Income Taxes - Components of deferred tax assets and liabilities (Details) - USD ($) $ in Millions	Jul. 31, 2019	Jul. 31, 2018
Deferred tax assets:
Accruals and reserves not currently deductible	$ 13	$ 12
Deferred rent	8	8
Accrued and deferred compensation	48	41
Loss and tax credit carryforwards	117	97
Share-based compensation	47	49
Other, net	3	3
Total gross deferred tax assets	236	210
Valuation allowance	(107)	(93)
Total deferred tax assets	129	117
Deferred tax liabilities:
Deferred revenue	66	91
Intangible assets	71	65
Property and equipment	20	19
Other, net	8	8
Total deferred tax liabilities	165	183
Total deferred tax liabilities	(36)	(66)
Deferred Tax Assets, Net [Abstract]
Long-term deferred income taxes included in other assets	1	2
Long-term deferred income tax liabilities	$ (37)	$ (68)