Accounts Receivable (Details) - USD ($) $ in Millions	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Receivables [Abstract]
Trade accounts receivable	$ 971	$ 884
Other accounts receivable	102	75
Accounts receivable — third parties	1,073	959
Allowance for doubtful accounts — third parties	(6)	(3)	$ (3)	$ (4)
Accounts receivable, net — third parties	1,067	956
Accounts receivable, net — related parties	$ 60	$ 59