Summary of Significant Accounting Policies Property and Equipment (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Property, Plant and Equipment [Line Items]
Depreciation	$ 23.8	$ 23.9	$ 21.9
Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives of the assets	2 years
Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives of the assets	27 years