| **Stock-Based Compensation**                                                | 9 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           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| **Share-based Compensation [Abstract]**                                     |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    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| Disclosure of Compensation Related Costs, Share-based Payments [Text Block] | (14) STOCK-BASED COMPENSATIONValuation AssumptionsWe are required to estimate the fair value of share-based payment awards on the date of grant. We recognize compensation costs for stock-based payment awards to employees based on the grant-date fair value using a straight-line approach over the service period for which such awards are expected to vest.We determine the fair value of our share-based payment awards as follows:•Restricted Stock Units, Restricted Stock, and Performance-Based Restricted Stock Units. The fair value of restricted stock units, restricted stock, and performance-based restricted stock units (other than market-based restricted stock units) is determined based on the quoted market price of our common stock on the date of grant. Performance-based restricted stock units include grants made (1) to certain members of executive management primarily granted in fiscal year 2009 and (2) in connection with certain acquisitions.•Market-Based Restricted Stock Units. Market-based restricted stock units consist of grants of performance-based restricted stock units to certain members of executive management that vest contingent upon the achievement of pre-determined market and service conditions (referred to herein as “market-based restricted stock units”). The fair value of our market-based restricted stock units is determined using a Monte-Carlo simulation model. Key assumptions for the Monte-Carlo simulation model are the risk-free interest rate, expected volatility, expected dividends and correlation coefficient.•Stock Options and Employee Stock Purchase Plan. The fair value of stock options and stock purchase rights granted pursuant to our equity incentive plans and our 2000 Employee Stock Purchase Plan (“ESPP”), respectively, is determined using the Black-Scholes valuation model based on the multiple-award valuation method. Key assumptions of the Black-Scholes valuation model are the risk-free interest rate, expected volatility, expected term and expected dividends.The determination of the fair value of market-based restricted stock units, stock options and ESPP is affected by assumptions regarding subjective and complex variables. Generally, our assumptions are based on historical information and judgment is required to determine if historical trends may be indicators of future outcomes.The estimated assumptions used in the Black-Scholes valuation model to value our stock option grants and ESPP were as follows: Stock Option Grants ESPP Three Months EndedDecember 31, Nine Months EndedDecember 31, Nine Months EndedDecember 31, 2013 2012 2013 2012 2013 2012Risk-free interest rate1.6% 0.4 - 1.0% 1.6% 0.4 - 1.0% 0.1% 0.1 - 0.2%Expected volatility37 - 42% 40 - 45% 37 - 42% 40 - 46% 36 - 37% 41 - 42%Weighted-average volatility37% 41% 37% 43% 37% 41%Expected term4.5 years 4.3 years 4.5 years 4.4 years 6 - 12 months 6 - 12 monthsExpected dividendsNone None None None None NoneThe estimated assumptions used in the Monte-Carlo simulation model to value our market-based restricted stock units were as follows:  Three Months Ended December 31, Nine Months Ended December 31, 2012 2013 2012Risk-free interest rate0.3% 0.4% 0.2 - 0.4%Expected volatility33% 16 - 58% 17 - 116%Weighted-average volatility33% 31% 35%Expected dividendsNone None NoneThere were no market-based restricted stock units granted during the three months ended December 31, 2013. Stock-Based Compensation ExpenseEmployee stock-based compensation expense recognized during the three and nine months ended December 31, 2013 and 2012 was calculated based on awards ultimately expected to vest and has been reduced for estimated forfeitures. In subsequent periods, if actual forfeitures differ from those estimates, an adjustment to stock-based compensation expense will be recognized at that time.The following table summarizes stock-based compensation expense resulting from stock options, restricted stock, restricted stock units and the ESPP included in our Condensed Consolidated Statements of Operations (in millions): Three Months Ended December 31, Nine Months Ended December 31, 2013 2012 2013 2012Cost of revenue$— $— $1 $1Research and development (a)25 25 68 72Marketing and sales (a) 7 7 20 23General and administrative (a)8 7 22 26Stock-based compensation expense$40 $39 $111 $122(a)During the fourth quarter of fiscal year 2013, we reviewed our operating expenses and reclassified certain amounts, primarily headcount and facilities costs, to align with our current operating structure. As a result, we also reclassified the related prior year stock-based compensation expense amounts within our Condensed Consolidated Statements of Operations for comparability purposes. These reclassifications did not affect the Company’s total stock-based compensation expense. During the three and nine months ended December 31, 2013, we did not recognize any provision for or benefit from income taxes related to our stock-based compensation expense.As of December 31, 2013, our total unrecognized compensation cost related to stock options was $10 million and is expected to be recognized over a weighted-average service period of 3.7 years. As of December 31, 2013, our total unrecognized compensation cost related to restricted stock and restricted stock units (collectively referred to as “restricted stock rights”) was $255 million and is expected to be recognized over a weighted-average service period of 1.7 years. Of the $255 million of unrecognized compensation cost, $16 million relates to market-based restricted stock units.Stock OptionsThe following table summarizes our stock option activity for the nine months ended December 31, 2013: Options(in thousands) Weighted-AverageExercise Price Weighted-AverageRemainingContractual Term(in years) AggregateIntrinsic Value(in millions)Outstanding as of March 31, 20137,802 $34.17    Granted1,010 26.21    Exercised(1,926) 17.95    Forfeited, cancelled or expired(976) 48.48    Outstanding as of December 31, 20135,910 35.72 4.83 $10Vested and expected to vest5,663 36.16 4.62 $10Exercisable as of December 31, 20134,727 38.49 3.69 $8The aggregate intrinsic value represents the total pre-tax intrinsic value based on our closing stock price as of December 31, 2013, which would have been received by the option holders had all the option holders exercised their options as of that date. We issue new common stock from our authorized shares upon the exercise of stock options. Restricted Stock RightsThe following table summarizes our restricted stock rights activity, excluding performance-based and market-based restricted stock unit activity discussed below, for the nine months ended December 31, 2013: Restricted StockRights(in thousands) Weighted-Average GrantDate Fair ValueBalance as of March 31, 201315,918 $16.85Granted6,853 22.67Vested(5,743) 17.30Forfeited or cancelled(2,280) 17.63Balance as of December 31, 201314,748 19.26The weighted-average grant date fair values of restricted stock rights granted during the three and nine months ended December 31, 2013 were $23.22 and $22.67, respectively. Performance-Based Restricted Stock UnitsThe following table summarizes our performance-based restricted stock unit activity for the nine months ended December 31, 2013:  Performance-Based RestrictedStock Units(in thousands) Weighted-Average GrantDate Fair ValueBalance as of March 31, 20131,324 $51.54Vested(36) 15.39Forfeited or cancelled(1,234) 48.32Balance as of December 31, 201354 15.39Market-Based Restricted Stock UnitsOur market-based restricted stock units vest contingent upon the achievement of pre-determined market and service conditions. If these market conditions are not met but service conditions are met, the restricted stock units will not vest; however, any compensation expense we have recognized to date will not be reversed. The number of shares of common stock to be received at vesting will range from zero percent to 200 percent of the target number of stock units based on our total stockholder return (“TSR”) relative to the performance of companies in the NASDAQ-100 Index for each measurement period, generally over a three year period. We present shares granted at 100 percent of target of the number of stock units that may potentially vest. The maximum number of common shares that could vest is approximately 1.1 million for market-based restricted stock units granted during the nine months ended December 31, 2013. As of December 31, 2013, the maximum number of shares that could vest is approximately 1.9 million for market-based restricted stock units outstanding.The following table summarizes our market-based restricted stock unit activity for the nine months ended December 31, 2013.  Market-BasedRestricted StockUnits(in thousands) Weighted-Average GrantDate Fair ValueBalance as of March 31, 2013925 $19.16Granted555 29.52Vested(304) 16.01Forfeited or cancelled(222) 23.47Balance as of December 31, 2013954 25.19Stock Repurchase ProgramIn February 2011, our Board of Directors authorized a program to repurchase up to $600 million of our common stock over the following 18 months. We completed that program in April 2012. We repurchased approximately 32 million shares in the open market under that program, including pursuant to pre-arranged stock trading plans. During three months ended June 30, 2012, we repurchased and retired approximately 4 million shares of our common stock for approximately $71 million under that program.In July 2012, our Board of Directors authorized a program to repurchase up to $500 million of our common stock. Under this program, we may purchase stock in the open market or through privately-negotiated transactions in accordance with applicable securities laws, including pursuant to pre-arranged stock trading plans. The timing and actual amount of the stock repurchases will depend on several factors including price, capital availability, regulatory requirements, alternative investment opportunities and other market conditions. We are not obligated to repurchase any specific number of shares under this program and it may be modified, suspended or discontinued at any time. During the three months ended December 31, 2012, we repurchased and retired approximately 12.2 million shares of our common stock for approximately $157 million under this new program. During the nine months ended December 31, 2012, we repurchased and retired approximately 24.9 million shares of our common stock for approximately $336 million.During the three and nine months ended December 31, 2013, we did not repurchase any shares of our common stock.Annual Meeting of StockholdersAt our Annual Meeting of Stockholders, held on July 31, 2013, our stockholders approved (a) amendments to our 2000 Equity Incentive Plan (the “Equity Plan”) to increase the number of shares of common stock authorized under the Equity Plan by 18 million shares, and to increase the limit on the number of shares that may be covered by equity awards to new employees under the Equity Plan from a maximum of 2 million shares in the fiscal year of hire to 4 million shares in the fiscal year of hire, and (b) an amendment to the ESPP to increase the number of shares authorized under the ESPP by 7 million shares. |

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| - Definition
The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5047-113901Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 50 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6406099&loc=d3e25284-112666Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 40 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6418621&loc=d3e17540-113929Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5444-113901Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 14
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