Goodwill and Other Intangible Assets - Goodwill Rollforward (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014	Dec. 31, 2013
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 189.3	$ 23.8	$ 189.3	$ 23.8	$ 169.2	$ 168.9	$ 23.8	$ 0.0
Intangible Assets, Net (Excluding Goodwill)	192.4	42.0	192.4	42.0	$ 171.2	$ 182.3	$ 44.6	$ 5.1
Goodwill, Acquired During Period	20.1	0.0	20.4	23.8
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	28.1	0.0	30.9	42.4
Disposition of Goodwill through disposition of business	0.0	0.0	0.0	0.0
Amortization of Intangible Assets	$ (6.9)	$ (2.6)	$ (20.8)	$ (5.5)