Financial Instruments (Fair Value Of Short-Term Investments) (Details) - USD ($) $ in Millions	Dec. 31, 2022	Mar. 31, 2022
Financial Instruments
Fair Value	$ 351	$ 330	[1]
Short-term investments
Financial Instruments
Debt Securities, Available-for-sale, Amortized Cost	353	332
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(2)	(2)
Fair Value	351	330
Short-term investments | Corporate bonds
Financial Instruments
Debt Securities, Available-for-sale, Amortized Cost	136	117
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(1)	(1)
Fair Value	135	116
Short-term investments | U.S. Treasury securities
Financial Instruments
Debt Securities, Available-for-sale, Amortized Cost	85	103
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(1)	(1)
Fair Value	84	102
Short-term investments | U.S. agency securities
Financial Instruments
Debt Securities, Available-for-sale, Amortized Cost	8	0
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	8	0
Short-term investments | Commercial paper
Financial Instruments
Debt Securities, Available-for-sale, Amortized Cost	50	39
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	50	39
Short-term investments | Debt Security, Government, Non-US [Member]
Financial Instruments
Debt Securities, Available-for-sale, Amortized Cost	15	17
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	15	17
Short-term investments | Asset-backed Securities [Member]
Financial Instruments
Debt Securities, Available-for-sale, Amortized Cost	40	38
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	40	38
Short-term investments | Certificates of Deposit [Member]
Financial Instruments
Debt Securities, Available-for-sale, Amortized Cost	19	18
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	$ 19	$ 18

[1] Derived from audited Consolidated Financial Statements.