Consolidated Statements of Other Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Net income	$ 1,019	$ 1,043	$ 967
Other comprehensive income (loss), net of tax:
Net gains (losses) on available-for-sale securities	7	(5)	(4)
Net gains (losses) on derivative instruments	88	(121)	18
Foreign currency translation adjustments	(21)	18	(17)
Total other comprehensive income (loss), net of tax	74	(108)	(3)
Total comprehensive income (loss)	$ 1,093	$ 935	$ 964