Goodwill and Purchased Intangible Assets, Finite Lived Intangible Assets by Class (Details) (USD $)	3 Months Ended
	Mar. 31, 2012		Mar. 31, 2011		Dec. 31, 2011
Purchased Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 623,700,000				$ 591,000,000
Finite-Lived Intangible Assets, Accumulated Amortization	(478,000,000)				(470,700,000)
Finite-Lived Intangible Assets, Net	145,700,000				120,300,000
Intangible Assets Gross Excluding Goodwill	630,500,000				593,800,000
Purchased Intangible Assets, Accumulated Amortization	(478,000,000)				(470,700,000)
Intangible Assets, Net (Excluding Goodwill)	152,541,000				123,114,000
Amortization Of Purchased Intangible Assets	7,300,000	[1]	6,700,000	[1]
Impairment of finite-lived intangible assets	0		0
In Process Research And Development [Member]
Purchased Intangible Assets [Line Items]
Indefinite-lived Intangible Assets	6,800,000				2,800,000
Technologies and Patents [Member]
Purchased Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	531,200,000				499,500,000
Finite-Lived Intangible Assets, Accumulated Amortization	(410,500,000)				(404,200,000)
Finite-Lived Intangible Assets, Net	120,700,000				95,300,000
Other Intangible Assets [Member]
Purchased Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	92,500,000				91,500,000
Finite-Lived Intangible Assets, Accumulated Amortization	(67,500,000)				(66,500,000)
Finite-Lived Intangible Assets, Net	$ 25,000,000				$ 25,000,000

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