Fair Value Measurement (Assets and Liabilities Measure at Fair Value on Recurring Basis using Level 3 Inputs) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at January 1,	$ 15.6	$ 13.8
Change in fair value included in earnings	(2.5)	3.6
Other	(4.8)	(1.7)
Balance as of September 30,	8.3	15.7
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at January 1,	1,058.0	475.9
Acquisitions	(4.0)	557.0
Change in fair value included in earnings	144.3	(34.8)
Other	(11.4)	(1.4)
Balance as of September 30,	$ 1,186.9	$ 996.7