Commitments and Contingencies - Lease Commitments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Lease Commitments
Minimum term of non-cancelable lease commitments for further disclosure	1 year
Rental expense	$ 82.7	$ 77.9	$ 78.9
Operating lease payments due to various related parties	4.1	$ 3.4	$ 3.6
Operating Leases
2019	59.5
2020	45.5
2021	32.9
2022	22.7
2023	16.2
Thereafter	40.7
Total	$ 217.5