Segment Reporting (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenue and Long-Lived Assets and Goodwill by Geographic Region
Revenue	$ 3,468.9	$ 3,629.6
Americas
Revenue and Long-Lived Assets and Goodwill by Geographic Region
Revenue	2,078.2	2,094.1
Long-lived assets and goodwill	7,703.9	6,838.3
United States
Revenue and Long-Lived Assets and Goodwill by Geographic Region
Revenue	1,884.1	1,881.0
EMEA
Revenue and Long-Lived Assets and Goodwill by Geographic Region
Revenue	1,024.5	1,143.5
Long-lived assets and goodwill	3,004.3	2,941.3
Asia-Pacific
Revenue and Long-Lived Assets and Goodwill by Geographic Region
Revenue	366.2	392.0
Long-lived assets and goodwill	$ 655.8	$ 547.5