Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jul. 26, 2015	Jul. 27, 2014	Jul. 26, 2015	Jul. 27, 2014	Jan. 25, 2015
Amortizable intangible assets components
Amortization expense	$ 19	$ 19	$ 38	$ 38
Future amortization expense associated with intangible assets
Remainder of fiscal 2016	35		35
Fiscal 2017	65		65
Fiscal 2018	50		50
Fiscal 2019	22		22
Fiscal 2020	13		13
Fiscal 2021 and beyond	5		5
Acquisition-related intangible assets
Amortizable intangible assets components
Gross Carrying Amount	193		193		$ 189
Accumulated Amortization	(143)		(143)		(134)
Net Carrying Amount	50		50		55
Patents and Licensed Technology
Amortizable intangible assets components
Gross Carrying Amount	451		451		449
Accumulated Amortization	(311)		(311)		(282)
Net Carrying Amount	140		140		167
Total intangible assets
Amortizable intangible assets components
Gross Carrying Amount	644		644		638
Accumulated Amortization	(454)		(454)		(416)
Net Carrying Amount	$ 190		$ 190		$ 222