5
Short-term lease costs	17.4
Sublease income	(6.4)
Net lease costs	60.5
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows from operating leases	(49.5)
Non-cash lease liability arising from obtaining right of use assets during the period	$ 15.9	$ 0.0	$ 0.0
Weighted-average remaining lease term (years) operating leases	6 years 8 months 12 days
Weighted-average discount rate operating leases (2)	6.00%