Consolidated Statements of Other Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Net income	$ 1,043	$ 967	$ 1,156
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	(5)	(4)	4
Other comprehensive income (loss), net of tax:
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	(121)	18	(7)
Foreign currency translation adjustments	18	(17)	(15)
Total other comprehensive loss, net of tax	(108)	(3)	(18)
Total comprehensive income	$ 935	$ 964	$ 1,138