Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jan. 31, 2021	Jan. 31, 2020	Jan. 31, 2021	Jan. 31, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 20	$ 240	$ 218	$ 297
Other comprehensive income (loss), net of income taxes:
Unrealized gain (loss) on available-for-sale debt securities	0	1	(1)	2
Foreign currency translation gain (loss)	12	(1)	10	(1)
Total other comprehensive income, net	12	0	9	1
Comprehensive income	$ 32	$ 240	$ 227	$ 298