Goodwill and Purchased Intangible Assets, Purchased Intangible Assets (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Purchased Intangible Assets [Line Items]
Finite-lived intangible assets, net	$ 30.6
Total purchased intangible assets, gross	646.9	$ 646.9
Total purchased intangible assets, accumulated amortization	(563.6)	(560.3)
Total purchased intangible assets, impairments and other charges	(52.7)	(52.7)
Total purchased intangible assets, net	30.6	33.9
Technologies and patents [Member]
Purchased Intangible Assets [Line Items]
Finite-lived intangible assets, gross	567.7	567.7
Finite-lived intangible assets, accumulated amortization	(494.4)	(491.8)
Finite-lived intangible assets, impairments and other charges	(49.9)	(49.9)
Finite-lived intangible assets, net	23.4	26.0
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	(68.4)	(67.8)
Finite-lived intangible assets, impairments and other charges	(2.8)	(2.8)
Finite-lived intangible assets, net	6.9	7.5
Other intangible assets [Member]
Purchased Intangible Assets [Line Items]
Finite-lived intangible assets, gross	1.1	1.1
Finite-lived intangible assets, accumulated amortization	(0.8)	(0.7)
Finite-lived intangible assets, impairments and other charges	0.0	0.0
Finite-lived intangible assets, net	$ 0.3	$ 0.4