Intangible Assets (Details) (USD $)	12 Months Ended
	Jan. 26, 2014	Jan. 27, 2013	Jan. 29, 2012
Amortizable intangible assets components [Line Items]
Gross Carrying Amount	$ 635,435,000	$ 579,041,000
Accumulated Amortization	(339,423,000)	(266,709,000)
Net Carrying Amount	296,012,000	312,332,000
Amortization expense associated with intangible assets
Amortization expense	72,700,000	68,400,000	59,000,000
Future amortization expense associated with intangible assets
Fiscal 2015	79,400,000
Fiscal 2016	72,700,000
Fiscal 2017	59,400,000
Fiscal 2018	48,100,000
Fiscal 2019	19,900,000
Future amortization after year five	16,500,000
Acquisition-related intangible assets
Amortizable intangible assets components [Line Items]
Gross Carrying Amount	189,239,000	172,039,000
Accumulated Amortization	(114,104,000)	(96,389,000)
Net Carrying Amount	75,135,000	75,650,000
Finite-Lived Intangible Assets, Average Useful Life	6 years 6 months 0 days	6 years 10 months 24 days
Patents and Licensed Technology
Amortizable intangible assets components [Line Items]
Gross Carrying Amount	446,196,000	407,002,000
Accumulated Amortization	(225,319,000)	(170,320,000)
Net Carrying Amount	$ 220,877,000	$ 236,682,000
Finite-Lived Intangible Assets, Average Useful Life	7 years 2 months 12 days	7 years 0 months 0 days