(Fair Value Of Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Millions	Jun. 30, 2021	Mar. 31, 2021
Quoted Prices In Active Markets For Identical Financial Instruments (Level 1)
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Total assets at fair value	$ 1,033	$ 2,712
Total liabilities at fair value	22	19
Significant Other Observable Inputs (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Total assets at fair value	709	778
Total liabilities at fair value	37	40
Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Total assets at fair value	0	0
Total liabilities at fair value	0	0
Short-term investments | Significant Other Observable Inputs (Level 2) | U.S. agency securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value, Available-for-sale of securities	3	3
Short-term investments | Significant Other Observable Inputs (Level 2) | Debt Security, Government, Non-US [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value, Available-for-sale of securities	63	67
Short-term investments | Significant Other Observable Inputs (Level 2) | Asset-backed Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Asset-backed securities	117	112
Short-term investments | Significant Other Observable Inputs (Level 2) | Certificates of Deposit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value, Available-for-sale of securities	37	41
Short-Term Investments And Cash Equivalents | Quoted Prices In Active Markets For Identical Financial Instruments (Level 1) | U.S. Treasury securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value, Available-for-sale of securities	200	437
Short-Term Investments And Cash Equivalents | Significant Other Observable Inputs (Level 2) | Corporate bonds
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value, Available-for-sale of securities	335	380
Short-Term Investments And Cash Equivalents | Significant Other Observable Inputs (Level 2) | Commercial paper
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value, Available-for-sale of securities	126	142
Cash Equivalents | Quoted Prices In Active Markets For Identical Financial Instruments (Level 1) | Bank Time Deposits [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value, Cash equivalents	146	157
Cash Equivalents | Quoted Prices In Active Markets For Identical Financial Instruments (Level 1) | Money market funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value, Cash equivalents	666	2,100
Other Current Assets and Other Assets [Domain] | Significant Other Observable Inputs (Level 2) | Foreign currency derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value, Foreign currency derivatives, assets	28	33
Other assets | Quoted Prices In Active Markets For Identical Financial Instruments (Level 1) | Deferred compensation plan assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value, Deferred compensation plan assets	21	18
Accrued and Other Current Liabilities and Other Liabilities | Significant Other Observable Inputs (Level 2) | Foreign currency derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value, Foreign currency derivatives, liabilities	37	40
Other liabilities | Quoted Prices In Active Markets For Identical Financial Instruments (Level 1) | Deferred Compensation Plan Liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value, Deferred compensation plan assets	22	19
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Total assets at fair value	1,742	3,490
Total liabilities at fair value	59	59
Fair Value | Short-term investments | U.S. agency securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value, Available-for-sale of securities	3	3
Fair Value | Short-term investments | Debt Security, Government, Non-US [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value, Available-for-sale of securities	63	67
Fair Value | Short-term investments | Asset-backed Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Asset-backed securities	117	112
Fair Value | Short-term investments | Certificates of Deposit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value, Available-for-sale of securities	37	41
Fair Value | Short-Term Investments And Cash Equivalents | Corporate bonds
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value, Available-for-sale of securities	335	380
Fair Value | Short-Term Investments And Cash Equivalents | U.S. Treasury securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value, Available-for-sale of securities	200	437
Fair Value | Short-Term Investments And Cash Equivalents | Commercial paper
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value, Available-for-sale of securities	126	142
Fair Value | Cash Equivalents | Bank Time Deposits [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value, Cash equivalents	146	157
Fair Value | Cash Equivalents | Money market funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value, Cash equivalents	666	2,100
Fair Value | Other Current Assets and Other Assets [Domain] | Foreign currency derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value, Foreign currency derivatives, assets	28	33
Fair Value | Other assets | Deferred compensation plan assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value, Deferred compensation plan assets	21	18
Fair Value | Accrued and Other Current Liabilities and Other Liabilities | Foreign currency derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value, Foreign currency derivatives, liabilities	37	40
Fair Value | Other liabilities | Deferred Compensation Plan Liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value, Deferred compensation plan assets	$ 22	$ 19