Receivables - Allowance for Doubtful Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 60	$ 40	$ 26
Additions charged to costs and expenses	23	19	45
Deductions	(4)	(4)	(37)
Other	(5)	5	6
Ending balance	$ 74	$ 60	$ 40