Summary of Significant Accounting Policies Translation of Foreign Currencies (Details) (Other Income, USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Other Income
Trading Activity, Gains and Losses, Net [Line Items]
Foreign currency transaction (loss) gain, before tax	$ (24.2)	$ 7.6	$ 4.9