Goodwill and Purchased Intangible Assets, Finite Lived Intangible Assets by Class (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Purchased Intangible Assets [Line Items]
Net	$ 33.9
Total purchased intangible assets, gross	646.9	$ 646.9
Total purchased intangible assets, accumulated amortization	(560.3)	(531.8)
Accumulated intangible asset impairment and other charges	(52.7)	(52.7)
Total purchased intangible assets, net	33.9	62.4
Amortization of intangible assets	28.5	36.3	$ 31.9
Acceleration of the end of life of certain intangible assets, finite-lived	5.6
Intangible assets no longer utilized		20.0
Impairment of intangible assets			0.0
Cost of revenues [Member]
Purchased Intangible Assets [Line Items]
Amortization of intangible assets	24.6	30.9	27.3
Cost of revenues [Member] | Intangible Asset Write-Down [Member] | Restructuring Plan 2014 [Member]
Purchased Intangible Assets [Line Items]
Impairment of intangible assets		19.3
Selling and marketing [Member]
Purchased Intangible Assets [Line Items]
Amortization of intangible assets	2.8	4.2	3.4
General and administrative [Member]
Purchased Intangible Assets [Line Items]
Amortization of intangible assets	1.1	1.2	1.2
Operating expenses [Member]
Purchased Intangible Assets [Line Items]
Amortization of intangible assets	3.9	5.4	$ 4.6
Restructuring and Other Charges [Member] | Intangible Asset Write-Down [Member] | Restructuring Plan 2014 [Member]
Purchased Intangible Assets [Line Items]
Impairment of intangible assets		0.7
Technologies and patents [Member]
Purchased Intangible Assets [Line Items]
Gross	567.7	567.7
Accumulated amortization	(491.8)	(466.1)
Impairment and other charges	(49.9)	(49.9)
Net	26.0	51.7
Customer Contracts, Support Agreements, and Related Relationships [Member]
Purchased Intangible Assets [Line Items]
Gross	78.1	78.1
Accumulated amortization	(67.8)	(65.2)
Impairment and other charges	(2.8)	(2.8)
Net	7.5	10.1
Other [Member]
Purchased Intangible Assets [Line Items]
Gross	1.1	1.1
Accumulated amortization	(0.7)	(0.5)
Impairment and other charges	0.0	0.0
Net	$ 0.4	$ 0.6