Goodwill and Purchased Intangible Assets, Purchased Intangible Assets (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Purchased Intangible Assets [Line Items]
Finite-lived intangible assets, net	$ 50.5
Total purchased intangible assets, gross	646.9	646.9
Total purchased intangible assets, accumulated amortization	(543.7)	(531.8)
Total purchased intangible assets, impairments and other charges	(52.7)	(52.7)
Total purchased intangible assets, net	50.5	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	(477.2)	(466.1)
Finite-lived intangible assets, impairments and other charges	(49.9)	(49.9)
Finite-lived intangible assets, net	40.6	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	(66.0)	(65.2)
Finite-lived intangible assets, impairments and other charges	(2.8)	(2.8)
Finite-lived intangible assets, net	9.3	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	(0.5)	(0.5)
Finite-lived intangible assets, impairments and other charges	0	0
Finite-lived intangible assets, net	$ 0.6	$ 0.6