Income Taxes - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Jul. 31, 2019	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2017
Operating Loss Carryforwards [Line Items]
Excess tax benefits related to stock-based compensation		$ 120	$ 100	$ 72
Federal statutory income tax rate		21.00%	26.90%	35.00%
Provisional benefit related to re-measurement of certain deferred tax balances			$ 29
Capital loss on subsidiary reorganization	$ 35	$ 0	35	$ 0
Total net deferred tax assets, net of valuation allowance	129	129	117
Valuation allowance	107	107	93
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Excess tax benefits related to stock-based compensation		14	6	3
Operating loss carryforwards	133	133
Total net deferred tax assets, net of valuation allowance	9	9
Valuation allowance	7	7
Domestic Country
Operating Loss Carryforwards [Line Items]
Excess tax benefits related to stock-based compensation		(106)	$ (94)	$ (69)
Operating loss carryforwards	42	42
Foreign Tax Authority | Inland Revenue, Singapore (IRAS)
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	62	62
Foreign Tax Authority | Secretariat of the Federal Revenue Bureau of Brazil
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	34	34
Research Tax Credit Carryforward | State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Deferred tax assets, tax credit carryforwards	$ 129	$ 129