Segment Reporting (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenue and Long-Lived Assets and Goodwill by Geographic Region
Revenue	$ 3,623.8	$ 3,714.3	$ 10,812.5	$ 11,203.5
Americas
Revenue and Long-Lived Assets and Goodwill by Geographic Region
Revenue	2,196.7	2,197.5	6,490.1	6,504.2
Long-lived assets and goodwill	7,844.6	6,930.2	7,844.6	6,930.2
EMEA
Revenue and Long-Lived Assets and Goodwill by Geographic Region
Revenue	1,008.2	1,078.9	3,129.6	3,435.1
Long-lived assets and goodwill	2,862.9	2,611.1	2,862.9	2,611.1
Asia-Pacific
Revenue and Long-Lived Assets and Goodwill by Geographic Region
Revenue	418.9	437.9	1,192.8	1,264.2
Long-lived assets and goodwill	$ 632.0	$ 552.1	$ 632.0	$ 552.1