Revenue (Additional Information) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Apr. 27, 2019	Apr. 27, 2019	Jul. 29, 2018	Jul. 28, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Payment terms		30 days
Accounts receivable, net	$ 3,795	$ 3,795	$ 5,450	$ 5,554
Total deferred revenue	17,456	17,456		19,685
Revenue recognized	2,000	8,000
Remaining performance obligation	23,000	23,000
Total deferred sales commissions	705	705		644
Amortization of sales commissions, expense	124	349
Unbilled Contract Revenue
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Remaining performance obligation	5,500	5,500
Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accounts receivable, net			(104)
Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total deferred revenue	2,800	2,800	$ 2,800
Software and Service Agreements
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total contract assets	$ 637	$ 637		$ 122