Financing Receivables and Operating Leases (Additional Information) (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 28, 2018	Jul. 29, 2017
Financing Receivables And Guarantees [Line Items]
Average lease term	4 years
Threshold for past due receivables	31 days
Unbilled or current financing receivables included in greater than 91 days plus past due	$ 503	$ 666
Financing receivable 91 days past due and still accruing	$ 182	$ 315
Maximum
Financing Receivables And Guarantees [Line Items]
Loan receivables term	3 years
Financed service contracts term	3 years
Maximum | Financed Service Contracts
Financing Receivables And Guarantees [Line Items]
Financed service contracts term	3 years
Minimum
Financing Receivables And Guarantees [Line Items]
Financed service contracts term	1 year
Minimum | Financed Service Contracts
Financing Receivables And Guarantees [Line Items]
Financed service contracts term	1 year