Summary of Significant Accounting Policies Property, plant and equipment (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Property, Plant and Equipment [Line Items]
Capitalized Interest Costs	$ 3.4	$ 3.0	$ 3.1
Building [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Buildings	10 years
Building [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Buildings	30 years
Leasehold Improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Buildings	3 years
Leasehold Improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Buildings	10 years
Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Buildings	3 years
Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Buildings	7 years
Furniture and Fixtures [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Buildings	3 years
Furniture and Fixtures [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Buildings	7 years