Income Taxes - Income Tax Contingency (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Income Tax Contingency [Line Items]
Other foreign earnings not indefinitely reinvested				$ 522
Distribution of accumulated foreign earnings	$ 550
Liability For Uncertain Tax Positions [Abstract]
Tax	253	$ 165	$ 219	354	$ 253	$ 165
Interest				46	45	41
Penalties				22	21	25
Offset to receivable				(18)	(24)
Net of tax attributes				(10)	(12)
Total				394	283
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of fiscal year	253	165	219
Gross increases related to prior year tax positions	60	74	4
Gross decreases related to prior year tax positions	(30)	(9)	(27)
Gross increases related to current year tax positions	102	15	0
Settlements and statute of limitation expirations	(36)	(7)	(23)
Acquisitions	6	18	0
Foreign exchange and others	(1)	(3)	(8)
Balance at end of fiscal year	354	253	165
Liability for uncertain tax positions that if recognized would affect the effective tax rate				316	210	138
Interest Accrued Related to Uncertain Tax Positions and Penalties [Abstract]
Unrecognized Tax Benefits, Interest on Income Taxes Expense	1	5	2
Unrecognized Tax Benefits Interest On Income Taxes Expense Net Of Tax	(1)	3	1
Unrecognized Tax Benefits, Income Tax Penalties Expense	1	$ (3)	$ (1)
Unrecognized Tax Benefits, Interest on Income Taxes Accrued				46	45	41
Unrecognized Tax Benefits Interest On Income Taxes Accrued Net Of Tax				39	40	36
Unrecognized Tax Benefits, Income Tax Penalties Accrued				22	$ 21	$ 25
Potential federal and state cost from tax examinations	$ 405
Settlement with Taxing Authority
Interest Accrued Related to Uncertain Tax Positions and Penalties [Abstract]
Reasonably possible reduction in liability for uncertain tax positions in next twelve months				$ 52