Financing Receivables and Operating Leases (Schedule of Aging Analysis of Financing Receivables) (Details) - USD ($) $ in Millions	Oct. 27, 2018	Jul. 28, 2018
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 1,294	$ 1,185
Current	8,241	8,687
Total	9,535	9,872
Nonaccrual Financing Receivables	37	42
Impaired Financing Receivables	37	42
Past due 31-60 days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	304	314
Past due 61-90 days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	259	160
Past due 91 or above days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	731	711
Lease Receivables
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	227	254
Current	2,144	2,293
Total	2,371	2,547
Nonaccrual Financing Receivables	5	9
Impaired Financing Receivables	5	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	27	27
Lease Receivables | Past due 91 or above days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	121	155
Loan Receivables
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	556	411
Current	4,368	4,588
Total	4,924	4,999
Nonaccrual Financing Receivables	29	30
Impaired Financing Receivables	29	30
Loan Receivables | Past due 31-60 days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	123	104
Loan Receivables | Past due 61-90 days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	85	55
Loan Receivables | Past due 91 or above days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	348	252
Financed Service Contracts
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	511	520
Current	1,729	1,806
Total	2,240	2,326
Nonaccrual Financing Receivables	3	3
Impaired Financing Receivables	3	3
Financed Service Contracts | Past due 31-60 days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	102	138
Financed Service Contracts | Past due 61-90 days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	147	78
Financed Service Contracts | Past due 91 or above days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 262	$ 304