Stock Based Compensation Equity Incentive Plans (Details) (USD $)	12 Months Ended
	Jan. 27, 2013		Jan. 29, 2012	Jan. 30, 2011	Jan. 31, 2010
2007 Equity Incentive Plan [Abstract]
Number Of Shares Authorized Under 2007 Plan Prior To Stock Splits	101,845,177
Number Of Shares Authorized Under 2007 Plan After Stock Splits	152,767,766
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	36,899,876		22,425,952	33,736,488	44,016,042
Change in vesting period	changed the vesting schedule for stock options and RSUs granted to employees from a three year period to a four year period
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	four
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Date	six or ten
Increased number of shares by Amended 2007 Plan	25,000,000
Number of shares may be issued under the Restated 2007 Plan	177,767,766
Number of Shares Available for Grant under 2007 plan	36,889,121
PortalPlayer, Inc. 1999 Stock Option Plan [Abstract]
Exchange Ratio For Acquired Entity Outstanding Stock Options Rights For Those Of Acquiring Entity	by multiplying the number of shares of PortalPlayer common stock underlying such option by 0.3601
Stock Option Exercise Price Ratio For Assumed Stock Options Rights For Those Of Acquiring Entity	he exercise price per share for each assumed option was similarly adjusted by dividing the exercise price by 0.3601
Incentive Stock Options Minimum Grant Price Percentage Of Common Stock Market Price	1
NonStatutory Stock Options Minimum Grant Price Percentage Of Common Stock Market Price	0.85
1998 Employee Stock Purchase Plan [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Employee Subscription Rate			10.00%
ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumEmployeeSubscriptionRateBoardOfDirectorApproved			0.15
Stock Issued During Period, Shares, Employee Stock Purchase Plans	5,500,000		5,800,000	6,700,000
Stock Issued During Period, Shares, Employee Stock Purchase Plans, Prior to the effective date	54,567,667
GrantDateFairValuePerShareInPeriodGrantsToEmployees	5.16		5.47	4.06
Stock Issued During Period, Shares, New Issues	57,255,365
Share-based Compensation Arrangement by Share-based Payment Award, Per Share Weighted Average Price of Shares Purchased	$ 10.83		$ 8.18	$ 6.59
NumberOfSharesAuthorizedUnder1998EmployeeStockPurchasePlanAfterStockSplits	78,000,000
Shares remaining in the 1998 ESPP moved to the 2012 ESPP	12,129,302
2012 Employee Stock Purchase Plan [Abstract]
Stock Issued During Period, Shares, Employee Stock Purchase Plans, after the effective date	2,687,698
Maximum Aggregated Number of Shares under 2012 ESPP	55,432,333
Newly Requested Shares Under 2012 ESPP	32,000,000
Maximum shares available for future offerings under the 1998 Plan as of the effective date of the 2012 Plan	8,432,333
Maximum number of shares subject to outstanding purchase rights granted under the 1998 Plan that would have returned to the 1998 Plan	15,000,000
Available Number Of Shares under 2012 ESPP	52,561,635
Maximum Offering Period Under ESPP	27
CurrentOfferingPeriodUnderESPP	24
Number of Month in Offering Period Under ESPP	6
Equity Awards, Available For Grant Under Equity Incentive Plans [Abstract]
Total Shares granted during the period (options and RSUs)	(15,254,977)		(13,767,554)	(12,923,659)
Total Shares forfeited (Options and RSUs)	4,728,901		2,457,018	2,644,105
Common Stock, Capital Shares Reserved for Future Issuance	25,000,000	[1]
Stock Options [Abstract]
Options, Forfeitures in Period	(3,806,290)		(1,588,207)	(1,878,447)
Options, Exercises in Period, Total Intrinsic Value	$ 21,100,000		$ 105,300,000	$ 139,100,000
Options, Forfeitures in Period, Weighted Average Exercise Price	$ 17.04		$ 14.78	$ 12.56
Options, Outstanding, Number	32,995,325		33,328,976	44,001,458	58,348,422
Options, Outstanding, Weighted Average Exercise Price	$ 14.66		$ 14.44	$ 12.88	$ 11.30
Options, Outstanding, Weighted Average Remaining Contractual Term	5.08
Options, Outstanding, Intrinsic Value	26,006,026,000	[2]
Retricteds stock units, nonvested, Number	15,159,227		13,637,803	10,611,914	7,488,512
Stock Options granted (in shares)	7,119,319		6,430,778	5,818,966
Options, Exercises in Period, Weighted Average Exercise Price	$ 13.88		$ 16.18	$ 13.79
Options, Exercises in Period	(3,646,680)		(15,515,053)	(18,287,483)
Options, Grants in Period, Weighted Average Exercise Price	$ 8.66		$ 10.70	$ 8.16
Options, Exercisable, Number	20,156,213
Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	3.00
Options, Exercisable, Weighted Average Exercise Price	$ 14.89
Options, Exercisable, Intrinsic Value	22,850,198,000	[2]
Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price	$ 14.68
Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term	4.86
Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value	$ 25,520,514,000	[2]
EntityClosingStockPrice	$ 12.41
OustandingOptionsInMoney	26,700,000
ExercisableOptionsInMoney	9,600,000
Restricted Stock Units [Abstract]
Restricted stock units, Vested in Period, Weighted Average Grant Date Fair Value	$ 15.02		$ 12.02	$ 11.74
Restricted stock units granted (in shares)	8,135,658		7,336,776	7,104,693
Restricted stock units, Nonvested, Weighted Average Grant Date Fair Value	$ 14.46		$ 15.10	$ 13.23	$ 12.28
Weighted average grant date fair value of restricted stock units granted	$ 13.86		$ 16.31	$ 13.61
Restricted stock units, Forfeited in Period	(922,611)		(868,811)	(765,658)
Restricted stock units, Forfeited in Period, Weighted Average Grant Date Fair Value	$ 15.14		$ 14.72	$ 13.76
Restricted stock units, Vested in Period	(5,691,623)		(3,442,076)	(3,215,633)
Restricted stock units Vested and Expected To Vest Weighted Average Grant Date Fair Value	$ 14.46
Restricted Stock Units (RSUs) [Member]
2007 Equity Incentive Plan [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights	25% vesting on a pre-determined date that is close to the anniversary of the date of grant and 12.5% vesting semi-annually thereafter until fully vested.
Stock Options [Abstract]
Options, Vested and Expected to Vest, Outstanding, Number	12,245,083
Stock Options
2007 Equity Incentive Plan [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights	25% vesting on the anniversary of the hire date in the case of new hires or the anniversary of the date of grant in the case of grants to existing employees and 6.25% vesting at the end of each quarterly period thereafter
Stock Options [Abstract]
Options, Vested and Expected to Vest, Outstanding, Number	30,971,523
Employee Stock Purchase Plan
2007 Equity Incentive Plan [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	183,000
Portal Player 1999 Stock Option Plan [Member]
2007 Equity Incentive Plan [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights	25% on the first anniversary of the grant date of the option, and an additional 1/48th of the shares upon completion of each succeeding full month of continuous employment thereafter.
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Date	ten

[1] Represents the shares that were approved at our 2012 Annual Meeting of Stockholders.

[2] The aggregate intrinsic value in the table above represents the total pre-tax intrinsic value for in-the-money options at January 27, 2013, based on the $12.41 closing stock price of our common stock on the NASDAQ Global Select Market on January 25, 2013, the last trading day of fiscal year 2013, 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 27, 2013 was 26.7 million shares and 9.6 million shares, respectively.