Leases - Schedule of components of leased cost (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Lessor, Lease, Description [Line Items]
Operating lease	$ 35.6	$ 41.4
Short-term lease	8.8	3.8
Variable Lease	7.8	13.1
Operating lease cost	52.2	58.3
Amortization of leased assets	0.7	0.5
Interest on lease liabilities	0.2	0.2
Lease impairment	77.5	0.0
Net lease cost	130.6	59.0
Office space
Lessor, Lease, Description [Line Items]
Operating lease	$ 1.5	$ 1.3