Financing Receivables and Operating Leases (Schedule of Financing Receivables Categorized by Internal Credit Risk Rating) (Details) - USD ($) $ in Millions	Oct. 27, 2018	Jul. 28, 2018
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	$ 9,535	$ 9,872
1 to 4
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	5,814	5,946
5 to 6
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	3,596	3,786
7 and Higher
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	125	140
Total
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	9,535	9,872
Lease Receivables | 1 to 4
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	1,238	1,294
Lease Receivables | 5 to 6
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	1,084	1,199
Lease Receivables | 7 and Higher
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	49	54
Lease Receivables | Total
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	2,371	2,547
Loan Receivables | 1 to 4
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	3,122	3,184
Loan Receivables | 5 to 6
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	1,744	1,752
Loan Receivables | 7 and Higher
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	58	63
Loan Receivables | Total
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	4,924	4,999
Financed Service Contracts | 1 to 4
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	1,454	1,468
Financed Service Contracts | 5 to 6
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	768	835
Financed Service Contracts | 7 and Higher
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	18	23
Financed Service Contracts | Total
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	$ 2,240	$ 2,326