Summary of Significant Accounting Policies (Additional Information) (Details) $ in Millions	12 Months Ended
	Jul. 29, 2017 USD ($) rating	Jul. 30, 2016 USD ($)	Jul. 25, 2015 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	$ 1,000	$ 1,100
Advertising costs | $	209	186	$ 202
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	$ 1,100
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