Investments in Marketable Securities - Schedule of Continuous Unrealized Losses on Available-For-Sale Debt Securities (Details) - USD ($) $ in Millions	Dec. 31, 2023	Mar. 31, 2023
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities, Less than 12 months, Fair value	$ 379	$ 221
Available-for-sale debt securities, 12 months or longer, Fair value	840	810
Available-for-sale debt securities, Total, Fair value	1,219	1,031
Available-for-sale debt securities, Less than 12 months, Unrealized losses	(10)	(7)
Available-for-sale debt securities, 12 months or longer, Unrealized losses	(128)	(133)
Available-for-sale debt securities, Total, Unrealized losses	(138)	(140)
U.S. government and agency obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities, Less than 12 months, Fair value	322	90
Available-for-sale debt securities, 12 months or longer, Fair value	322	304
Available-for-sale debt securities, Total, Fair value	644	394
Available-for-sale debt securities, Less than 12 months, Unrealized losses	(7)	(3)
Available-for-sale debt securities, 12 months or longer, Unrealized losses	(64)	(56)
Available-for-sale debt securities, Total, Unrealized losses	(71)	(59)
Foreign government and agency obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities, Less than 12 months, Fair value	1	0
Available-for-sale debt securities, 12 months or longer, Fair value	9	11
Available-for-sale debt securities, Total, Fair value	10	11
Available-for-sale debt securities, Less than 12 months, Unrealized losses	0	0
Available-for-sale debt securities, 12 months or longer, Unrealized losses	(1)	(2)
Available-for-sale debt securities, Total, Unrealized losses	(1)	(2)
Municipal debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities, Less than 12 months, Fair value	0	0
Available-for-sale debt securities, 12 months or longer, Fair value	0	2
Available-for-sale debt securities, Total, Fair value	2	2
Available-for-sale debt securities, Less than 12 months, Unrealized losses	0	0
Available-for-sale debt securities, 12 months or longer, Unrealized losses	0	(1)
Available-for-sale debt securities, Total, Unrealized losses	0	(1)
Corporate debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities, Less than 12 months, Fair value	18	46
Available-for-sale debt securities, 12 months or longer, Fair value	346	352
Available-for-sale debt securities, Total, Fair value	364	398
Available-for-sale debt securities, Less than 12 months, Unrealized losses	(2)	(2)
Available-for-sale debt securities, 12 months or longer, Unrealized losses	(45)	(57)
Available-for-sale debt securities, Total, Unrealized losses	(47)	(59)
U.S. government agency mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities, Less than 12 months, Fair value	33	38
Available-for-sale debt securities, 12 months or longer, Fair value	42	17
Available-for-sale debt securities, Total, Fair value	75	55
Available-for-sale debt securities, Less than 12 months, Unrealized losses	0	(1)
Available-for-sale debt securities, 12 months or longer, Unrealized losses	(3)	(2)
Available-for-sale debt securities, Total, Unrealized losses	(3)	(3)
Non-agency residential mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities, Less than 12 months, Fair value	0	0
Available-for-sale debt securities, 12 months or longer, Fair value	8	8
Available-for-sale debt securities, Total, Fair value	8	8
Available-for-sale debt securities, Less than 12 months, Unrealized losses	0	0
Available-for-sale debt securities, 12 months or longer, Unrealized losses	(1)	(1)
Available-for-sale debt securities, Total, Unrealized losses	(1)	(1)
Non-agency commercial mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities, Less than 12 months, Fair value	1	0
Available-for-sale debt securities, 12 months or longer, Fair value	53	57
Available-for-sale debt securities, Total, Fair value	54	57
Available-for-sale debt securities, Less than 12 months, Unrealized losses	0	0
Available-for-sale debt securities, 12 months or longer, Unrealized losses	(9)	(8)
Available-for-sale debt securities, Total, Unrealized losses	(9)	(8)
Asset-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities, Less than 12 months, Fair value	4	47
Available-for-sale debt securities, 12 months or longer, Fair value	58	59
Available-for-sale debt securities, Total, Fair value	62	106
Available-for-sale debt securities, Less than 12 months, Unrealized losses	(1)	(1)
Available-for-sale debt securities, 12 months or longer, Unrealized losses	(5)	(6)
Available-for-sale debt securities, Total, Unrealized losses	$ (6)	$ (7)

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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