Financing Receivables and Operating Leases (Schedule Of Financing Receivables Categorized By Internal Credit Risk Rating) (Details) (USD $) In Millions, unless otherwise specified	Jan. 24, 2015		Jul. 26, 2014	Jan. 25, 2014
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	$ 7,906		$ 8,187
Total financing receivables before allowance for credit loss	8,134	[1]	8,420	8,018	[1]
1 to 4
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	3,996		4,312
5 to 6
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	3,531		3,498
7 and Higher
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	379		377
Total
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	7,906		8,187
Lease Receivables
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	3,163		3,294
Total financing receivables before allowance for credit loss	3,391	[1]		3,551	[1]
Lease Receivables | 1 to 4
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	1,632		1,615
Lease Receivables | 5 to 6
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	1,386		1,538
Lease Receivables | 7 and Higher
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	145		141
Lease Receivables | Total
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	3,163		3,294
Loan Receivables
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	1,674		1,683
Total financing receivables before allowance for credit loss	1,674	[1]		1,660	[1]
Loan Receivables | 1 to 4
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	717		953
Loan Receivables | 5 to 6
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	803		593
Loan Receivables | 7 and Higher
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	154		137
Loan Receivables | Total
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	1,674		1,683
Financed Service Contracts and Other
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	3,069		3,210
Total financing receivables before allowance for credit loss	3,069	[1]		2,807	[1]
Financed Service Contracts and Other | 1 to 4
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	1,647		1,744
Financed Service Contracts and Other | 5 to 6
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	1,342		1,367
Financed Service Contracts and Other | 7 and Higher
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	80		99
Financed Service Contracts and Other | Total
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	$ 3,069		$ 3,210

[1] Total financing receivables before allowance for credit loss.