Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
Oct. 31, 2019	Oct. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 57	$ 34
Other comprehensive income (loss), net of income taxes:
Unrealized gain on available-for-sale debt securities	1	0
Foreign currency translation loss	0	(4)
Total other comprehensive income (loss), net	1	(4)
Comprehensive income	$ 58	$ 30

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