Goodwill and Intangible Assets (Changes in Carrying Amount of Goodwill) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2018
Goodwill [Line Items]
Goodwill, gross, beginning balance	$ 10,590.7
Accumulated impairment losses, beginning balance	(385.0)
Foreign currency translation	112.6
Goodwill, net, beginning balance	10,205.7
Goodwill, gross, ending balance	10,703.3
Accumulated impairment losses, ending balance	(385.0)
Goodwill, net, ending balance	10,205.7	$ 10,318.3
North America Segment
Goodwill [Line Items]
Goodwill, gross, beginning balance	3,934.6
Accumulated impairment losses, beginning balance	(385.0)
Foreign currency translation	(5.9)
Goodwill, net, beginning balance	3,549.6
Goodwill, gross, ending balance	3,928.7
Accumulated impairment losses, ending balance	(385.0)
Goodwill, net, ending balance	3,549.6	3,543.7
Europe Segment
Goodwill [Line Items]
Goodwill, gross, beginning balance	4,967.1
Accumulated impairment losses, beginning balance	0.0
Foreign currency translation	112.6
Goodwill, net, beginning balance	4,967.1
Goodwill, gross, ending balance	5,079.7
Accumulated impairment losses, ending balance	0.0
Goodwill, net, ending balance	4,967.1	5,079.7
Rest of World Segment
Goodwill [Line Items]
Goodwill, gross, beginning balance	1,689.0
Accumulated impairment losses, beginning balance	0.0
Foreign currency translation	5.9
Goodwill, net, beginning balance	1,689.0
Goodwill, gross, ending balance	1,694.9
Accumulated impairment losses, ending balance	0.0
Goodwill, net, ending balance	$ 1,689.0	$ 1,694.9