Financing Receivables and Operating Leases (Schedule of Financing Receivables Categorized by Internal Credit Risk Rating) (Details) - USD ($) $ in Millions	Apr. 27, 2019	Jul. 28, 2018
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	$ 9,892	$ 9,872
1 to 4
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	5,773	5,946
5 to 6
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	3,903	3,786
7 and Higher
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	216	140
Total
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	9,892	9,872
Lease Receivables | 1 to 4
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	1,235	1,294
Lease Receivables | 5 to 6
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	1,029	1,199
Lease Receivables | 7 and Higher
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	39	54
Lease Receivables | Total
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	2,303	2,547
Loan Receivables | 1 to 4
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	3,187	3,184
Loan Receivables | 5 to 6
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	1,890	1,752
Loan Receivables | 7 and Higher
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	163	63
Loan Receivables | Total
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	5,240	4,999
Financed Service Contracts | 1 to 4
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	1,351	1,468
Financed Service Contracts | 5 to 6
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	984	835
Financed Service Contracts | 7 and Higher
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	14	23
Financed Service Contracts | Total
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	$ 2,349	$ 2,326