Financing Receivables and Operating Leases (Schedule of Financing Receivables Categorized by Internal Credit Risk Rating) (Details) - USD ($) $ in Millions	Jul. 28, 2018	Jul. 29, 2017
Financing Receivable, Recorded Investment [Line Items]
Gross receivables	$ 9,872	$ 9,716
1 to 4
Financing Receivable, Recorded Investment [Line Items]
Gross receivables	5,946	5,866
5 to 6
Financing Receivable, Recorded Investment [Line Items]
Gross receivables	3,786	3,599
7 and Higher
Financing Receivable, Recorded Investment [Line Items]
Gross receivables	140	251
Total
Financing Receivable, Recorded Investment [Line Items]
Gross receivables	9,872	9,716
Lease receivables
Financing Receivable, Recorded Investment [Line Items]
Gross receivables	2,547	2,639
Lease receivables | 1 to 4
Financing Receivable, Recorded Investment [Line Items]
Gross receivables	1,294	1,408
Lease receivables | 5 to 6
Financing Receivable, Recorded Investment [Line Items]
Gross receivables	1,199	1,181
Lease receivables | 7 and Higher
Financing Receivable, Recorded Investment [Line Items]
Gross receivables	54	50
Lease receivables | Total
Financing Receivable, Recorded Investment [Line Items]
Gross receivables	2,547	2,639
Loan receivables | 1 to 4
Financing Receivable, Recorded Investment [Line Items]
Gross receivables	3,184	2,865
Loan receivables | 5 to 6
Financing Receivable, Recorded Investment [Line Items]
Gross receivables	1,752	1,516
Loan receivables | 7 and Higher
Financing Receivable, Recorded Investment [Line Items]
Gross receivables	63	179
Loan receivables | Total
Financing Receivable, Recorded Investment [Line Items]
Gross receivables	4,999	4,560
Financed service contracts
Financing Receivable, Recorded Investment [Line Items]
Gross receivables	2,326	2,517
Financed service contracts | 1 to 4
Financing Receivable, Recorded Investment [Line Items]
Gross receivables	1,468	1,593
Financed service contracts | 5 to 6
Financing Receivable, Recorded Investment [Line Items]
Gross receivables	835	902
Financed service contracts | 7 and Higher
Financing Receivable, Recorded Investment [Line Items]
Gross receivables	23	22
Financed service contracts | Total
Financing Receivable, Recorded Investment [Line Items]
Gross receivables	$ 2,326	$ 2,517