Goodwill and Purchased Intangible Assets, Finite Lived Intangible Assets by Class (Details) (USD $)	3 Months Ended				9 Months Ended
	Sep. 30, 2011		Sep. 30, 2010		Sep. 30, 2011		Sep. 30, 2010		Dec. 31, 2010
Purchased Intangible Assets [Line Items]
Finite-lived intangible assets, gross	$ 585,900,000				$ 585,900,000				$ 557,500,000
Finite-lived intangible assets, accumulated amortization	(463,800,000)				(463,800,000)				(443,600,000)
Finite-lived intangible assets, net	122,100,000				122,100,000				113,900,000
Indefinite-lived Intangible Assets	7,900,000				7,900,000				7,900,000
Indefinite-Lived Intangible Assets (Excluding Goodwill)	7,900,000				7,900,000				7,900,000
Intangible Assets Gross Excluding Goodwill	593,800,000				593,800,000				565,400,000
Purchased Intangible Assets, Accumulated Amortization	(463,800,000)				(463,800,000)				(443,600,000)
Purchased intangible assets, net	130,034,000				130,034,000				121,803,000
Amortization of purchased intangible assets	6,700,000	[1]	2,400,000	[1]	20,200,000	[1]	5,000,000	[1]
Impairment of finite-lived intangible assets	0		0		0		0
Total Finite and Indefinite-lived Intangible Assets, Acquired During the Period	0		26,600,000		28,400,000		38,800,000
Technologies and Patents [Member]
Purchased Intangible Assets [Line Items]
Finite-lived intangible assets, gross	494,400,000				494,400,000				471,100,000
Finite-lived intangible assets, accumulated amortization	(398,300,000)				(398,300,000)				(381,400,000)
Finite-lived intangible assets, net	96,100,000				96,100,000				89,700,000
Other Intangible Assets [Member]
Purchased Intangible Assets [Line Items]
Finite-lived intangible assets, gross	91,500,000				91,500,000				86,400,000
Finite-lived intangible assets, accumulated amortization	(65,500,000)				(65,500,000)				(62,200,000)
Finite-lived intangible assets, net	$ 26,000,000				$ 26,000,000				$ 24,200,000

[1] Amount includes amortization expense of purchased intangible assets in operating expenses and in cost of revenues.