Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2018	Apr. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 1,200	$ 964	$ 1,162	$ 947
Other comprehensive income (loss), net of income taxes:
Unrealized gain (loss) on available-for-sale debt securities	(1)	0	(2)	(1)
Foreign currency translation gain (loss)	(9)	(2)	(6)	(3)
Total other comprehensive income (loss), net	(10)	(2)	(8)	(4)
Comprehensive income	$ 1,190	$ 962	$ 1,154	$ 943