(Fair Value Of Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
	Sep. 30, 2013	Mar. 31, 2013	Sep. 30, 2013 Fair Value	Mar. 31, 2013 Fair Value	Sep. 30, 2013 Quoted Prices In Active Markets For Identical Financial Instruments (Level 1)	Mar. 31, 2013 Quoted Prices In Active Markets For Identical Financial Instruments (Level 1)	Sep. 30, 2013 Significant Other Observable Inputs (Level 2)	Mar. 31, 2013 Significant Other Observable Inputs (Level 2)	Sep. 30, 2013 Significant Unobservable Inputs (Level 3)	Mar. 31, 2013 Significant Unobservable Inputs (Level 3)	Sep. 30, 2013 Significant Unobservable Inputs (Level 3) Contingent consideration	Mar. 31, 2013 Significant Unobservable Inputs (Level 3) Contingent consideration	Mar. 31, 2012 Significant Unobservable Inputs (Level 3) Contingent consideration	Sep. 30, 2013 Cash Equivalents Fair Value Money market funds	Mar. 31, 2013 Cash Equivalents Fair Value Money market funds	Sep. 30, 2013 Cash Equivalents Quoted Prices In Active Markets For Identical Financial Instruments (Level 1) Money market funds	Mar. 31, 2013 Cash Equivalents Quoted Prices In Active Markets For Identical Financial Instruments (Level 1) Money market funds	Mar. 31, 2013 Short-Term Investments And Cash Equivalents Fair Value U.S. agency securities	Mar. 31, 2013 Short-Term Investments And Cash Equivalents Fair Value U.S. Treasury securities	Sep. 30, 2013 Short-Term Investments And Cash Equivalents Fair Value Commercial paper	Mar. 31, 2013 Short-Term Investments And Cash Equivalents Fair Value Commercial paper	Mar. 31, 2013 Short-Term Investments And Cash Equivalents Quoted Prices In Active Markets For Identical Financial Instruments (Level 1) U.S. Treasury securities	Mar. 31, 2013 Short-Term Investments And Cash Equivalents Significant Other Observable Inputs (Level 2) U.S. agency securities	Sep. 30, 2013 Short-Term Investments And Cash Equivalents Significant Other Observable Inputs (Level 2) Commercial paper	Mar. 31, 2013 Short-Term Investments And Cash Equivalents Significant Other Observable Inputs (Level 2) Commercial paper	Sep. 30, 2013 Short-Term Investments Fair Value Corporate bonds	Mar. 31, 2013 Short-Term Investments Fair Value Corporate bonds	Sep. 30, 2013 Short-Term Investments Fair Value U.S. agency securities	Sep. 30, 2013 Short-Term Investments Fair Value U.S. Treasury securities	Sep. 30, 2013 Short-Term Investments Quoted Prices In Active Markets For Identical Financial Instruments (Level 1) U.S. Treasury securities	Sep. 30, 2013 Short-Term Investments Significant Other Observable Inputs (Level 2) Corporate bonds	Mar. 31, 2013 Short-Term Investments Significant Other Observable Inputs (Level 2) Corporate bonds	Sep. 30, 2013 Short-Term Investments Significant Other Observable Inputs (Level 2) U.S. agency securities	Sep. 30, 2013 Other assets Fair Value Deferred compensation plan assets		Mar. 31, 2013 Other assets Fair Value Deferred compensation plan assets		Sep. 30, 2013 Other assets Quoted Prices In Active Markets For Identical Financial Instruments (Level 1) Deferred compensation plan assets		Mar. 31, 2013 Other assets Quoted Prices In Active Markets For Identical Financial Instruments (Level 1) Deferred compensation plan assets		Sep. 30, 2013 Other current assets Fair Value Foreign currency derivatives	Mar. 31, 2013 Other current assets Fair Value Foreign currency derivatives	Sep. 30, 2013 Other current assets Significant Other Observable Inputs (Level 2) Foreign currency derivatives	Mar. 31, 2013 Other current assets Significant Other Observable Inputs (Level 2) Foreign currency derivatives	Sep. 30, 2013 Accrued And Other Current Liabilities And Other Liabilities Fair Value Contingent consideration		Mar. 31, 2013 Accrued And Other Current Liabilities And Other Liabilities Fair Value Contingent consideration		Sep. 30, 2013 Accrued And Other Current Liabilities And Other Liabilities Significant Unobservable Inputs (Level 3) Contingent consideration		Mar. 31, 2013 Accrued And Other Current Liabilities And Other Liabilities Significant Unobservable Inputs (Level 3) Contingent consideration		Sep. 30, 2013 Accrued and Other Current Liabilities Fair Value Foreign currency derivatives	Sep. 30, 2013 Accrued and Other Current Liabilities Significant Other Observable Inputs (Level 2) Foreign currency derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value, Cash equivalents														$ 253	$ 469	$ 253	$ 469
Fair value, Available-for-sale of securities																		91	88	42	73	88	91	42	73	179	178	58	54	54	179	178	58
Fair value, Deferred compensation plan assets																																		12	[1]	11	[1]	12	[1]	11	[1]
Fair value, Foreign currency derivatives, assets																																										1	6	1	6
Total assets at fair value			599	916	319	568	280	348
Fair value, Contingent consideration																																														2	[2]	43	[2]	2	[2]	43	[2]
Fair value, Foreign currency derivatives, liabilities																																																						4	4
Total liabilities at fair value			6	43			4		2	43
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value											2	43	112
Average Weighted Average Discount Rate	16.00%	13.00%
Maximum potential payout of acquisition-related contingent consideration	$ 560	$ 566

[1] The deferred compensation plan assets consist of various mutual funds.

[2] The contingent consideration as of September 30, 2013 and March 31, 2013 represents the estimated fair value of the additional variable cash consideration payable primarily in connection with our acquisitions of PopCap Games, Inc. (“PopCap”), KlickNation Corporation (“KlickNation”), and Chillingo Limited (“Chillingo”) that are contingent upon the achievement of certain performance milestones. We estimated the fair value of the acquisition-related contingent consideration payable using probability-weighted discounted cash flow models, and applied a discount rate that appropriately captures the risk associated with the obligation. The weighted average of the discount rates used during the six months ended September 30, 2013 was 16 percent. The weighted average of the discount rates used during the fiscal year 2013 was 13 percent. The significant unobservable input used in the fair value measurement of the contingent consideration payable are forecasted earnings. Significant changes in forecasted earnings would result in a significantly higher or lower fair value measurement. At September 30, 2013 and March 31, 2013, the fair market value of acquisition-related contingent consideration totaled $2 million and $43 million, respectively, compared to a maximum potential payout of $560 million and $566 million, respectively. (c)The change in