| **Derivative Financial Instruments**                                    | 9 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               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| **Derivative Instruments and Hedging Activities Disclosure [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       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| Derivative Financial Instruments                                        | (4) DERIVATIVE FINANCIAL INSTRUMENTSThe assets or liabilities associated with our derivative instruments and hedging activities are recorded at fair value in other current assets or accrued and other current liabilities, respectively, on our Condensed Consolidated Balance Sheets. As discussed below, the accounting for gains and losses resulting from changes in fair value depends on the use of the derivative instrument and whether it is designated and qualifies for hedge accounting.We transact business in various foreign currencies and have significant international sales and expenses denominated in foreign currencies, subjecting us to foreign currency risk. We purchase foreign currency forward contracts, generally with maturities of 15 months or less, to reduce the volatility of cash flows primarily related to forecasted revenue and expenses denominated in certain foreign currencies. Our cash flow risks are primarily related to fluctuations in the Euro, British pound sterling, Canadian dollar, and Swedish krona. In addition, we utilize foreign currency forward contracts to mitigate foreign exchange rate risk associated with foreign-currency-denominated monetary assets and liabilities, primarily intercompany receivables and payables. The foreign currency forward contracts not designated as hedging instruments generally have a contractual term of approximately 3 months or less and are transacted near month-end. We do not use foreign currency forward contracts for speculative or trading purposes. Cash Flow Hedging ActivitiesCertain of our forward contracts are designated and qualify as cash flow hedges. The effectiveness of the cash flow hedge contracts, including time value, is assessed monthly using regression analysis, as well as other timing and probability criteria. To qualify for hedge accounting treatment, all hedging relationships are formally documented at the inception of the hedges and must be highly effective in offsetting changes to future cash flows on hedged transactions.  The derivative assets or liabilities associated with our hedging activities are recorded at fair value in other current assets or accrued and other liabilities on our Condensed Consolidated Balance Sheets. The effective portion of gains or losses resulting from changes in the fair value of these hedges is initially reported, net of tax, as a component of accumulated other comprehensive income in stockholders’ equity. The gross amount of the effective portion of gains or losses resulting from changes in the fair value of these hedges is subsequently reclassified into net revenue or research and development expenses, as appropriate, in the period when the forecasted transaction is recognized in our Condensed Consolidated Statements of Operations. In the event that the gains or losses in accumulated other comprehensive income are deemed to be ineffective, the ineffective portion of gains or losses resulting from changes in fair value, if any, is reclassified to interest and other income (expense), net, in our Condensed Consolidated Statements of Operations. In the event that the underlying forecasted transactions do not occur, or it becomes remote that they will occur, within the defined hedge period, the gains or losses on the related cash flow hedges are reclassified from accumulated other comprehensive income to interest and other income (expense), net, in our Condensed Consolidated Statements of Operations.Total gross notional amounts and fair values for currency derivatives with cash flow hedge accounting designation are as follows:  As of December 31, 2014 As of March 31, 2014 Notional Amount Fair Value Notional Amount Fair Value  Asset Liability  Asset LiabilityForward contracts to purchase$132 $— $9 $179 $— $3Forward contracts to sell$164 $11 $— $363 $— $2The net impact of the effective portion of gains and losses from our cash flow hedging activities in our Condensed Consolidated Statements of Operations for three months ended December 31, 2014 and 2013 was immaterial.The net impact of the effective portion of gains and losses from our cash flow hedging activities in our Condensed Consolidated Statements of Operations was a loss of $8 million for the nine months ended December 31, 2014 and a loss of $5 million for the nine months ended December 31, 2013.     During the three and nine months ended December 31, 2014, we reclassified an immaterial amount of the ineffective portion of gains or losses resulting from changes in fair value into interest and other income (expense), net. Balance Sheet Hedging ActivitiesOur foreign currency forward contracts that are not designated as hedging instruments are accounted for as derivatives whereby the fair value of the contracts are reported as other current assets or accrued and other current liabilities on our Condensed Consolidated Balance Sheets, and gains and losses resulting from changes in the fair value are reported in interest and other income (expense), net, in our Condensed Consolidated Statements of Operations. The gains and losses on these foreign currency forward contracts generally offset the gains and losses in the underlying foreign-currency-denominated monetary assets and liabilities, which are also reported in interest and other income (expense), net, in our Condensed Consolidated Statements of Operations. The fair value of our foreign currency forward contracts was measured using Level 2 inputs. Total gross notional amounts and fair values for currency derivatives that are not designated as hedging instruments are accounted for as follows: As of December 31, 2014 As of March 31, 2014 Notional Amount Fair Value Notional Amount Fair Value  Asset Liability  Asset LiabilityForward contracts to purchase$58 $— $— $140 $— $1Forward contracts to sell$361 $4 $— $232 $— $—The effect of foreign currency forward contracts not designated as hedging instruments in our Condensed Consolidated Statements of Operations for the three and nine months ended December 31, 2014 and 2013, was as follows (in millions): Location of Gain (Loss) Recognized in Income onDerivatives Amount of Gain (Loss) Recognized in Income on Derivatives Three Months Ended December 31, Nine Months Ended December 31, 2014 2013 2014 2013Foreign currency forward contracts not designated as hedging instrumentsInterest and other income (expense), net $19 $1 $38 $(4) |

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| - Definition
The entire disclosure for derivative instruments and hedging activities including, but not limited to, risk management strategies, non-hedging derivative instruments, assets, liabilities, revenue and expenses, and methodologies and assumptions used in determining the amounts.
+ References
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