Revenue - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 27, 2019	Jul. 29, 2018	Jul. 28, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Payment terms	30 days
Accounts receivable, net	$ 5,491	$ 5,450	$ 5,554
Total deferred revenue	18,467		19,685
Revenue recognized	9,600
Remaining performance obligation	25,300
Total deferred sales commissions	750
Amortization of sales commissions, expense	471
Unbilled Contract Revenue
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Remaining performance obligation	6,800
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
Software and Service Agreements
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total contract assets	$ 860		$ 122