Redeemable Noncontrolling Interests - Table 2 (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Noncontrolling Interest [Abstract]
Net income attributable to nonredeemable noncontrolling interests	$ 15.0	$ 12.7	$ 43.3	$ 42.5
Net income attributable to redeemable noncontrolling interests	4.2	3.7	9.9	11.2
Net income attributable to noncontrolling interests	$ 19.2	$ 16.4	$ 53.2	$ 53.7