Stock Based Compensation (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended		9 Months Ended		12 Months Ended
		Oct. 25, 2015	Oct. 26, 2014	Oct. 25, 2015	Oct. 26, 2014	Jan. 25, 2015
Share-based Compensation
Cost of revenue		$ 4	$ 4	$ 10	$ 8
Research and development		28	22	82	65
Sales, general and administrative		19	16	53	42
Stock-based compensation expense		$ 51	42	$ 145	115
Stock Options
Stock options beginning balance (in shares)				21.0
Stock Options granted (in shares)				0.0
Stock options exercised (in shares)				(6.0)
Stock options cancelled (in shares)				0.0
Stock options ending balance (in shares)		15.0		15.0		21.0
Weighted average exercise price of stock options at beginning of period				$ 14.61
Weighted average exercise price of stock options granted				0.00
Weighted average exercise price of stock options exercised				14.48
Weighted average exercise price of stock options cancelled				0.00
Weighted average exercise price of stock options at end of period		$ 14.55		$ 14.55		$ 14.61
RSUs, PSUs, and Market-based PSUs
RSUs and PSUs beginning balance (in shares)				23.0
RSUs, PSUs and mkt-based PSUs granted (in shares)	[1],[2]			13.0
RSUs and PSUs vested (in shares)				(8.0)
RSUs and PSUs cancelled (in shares)				(2.0)
RSUs, PSUs, and mkt-based PSUs ending balance (in shares)		26.0		26.0		23.0
Weighted average grant date fair value of RSUs and PSUs at beginning of period				$ 15.94
Weighted avg grant-date FV of RSUs, PSUs and mkt-based PSUs				21.61
Weighted average grant-date fair value of RSUs and PSUs vested				15.53
Weighted average grant date fair value of RSUs and PSUs cancelled				16.40
Weighted avg grant date FV of RSUs, PSUs and mkt-based PSUs at end of period		$ 18.84		$ 18.84		$ 15.94
Minimum number of PSUs issuable		0.0		0.0
Maximum number of PSUs issuable		2.0		2.0
Minimum number of market-based PSUs issuable		0.0		0.0
Maximum number of market-based PSUs issuable		0.4		0.4
Stock-based compensation expense related to equity awards not expected to vest		$ 34	$ 28	$ 43	$ 35
Summary of unearned SBC expense
Aggregate amount of unearned stock-based compensation expense related to equity awards, adjusted for estimated forfeitures		$ 420		$ 420		$ 291
Employee Stock Option
Summary of unearned SBC expense
Estimated weighted average amortization period				1 year 3 months 28 days		1 year 9 months 18 days
RSUs, PSUs, and Market-based PSUs
Summary of unearned SBC expense
Estimated weighted average amortization period				2 years 11 months 19 days		2 years 9 months 17 days
Employee Stock Purchase Plan
Summary of unearned SBC expense
Estimated weighted average amortization period				9 months		6 months

[1] Includes the market-based PSUs that become eligible to vest if the maximum target for total shareholder return, or TSR, over the 3-year measurement period is achieved. Depending on the ranking of our TSR compared to the respective TSRs of the companies comprising the Standard & Poor’s 500 Index during a 3-year measurement period, the market-based PSUs that become eligible to vest could range from 0 to 0.4 million shares. We granted market-based PSUs during the first quarter of fiscal year 2016 to our CEO and senior management as approved by our Compensation Committee.

[2] Includes the total PSUs that become eligible to vest if the corporate financial performance maximum target level for fiscal year 2016 is achieved. Using an estimate for the level of achievement of the corporate performance target at the end of fiscal year 2016, we are estimating PSUs that become eligible to vest for fiscal year 2016 performance to be in the range of 0 to 2 million shares. We granted PSUs during the first quarter of fiscal year 2016 to our CEO and senior management as approved by our Compensation Committee.