Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Apr. 30, 2019	Apr. 30, 2018	Apr. 30, 2019	Apr. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 1,378	$ 1,186	$ 1,601	$ 1,367
Other comprehensive income (loss), net of income taxes:
Unrealized gain (loss) on available-for-sale debt securities	1	(1)	2	(2)
Foreign currency translation loss	(3)	(11)	(4)	(8)
Total other comprehensive income (loss), net	(2)	(12)	(2)	(10)
Comprehensive income	$ 1,376	$ 1,174	$ 1,599	$ 1,357