Fair Value Measurements (Fair Value of Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Millions		12 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Maximum potential payout of acquisition-related contingent consideration		$ 140
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets at fair value		3,292	$ 2,778
Total liabilities at fair value		189	17
Quoted Prices In Active Markets For Identical Financial Instruments (Level 1)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets at fair value		2,382	1,106
Total liabilities at fair value		11	9
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets at fair value		910	1,672
Total liabilities at fair value		56	8
Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets at fair value		0	0
Total liabilities at fair value		122	0
Short-Term Investments [Member] | Quoted Prices In Active Markets For Identical Financial Instruments (Level 1) | U.S. Treasury Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, Available-for-sale of securities		210
Short-Term Investments [Member] | Significant Other Observable Inputs (Level 2) [Member] | Foreign Government Debt Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, Available-for-sale of securities			113
Short-Term Investments [Member] | Significant Other Observable Inputs (Level 2) [Member] | Certificates of Deposit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, Available-for-sale of securities		2
Short-Term Investments [Member] | Significant Other Observable Inputs (Level 2) [Member] | Asset-backed Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value			135
Short-Term Investments And Cash Equivalents [Member] | Quoted Prices In Active Markets For Identical Financial Instruments (Level 1) | U.S. Treasury Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, Available-for-sale of securities			460
Short-Term Investments And Cash Equivalents [Member] | Significant Other Observable Inputs (Level 2) [Member] | Corporate Bonds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, Available-for-sale of securities		624	963
Short-Term Investments And Cash Equivalents [Member] | Significant Other Observable Inputs (Level 2) [Member] | US Agencies Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, Available-for-sale of securities		78	172
Short-Term Investments And Cash Equivalents [Member] | Significant Other Observable Inputs (Level 2) [Member] | Commercial Paper [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, Available-for-sale of securities		150	270
Short-Term Investments And Cash Equivalents [Member] | Significant Other Observable Inputs (Level 2) [Member] | Foreign Government Debt Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, Available-for-sale of securities		52
Cash Equivalents [Member] | Quoted Prices In Active Markets For Identical Financial Instruments (Level 1) | Bank Time Deposits [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, Cash equivalents		286	233
Cash Equivalents [Member] | Quoted Prices In Active Markets For Identical Financial Instruments (Level 1) | Money Market Funds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, Cash equivalents		1,876	405
Other Current Assets and Other Assets [Domain] | Significant Other Observable Inputs (Level 2) [Member] | Foreign Currency Derivatives [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, Foreign currency derivatives, assets		4	19
Other Assets [Member] | Quoted Prices In Active Markets For Identical Financial Instruments (Level 1) | Deferred compensation plan assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, Deferred compensation plan assets and liabilities		10	8
Accrued And Other Current Liabilities And Other Liabilities [Member] | Fair Value, Inputs, Level 3 [Member] | Contingent Consideration [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, Contingent consideration	[1]	122
Accrued and Other Current Liabilities [Member] | Significant Other Observable Inputs (Level 2) [Member] | Foreign Currency Derivatives [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, Foreign currency derivatives, liabilities		56	8
Other Liabilities [Members] | Quoted Prices In Active Markets For Identical Financial Instruments (Level 1) | Deferred Compensation Plan Liabilities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, Deferred compensation plan assets and liabilities		11	9
Other Liabilities [Members] | Fair Value, Inputs, Level 3 [Member] | Contingent Consideration [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, Contingent consideration		$ 122	$ 0
Respawn Entertainment, LLC [Member] | Minimum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Inputs, Discount Rate		3.00%
Respawn Entertainment, LLC [Member] | Maximum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Inputs, Discount Rate		4.00%

[1] The contingent consideration represents the estimated fair value of the additional variable cash consideration payable in connection with our acquisition of Respawn Entertainment, LLC (“Respawn”) that is contingent upon the achievement of certain performance milestones. We estimated fair value using a probability-weighted income approach combined with a real options methodology and applied a discount rate that appropriately captures the risk associated with the obligation. The discount rates used ranged from 3.25 percent to 3.56 percent. See Note 6 for additional information regarding the Respawn acquisition.