Revenue (Additional Information) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jan. 26, 2019	Jan. 26, 2019	Jul. 29, 2018	Jul. 28, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Payment terms		30 days
Accounts receivable, net	$ 3,745	$ 3,745	$ 5,450	$ 5,554
Total contract assets	5,200	5,200
Total deferred revenue	17,261	17,261		19,685
Revenue recognized	2,600	6,000
Remaining performance obligation	22,500	22,500
Total deferred sales commissions	686	686		644
Amortization of sales commissions, expense	100	212
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	$ 557	$ 557		$ 122