Revenue - Revenues by Geographic Areas (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenues by Geographic Areas [Line Items]
Total revenues	$ 1,267.9	$ 1,121.5	$ 2,453.7	$ 2,169.2
United States
Revenues by Geographic Areas [Line Items]
Total revenues	1,092.6	986.1	2,121.1	1,908.4
Canada
Revenues by Geographic Areas [Line Items]
Total revenues	79.2	63.7	151.8	123.3
Other foreign countries
Revenues by Geographic Areas [Line Items]
Total revenues	$ 96.1	$ 71.7	$ 180.8	$ 137.5