Financing Receivables and Operating Leases (Schedule of Aging Analysis of Financing Receivables) (Details) - USD ($) $ in Millions	Jul. 28, 2018	Jul. 29, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 1,185	$ 1,733
Current	8,687	7,983
Total	9,872	9,716
Nonaccrual Financing Receivables	42	75
Impaired Financing Receivables	42	59
Past due 31 - 60 days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	314	550
Past due 61 -90 days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	160	185
Past due 91 or above days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	711	998
Lease receivables
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	254	436
Current	2,293	2,203
Total	2,547	2,639
Nonaccrual Financing Receivables	9	14
Impaired Financing Receivables	9	14
Lease receivables | Past due 31 - 60 days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	72	160
Lease receivables | Past due 61 -90 days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	27	60
Lease receivables | Past due 91 or above days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	155	216
Loan receivables
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	411	537
Current	4,588	4,023
Total	4,999	4,560
Nonaccrual Financing Receivables	30	43
Impaired Financing Receivables	30	43
Loan receivables | Past due 31 - 60 days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	104	230
Loan receivables | Past due 61 -90 days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	55	48
Loan receivables | Past due 91 or above days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	252	259
Financed service contracts
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	520	760
Current	1,806	1,757
Total	2,326	2,517
Nonaccrual Financing Receivables	3	18
Impaired Financing Receivables	3	2
Financed service contracts | Past due 31 - 60 days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	138	160
Financed service contracts | Past due 61 -90 days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	78	77
Financed service contracts | Past due 91 or above days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 304	$ 523