Intangible Assets - Accumulated Impairment, Changes in Goodwill and Other Indefinite-Lived Intangibles (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2012
Intangible Assets
Goodwill, Accumulated impairment loss				$ 606.3
Other indefinite-lived intangible assets, Accumulated impairment loss				$ 37.1
Summary of the changes in the carrying amount of goodwill and other indefinite-lived intangible assets
Goodwill, Beginning balance	$ 1,660.5	$ 1,291.2
Goodwill, Additions	144.1	324.8
Goodwill, Disposals	(13.8)	(4.5)
Goodwill, Foreign currency translation	(38.8)	49.0
Goodwill, Ending balance	1,752.0	1,660.5	$ 1,291.2
Other indefinite-lived intangible assets, Beginning Balance	474.0	420.1
Other indefinite-lived intangible assets, Additions	29.8	40.8
Other indefinite-lived intangible assets, Disposals	(0.5)	(1.7)
Other indefinite-lived intangible assets, Impairment	(5.8)	0.0	0.0
Other indefinite-lived intangible assets, Foreign currency translation	(11.3)	14.8
Other indefinite-lived intangible assets, Ending Balance	$ 486.2	$ 474.0	$ 420.1