Fair Value Measurements (Fair Value of Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) $ in Millions		Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets at fair value		$ 3,797	$ 3,292
Total liabilities at fair value		164	189
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		3,032	2,382
Total liabilities at fair value		12	11
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets at fair value		765	910
Total liabilities at fair value		16	56
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		136	122
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] | Corporate Bonds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, Available-for-sale of securities			624
Short-Term Investments [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
Short-Term Investments [Member] | Significant Other Observable Inputs (Level 2) [Member] | Debt Security, Government, Non-US [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, Available-for-sale of securities			52
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		294
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		327
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		57
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		233	150
Short-Term Investments And Cash Equivalents [Member] | Significant Other Observable Inputs (Level 2) [Member] | Debt Security, Government, Non-US [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, Available-for-sale of securities		58
Short-Term Investments And Cash Equivalents [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 And Cash Equivalents [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		55
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		23	286
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		2,704	1,876
Cash Equivalents [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
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		33	4
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	[1]	11	10
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	[2]	136
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		16	56
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	[1]	12	11
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		$ 136	$ 122	[2]
Minimum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Business Combination, Contingent Consideration, Liability, Measurement Input		0.0292	0.033
Maximum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Business Combination, Contingent Consideration, Liability, Measurement Input		0.0308	0.036

[1] The Deferred Compensation Plan assets consist of various mutual funds. See Note 15 for additional information regarding our Deferred Compensation Plan.

[2] 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. At March 31, 2019, the discount rates used ranged from 2.9 percent to 3.1 percent. See Note 7 for additional information regarding the Respawn acquisition. At March 31, 2018, the discount rates used ranged from 3.3 percent to 3.6 percent.