Acquisitions and Divestitures Acquisitions (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended				9 Months Ended		3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Jun. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Dec. 31, 2012 Nexsan Corporation	Sep. 30, 2013 MXI Security	Dec. 31, 2012 MXI Security	Mar. 31, 2013 BeCompliant Corporation (Encryptx)	Dec. 31, 2012 BeCompliant Corporation (Encryptx)	Sep. 30, 2013 Cash Flows from Financing Activities BeCompliant Corporation (Encryptx)	Sep. 30, 2013 Cash Flows from Operating Activities BeCompliant Corporation (Encryptx)
Business Acquisition, Contingent Consideration [Line Items]
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net							$ 120.1
Goodwill	71.7			71.7		73.5	65.5
Goodwill, Purchase Accounting Adjustments			0.6	1.6	0
Contingent consideration obligation								0.2	0.6		0.6
Contingent consideration adjustment	0	(5.5)		(0.4)	(8.3)			0.4
Contingent consideration payments				$ (0.5)	$ (1.2)					$ 0.8		$ 0.5	$ 0.3