Goodwill and Purchased Intangible Assets, Purchased Intangible Assets (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Purchased Intangible Assets [Line Items]
Finite-lived intangible assets, net	$ 39.2
Total purchased intangible assets, gross	646.9	$ 646.9
Total purchased intangible assets, accumulated amortization	(555.0)	(531.8)
Total purchased intangible assets, impairments and other charges	(52.7)	(52.7)
Total purchased intangible assets, net	39.2	62.4
Technologies and patents [Member]
Purchased Intangible Assets [Line Items]
Finite-lived intangible assets, gross	567.7	567.7
Finite-lived intangible assets, accumulated amortization	(487.2)	(466.1)
Finite-lived intangible assets, impairments and other charges	(49.9)	(49.9)
Finite-lived intangible assets, net	30.6	51.7
Customer contracts, support agreements, and related relationships [Member]
Purchased Intangible Assets [Line Items]
Finite-lived intangible assets, gross	78.1	78.1
Finite-lived intangible assets, accumulated amortization	(67.2)	(65.2)
Finite-lived intangible assets, impairments and other charges	(2.8)	(2.8)
Finite-lived intangible assets, net	8.1	10.1
Other intangible assets [Member]
Purchased Intangible Assets [Line Items]
Finite-lived intangible assets, gross	1.1	1.1
Finite-lived intangible assets, accumulated amortization	(0.6)	(0.5)
Finite-lived intangible assets, impairments and other charges	0.0	0.0
Finite-lived intangible assets, net	$ 0.5	$ 0.6