Goodwill and Other Intangible Assets, Acquired Intangible Assets (Details) (Acquired Finite-Lived Intangible Assets [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Acquired Finite-Lived Intangible Assets [Member]
Intangible assets, Finite-lived [Abstract]
Amortization expense	$ 4.6	$ 0.6	$ 0.6
Estimated amortization expense, 2015	7.9
Estimated amortization expense, 2016	7.9
Estimated amortization expense, 2017	7.7
Estimated amortization expense, 2018	7.5
Estimated amortization expense, 2019	7.5
Estimated amortization expense, thereafter	$ 173.6