Financing Receivables and Operating Leases (Schedule of Aging Analysis of Financing Receivables) (Details) - USD ($) $ in Millions	Jan. 27, 2018	Jul. 29, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 1,366	$ 1,733
Current	8,576	7,983
Total	9,942	9,716
Nonaccrual Financing Receivables	66	75
Impaired Financing Receivables	66	59
Past due 31-60 days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	218	550
Past due 61-90 days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	305	185
Past due 91 or above days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	843	998
Lease Receivables
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	472	436
Current	2,145	2,203
Total	2,617	2,639
Nonaccrual Financing Receivables	19	14
Impaired Financing Receivables	19	14
Lease Receivables | Past due 31-60 days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	98	160
Lease Receivables | Past due 61-90 days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	96	60
Lease Receivables | Past due 91 or above days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	278	216
Loan Receivables
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	341	537
Current	4,505	4,023
Total	4,846	4,560
Nonaccrual Financing Receivables	45	43
Impaired Financing Receivables	45	43
Loan Receivables | Past due 31-60 days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	66	230
Loan Receivables | Past due 61-90 days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	124	48
Loan Receivables | Past due 91 or above days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	151	259
Financed Service Contracts
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	553	760
Current	1,926	1,757
Total	2,479	2,517
Nonaccrual Financing Receivables	2	18
Impaired Financing Receivables	2	2
Financed Service Contracts | Past due 31-60 days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	54	160
Financed Service Contracts | Past due 61-90 days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	85	77
Financed Service Contracts | Past due 91 or above days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 414	$ 523