Stock Based Compensation Equity Incentive Plans (Details) (USD $)	12 Months Ended
	Jan. 25, 2015		Jan. 26, 2014	Jan. 27, 2013
Amended and Restated 2007 Equity Incentive Plan
Increased number of shares by Amended 2007 Plan	10,000,000
Number of shares may be issued under the Restated 2007 Plan	187,767,766
Number of Shares Available for Grant	24,501,781		24,700,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	4 years 0 months 0 days
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%
Options expiration period	10
1998 and 2012 employee Stock Purchase Plan
Number Of Shares Authorized Under1998 ESPP				78,000,000
Stock Issued During Period, Shares, 1998 Plan, Prior to the effective date				54,567,667
Maximum number of shares subject to outstanding purchase rights granted under the 1998 Plan that would have returned to the 1998 Plan				15,000,000
Maximum shares available for future offerings under the 1998 Plan as of the effective date of the 2012 Plan				8,432,333
Maximum Aggregated Number of Shares under 2012 ESPP				55,432,333
Shares issued during period under 1998 Plan			8,819	2,687,698
Available but reserved shares for future issuance under 1998 Plan				183,000
Shares remaining in the 1998 ESPP moved to the 2012 ESPP			174,181	12,129,302
Shares increased under Restated 2012 ESPP	12,500,000
Shares purchased under ESPP	6,672,000		6,124,000	5,463,000
Total shares purchased under 2012 ESPP	12,787,748
Shares reserved for future issuance under 2012 Plan	52,448,068		65,235,816
Offering and purchase period under ESPP	24 months, which is divided into four purchase periods of six months
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	21,345,000		32,504,000
Stock Options granted (in shares)	86,000		6,149,000	7,119,000
Options, Exercises in Period	(9,795,000)
Options, Forfeitures in Period	(1,450,000)
Options, Outstanding, Weighted Average Exercise Price	$ 14.61		$ 14.22
Options, Grants in Period, Weighted Average Exercise Price	$ 18.75
Options, Exercises in Period, Weighted Average Exercise Price	$ 12.64
Options, Forfeitures in Period, Weighted Average Exercise Price	$ 19.27
Options, Exercisable, Number	15,120,000
Options, Exercisable, Weighted Average Exercise Price	$ 14.70
Options, Vested and Expected to Vest, Outstanding, Number	20,356,000
Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price	$ 14.62
Options, Outstanding, Weighted Average Remaining Contractual Term	5 years 10 months 24 days
Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	5 years 1 month 5 days
Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term	5 years 9 months 17 days
Options, Outstanding, Intrinsic Value	$ 130,923,000	[1]
Options, Exercisable, Intrinsic Value	91,434,000	[1]
Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value	124,575,000	[1]
Entity Closing Stock Price	20.71
Outstanding Options In Money	21,100,000
Exercisable Options In Money	14,900,000
Minimum number of PSUs issuable	1,300,000
Maximum number of PSUs issuable	2,500,000
Options, Exercises in Period, Total Intrinsic Value	61,900,000		14,400,000	21,100,000
Total fair value of Options, Vested in Period	32,600,000		34,600,000	40,300,000
RSUs and PSUs
Retricteds stock units, outstanding, Number	23,275,000		18,852,000
Restricted stock units granted (in shares)	12,912,000	[2]	10,757,000	8,136,000
Restricted stock units, Vested in Period	(7,163,000)
Restricted stock units, Forfeited in Period	(1,326,000)
Weighted Average Grant Date Fair Value, RSUs, Outstanding	$ 15.94		$ 13.82
Weighted average grant date fair value, RSUs and PSUs, granted	$ 17.68		$ 13.46	$ 13.86
Restricted stock units, Vested in Period, Weighted Average Grant Date Fair Value	$ 13.78
Restricted stock units, Forfeited in Period, Weighted Average Grant Date Fair Value	$ 14.44
Weighted Average Grant Date Fair Value, RSUs and PSUs, Vested and expected to vest	$ 15.96
Aggregate Intrinsic value of RSUs vested and expected to vest	$ 18,988,000
Number of Shares Available for Grant	24,501,781		24,700,000

[1] The aggregate intrinsic value in the table above represents the total pre-tax intrinsic value for in-the-money options at January 25, 2015, based on the $20.71 closing stock price of our common stock on the NASDAQ Global Select Market on January 23, 2015, the last trading day of fiscal year 2015, which would have been received by the option holders had all in-the-money option holders exercised their options as of that date. The total number of in-the-money options outstanding and exercisable as of January 25, 2015 was 21.1 million shares and 14.9 million shares, respectively.

[2] Includes the total number of PSUs issuable if the maximum corporate financial performance target level for fiscal year 2015 is achieved. Depending on the actual level of achievement of the corporate performance target at the end of fiscal year 2015, the range of PSUs issued could be from 1.3 million to 2.5 million shares. The PSUs were granted during the first quarter of fiscal year 2015 to our CEO and senior management as approved by our Compensation Committee.