Financing Receivables and Operating Leases (Schedule of Financing Receivables Categorized by Internal Credit Risk Rating) (Details) - USD ($) $ in Millions	Apr. 28, 2018	Jul. 29, 2017
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	$ 9,879	$ 9,716
1 to 4
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	5,960	5,866
5 to 6
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	3,765	3,599
7 and Higher
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	154	251
Total
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	9,879	9,716
Lease Receivables | 1 to 4
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	1,207	1,408
Lease Receivables | 5 to 6
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	1,248	1,181
Lease Receivables | 7 and Higher
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	63	50
Lease Receivables | Total
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	2,518	2,639
Loan Receivables | 1 to 4
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	3,234	2,865
Loan Receivables | 5 to 6
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	1,654	1,516
Loan Receivables | 7 and Higher
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	75	179
Loan Receivables | Total
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	4,963	4,560
Financed Service Contracts | 1 to 4
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	1,519	1,593
Financed Service Contracts | 5 to 6
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	863	902
Financed Service Contracts | 7 and Higher
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	16	22
Financed Service Contracts | Total
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	$ 2,398	$ 2,517