Financing Receivables And Guarantees (Schedule Of Financing Receivables) (Detail) (USD $) In Millions, unless otherwise specified	Jan. 26, 2013	Jul. 28, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes, Loans and Financing Receivable, Net, Noncurrent	$ 3,837	$ 3,585
Financing Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Capital Leases, Future Minimum Payments Receivable	8,365	7,876
Unearned income	(273)	(250)
Financing Receivable, Allowance for Credit Losses	(361)	(380)
Financing Receivable, Recorded Investment, Current	3,894	3,661
Notes, Loans and Financing Receivable, Net, Noncurrent	3,837	3,585
Financing Receivable	7,731	7,246
Lease Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Capital Leases, Future Minimum Payments Receivable	3,717	3,429
Unearned income	(273)	(250)
Financing Receivable, Allowance for Credit Losses	(247)	(247)
Financing Receivable, Recorded Investment, Current	1,349	1,200
Notes, Loans and Financing Receivable, Net, Noncurrent	1,848	1,732
Financing Receivable	3,197	2,932
Loan Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Capital Leases, Future Minimum Payments Receivable	1,785	1,796
Unearned income	0	0
Financing Receivable, Allowance for Credit Losses	(101)	(122)
Financing Receivable, Recorded Investment, Current	960	968
Notes, Loans and Financing Receivable, Net, Noncurrent	724	706
Financing Receivable	1,684	1,674
Financed Service Contracts And Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Capital Leases, Future Minimum Payments Receivable	2,863	2,651
Unearned income	0	0
Financing Receivable, Allowance for Credit Losses	(13)	(11)
Financing Receivable, Recorded Investment, Current	1,585	1,493
Notes, Loans and Financing Receivable, Net, Noncurrent	1,265	1,147
Financing Receivable	$ 2,850	$ 2,640