Stock Based Compensation Equity Incentive Plans (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Jan. 31, 2016	Jan. 25, 2015	Jan. 26, 2014
Amended and Restated 2007 Equity Incentive Plan
Number of shares may be issued under the Restated 2007 Plan	187,767,766
Number of Shares Available for Grant	13,538,400	25,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage	25.00%
Quarterly vesting schedule - options	6.25%
Semi-annual vesting schedule - RSUs	12.50%
Maximum issuable shares of Market-based PSUs, percentage	100.00%
2012 employee Stock Purchase Plan
Maximum Aggregated Number of Shares under 2012 ESPP	65,235,816
Total shares purchased under ESPP	18,459,901
Shares reserved for future issuance under 2012 Plan	46,775,915
Maximum employee subscription rate	10.00%
Potential maximum employee subscription rate by BOD approval	15.00%
Purchase price of ESPP, percent	85.00%
Stock Options
Options, Outstanding, Number	13,000,000	21,000,000
Options, Exercises in Period	(7,000,000)
Options, Forfeitures in Period	(1,000,000)
Options, Outstanding, Weighted Average Exercise Price	$ 14.49	$ 14.61
Options, Exercises in Period, Weighted Average Exercise Price	14.60
Options, Forfeitures in Period, Weighted Average Exercise Price	$ 17.28
Options, Exercisable, Number	11,000,000
Options, Exercisable, Weighted Average Exercise Price	$ 14.51
Options, Vested and Expected to Vest, Outstanding, Number	13,000,000
Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price	$ 14.50
Options, Outstanding, Weighted Average Remaining Contractual Term	5 years 10 months 24 days
Options,Exercisable Options, Weighted Average Remaining Contractual Term	5 years 7 months 5 days
Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term	5 years 9 months 17 days
Options, Outstanding, Intrinsic Value	$ 197
Options, Exercisable, Intrinsic Value	159
Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value	$ 191
RSUs, PSUs, and Market-Based PSUs
RSUs, PSUs and Market-based PSUs, outstanding, Number	26,000,000	23,000,000
RSUs, PSUs and Market-based PSUs, granted (in shares)	13,000,000	13,000,000	11,000,000
RSUs, PSUs and Market-based PSUs, Vested in Period	(8,000,000)
RSUs, PSUs and Market-based PSUs, Forfeited in Period	(2,000,000)
Weighted Average Grant Date Fair Value, RSUs, PSUs and Market-based PSUs, Outstanding	$ 19.12	$ 15.94
Weighted average grant date fair value, RSUs, PSUs, and Market-based PSUs, granted	22.01	$ 17.68	$ 13.46
RSUs, PSUs and Market-based PSUs, Vested in Period, Weighted Average Grant Date Fair Value	15.56
RSUs, PSUs and Market-based PSUs, Forfeited in Period, Weighted Average Grant Date Fair Value	$ 16.63
Aggregate Intrinsic value of RSUs, PSUs and Market-based PSUs, vested and expected to vest	$ 22
Weighted Average Grant Date Fair Value, RSUs, PSUs and Market-based PSUs, Vested and expected to vest	$ 19.14
Minimum number of Market-based PSUs issuable	0
Maximum number of market-based PSUs issuable	400,000
Closing Share Price	$ 29.29
Number of Shares Available for Grant	13,538,400	25,000,000
Options, Exercises in Period, Total Intrinsic Value	$ 75	$ 62	$ 14
Total fair value of Options, Vested in Period	$ 17	$ 33	$ 35