Other Gains and Losses, Net (Schedule of other gains and losses, net) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
OTHER GAINS AND LOSSES, NET
Gain on sale of investments	$ 1.5	$ 3.8	$ 13.0
Net Realized and Unrealized Gain on Trading Securities	14.2	0.0	15.4
Unrealized Gain on Foreign Currency Derivatives, before Tax	22.0	0.0	0.0
Gain on contingent consideration liability	0.0	27.1	0.0
Other realized gains	1.4	0.9	0.2
Total other gains	39.1	31.8	28.6
Other-than-temporary impairment of available-for-sale investments	0.0	(2.0)	0.0
Net Realized and Unrealized Loss on Trading Securities	0.0	(13.5)	0.0
Loss Contingency Accrual	(7.4)	0.0	0.0
Net foreign exchange losses	(6.0)	(2.4)	(0.2)
Foreign exchange hedge loss	0.0	(7.7)	0.0
Realized loss on sale of partnerships	0.0	(7.3)	0.0
Other realized losses	(2.8)	(0.4)	(0.3)
Total other losses	(16.2)	(33.3)	(0.5)
Other gains and losses, net	$ 22.9	$ (1.5)	$ 28.1