Summary of Significant Accounting Policies (Additional Information) (Details) $ in Millions	3 Months Ended	12 Months Ended
	Apr. 28, 2018 USD ($)	Jul. 28, 2018 USD ($) rating	Jul. 29, 2017 USD ($)	Jul. 30, 2016 USD ($)	Oct. 27, 2018 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Average lease term		4 years
Investment credit risk ratings lowest range (credit risk rating) | rating		1
Investment credit risk ratings range highest (credit risk rating) | rating		10
Rating at or higher when receivables deemed impaired (credit risk rating) | rating		8
Threshold for past due receivables		31 days
Threshold for not accruing interest		90 days
Depreciation and amortization expenses		$ 1,100	$ 1,100	$ 1,000
Advertising costs		166	209	$ 186
Effect of adoption of accounting standards		9
Increase to retained earnings		1,233	20,838
Reduction of deferred revenue		(19,685)	(18,494)
Increase in net deferred tax assets		3,219	4,239
Forecast | Accounting Standards Update 2016-01
Summary Of Significant Accounting Policies [Line Items]
Increase to retained earnings					$ 300
Forecast | Accounting Standards Update 2016-16
Summary Of Significant Accounting Policies [Line Items]
Increase to retained earnings					1,400
Increase in net deferred tax assets					1,300
Forecast | Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09
Summary Of Significant Accounting Policies [Line Items]
Increase to retained earnings					2,300
Reduction of deferred revenue					2,800
Accumulated Other Comprehensive Income (Loss)
Summary Of Significant Accounting Policies [Line Items]
Effect of adoption of accounting standards	$ 45	45
Estimated accruals for rebates, cooperative marketing and other programs with distributors and partners
Summary Of Significant Accounting Policies [Line Items]
Other current liabilities		$ 1,000	$ 1,000
Recurring software and subscription offers | Forecast | Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09
Summary Of Significant Accounting Policies [Line Items]
Reduction of deferred revenue					1,300
Two-tier distribution | Forecast | Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09
Summary Of Significant Accounting Policies [Line Items]
Reduction of deferred revenue					$ 600
Maximum
Summary Of Significant Accounting Policies [Line Items]
Loan receivables term		3 years
Financed service contracts term		3 years
Channel partners revolving short-term financing payment term		90 days
End user lease and loan term		3 years
Maximum | Technical support services
Summary Of Significant Accounting Policies [Line Items]
Deferred revenue recognition period		3 years
Minimum
Summary Of Significant Accounting Policies [Line Items]
Financed service contracts term		1 year
Channel partners revolving short-term financing payment term		60 days
Minimum | Technical support services
Summary Of Significant Accounting Policies [Line Items]
Deferred revenue recognition period		1 year