LEASES - Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$ 152	$ 150
Right‑of‑use assets obtained in exchange for lease liabilities
Operating Lease	$ 159	$ 99