Financing Receivables and Operating Leases (Schedule of Financing Receivables Categorized by Internal Credit Risk Rating) (Details) - USD ($) $ in Millions	Jan. 27, 2018	Jul. 29, 2017
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	$ 9,942	$ 9,716
1 to 4
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	5,948	5,866
5 to 6
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	3,855	3,599
7 and Higher
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	139	251
Total
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	9,942	9,716
Lease Receivables | 1 to 4
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	1,322	1,408
Lease Receivables | 5 to 6
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	1,244	1,181
Lease Receivables | 7 and Higher
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	51	50
Lease Receivables | Total
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	2,617	2,639
Loan Receivables | 1 to 4
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	3,054	2,865
Loan Receivables | 5 to 6
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	1,716	1,516
Loan Receivables | 7 and Higher
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	76	179
Loan Receivables | Total
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	4,846	4,560
Financed Service Contracts | 1 to 4
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	1,572	1,593
Financed Service Contracts | 5 to 6
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	895	902
Financed Service Contracts | 7 and Higher
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	12	22
Financed Service Contracts | Total
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	$ 2,479	$ 2,517