Financing Receivables and Operating Leases (Schedule of Aging Analysis of Financing Receivables) (Details) - USD ($) $ in Millions	Jan. 26, 2019	Jul. 28, 2018
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 1,004	$ 1,185
Current	8,665	8,687
Total	9,669	9,872
Nonaccrual Financing Receivables	33	42
Impaired Financing Receivables	33	42
Past due 31-60 days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	226	314
Past due 61-90 days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	111	160
Past due 91 or above days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	667	711
Lease Receivables
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	265	254
Current	2,080	2,293
Total	2,345	2,547
Nonaccrual Financing Receivables	3	9
Impaired Financing Receivables	3	9
Lease Receivables | Past due 31-60 days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	79	72
Lease Receivables | Past due 61-90 days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	34	27
Lease Receivables | Past due 91 or above days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	152	155
Loan Receivables
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	347	411
Current	4,579	4,588
Total	4,926	4,999
Nonaccrual Financing Receivables	28	30
Impaired Financing Receivables	28	30
Loan Receivables | Past due 31-60 days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	73	104
Loan Receivables | Past due 61-90 days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	39	55
Loan Receivables | Past due 91 or above days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	235	252
Financed Service Contracts
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	392	520
Current	2,006	1,806
Total	2,398	2,326
Nonaccrual Financing Receivables	2	3
Impaired Financing Receivables	2	3
Financed Service Contracts | Past due 31-60 days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	74	138
Financed Service Contracts | Past due 61-90 days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	38	78
Financed Service Contracts | Past due 91 or above days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 280	$ 304