Financing Receivables and Operating Leases (Schedule Of Financing Receivables Categorized By Internal Credit Risk Rating) (Details) - USD ($) $ in Millions	Apr. 30, 2016	Jul. 25, 2015
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	$ 8,794	$ 8,507
1 to 4
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	4,884	4,609
5 to 6
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	3,597	3,554
7 and Higher
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	313	344
Total
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	8,794	8,507
Lease Receivables | 1 to 4
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	1,677	1,688
Lease Receivables | 5 to 6
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	1,276	1,342
Lease Receivables | 7 and Higher
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	114	141
Lease Receivables | Total
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	3,067	3,171
Loan Receivables | 1 to 4
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	991	788
Loan Receivables | 5 to 6
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	1,079	823
Loan Receivables | 7 and Higher
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	153	152
Loan Receivables | Total
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	2,223	1,763
Financed Service Contracts and Other | 1 to 4
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	2,216	2,133
Financed Service Contracts and Other | 5 to 6
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	1,242	1,389
Financed Service Contracts and Other | 7 and Higher
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	46	51
Financed Service Contracts and Other | Total
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	$ 3,504	$ 3,573