Acquisitions and Divestitures - Discontinued Operations (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Long Lived Assets Held-for-sale [Line Items]
Loss on sale of discontinued businesses, net of income taxes	$ 0	$ (5.5)	$ (1.7)	$ (5.5)
Loss from operations of discontinued businesses, net of income taxes	0	(3.2)	(0.6)	(12.0)
Loss from discontinued operations, net of income taxes	0	(8.7)	(2.3)	(17.5)
XtremeMac and Memorex
Long Lived Assets Held-for-sale [Line Items]
Net revenue	0	10.5	0.5	33.9
Loss on sale of discontinued businesses, net of income taxes	0	(5.5)	(1.7)	(5.5)
Loss from operations of discontinued businesses, net of income taxes	0	(3.2)	(0.6)	(12.0)
Income tax provision (benefit)	0	0	0	0
Loss from discontinued operations, net of income taxes	$ 0	$ (8.7)	$ (2.3)	$ (17.5)