Redeemable Noncontrolling Interests (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Redeemable Noncontrolling Interests [Abstract]
Purchase of noncontrolling interests		$ 44.1
Other comprehensive income (loss)	$ 32.8
Redemption value adjustment	32.0
Redemption of shares	(3.5)
Reclassification of noncontrolling interest	386.7	407.9
Redeemable noncontrolling interests	$ 492.1	$ 44.1	$ 0.0