Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 1,557	$ 1,329	$ 985
Other comprehensive income (loss), net of income taxes:
Unrealized gain (loss) on available-for-sale debt securities	3	(2)	(1)
Foreign currency translation gain (loss)	(3)	(12)	11
Total other comprehensive income (loss), net	0	(14)	10
Comprehensive income	$ 1,557	$ 1,315	$ 995