Financing Receivables and Operating Leases (Schedule Of Financing Receivables Categorized By Internal Credit Risk Rating) (Details) - USD ($) $ in Millions	Jan. 28, 2017	Jul. 30, 2016
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	$ 9,347	$ 8,603
1 to 4
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	5,520	4,766
5 to 6
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	3,498	3,532
7 and Higher
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	329	305
Total
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	9,347	8,603
Lease Receivables | 1 to 4
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	1,505	1,703
Lease Receivables | 5 to 6
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	1,209	1,294
Lease Receivables | 7 and Higher
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	99	101
Lease Receivables | Total
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	2,813	3,098
Loan Receivables | 1 to 4
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	1,259	986
Loan Receivables | 5 to 6
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	934	967
Loan Receivables | 7 and Higher
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	176	182
Loan Receivables | Total
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	2,369	2,135
Financed Service Contracts and Other | 1 to 4
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	2,756	2,077
Financed Service Contracts and Other | 5 to 6
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	1,355	1,271
Financed Service Contracts and Other | 7 and Higher
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	54	22
Financed Service Contracts and Other | Total
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	$ 4,165	$ 3,370