Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Change in the carrying amount of goodwill
Balance at the beginning of the period	$ 1,724.8	$ 1,736.4	$ 1,691.6
Acquisitions	103.4	0.4	51.3
Consolidation of a joint venture entity			15.2
Purchase price allocation adjustments		(0.4)	2.1
Sale of business			(17.1)
Disposal of businesses	(1.0)
Effect of foreign currency translation	0.2	(11.6)	(6.7)
Balance at the end of the period	1,827.4	$ 1,724.8	$ 1,736.4
Accumulated impairment losses	0.0
Goodwill, tax deductible amount	662.5
2016 Acquisitions
Change in the carrying amount of goodwill
Balance at the end of the period	103.4
Goodwill, tax deductible amount	$ 103.4