Financing Receivables And Guarantees (Additional Information) (Detail) (USD $)	3 Months Ended		6 Months Ended
	Jan. 26, 2013	Jan. 28, 2012	Jan. 26, 2013 D	Jan. 28, 2012	Jul. 28, 2012
Financing Receivables And Guarantees [Line Items]
Deferred Service Revenue	$ 13,321,000,000		$ 13,321,000,000		$ 12,880,000,000
Capital Leases, Net Investment in Direct Financing Leases	8,092,000,000		8,092,000,000		7,626,000,000
Risk rating for receivables deemed to be impaired, minimum			8
Financing receivables, amount past due on accrual status	82,000,000		82,000,000		109,000,000
Channel partners revolving short-term financing payment term, minimum (days)			60
Channel partners revolving short-term financing payment term, maximum (days)			90
Volume of channel partner financing	5,800,000,000	5,400,000,000	11,400,000,000	10,700,000,000
Balance of the channel partner financing subject to guarantees	1,400,000,000	1,200,000,000	1,400,000,000	1,200,000,000
End User Lease And Loan Term Maximum			3 years
Third Parties Financing Arrangements With Company Guarantee	55,000,000	60,000,000	99,000,000	95,000,000
Lease Receivables [Member]
Financing Receivables And Guarantees [Line Items]
Average term of lease and loan arrangements, years			4 years
Capital Leases, Net Investment in Direct Financing Leases	3,444,000,000	3,049,000,000	3,444,000,000	3,049,000,000	3,179,000,000
Unbilled Or Current In Greater Than Ninety Days Past Due	179,000,000		179,000,000		139,000,000
Loans Receivable [Member]
Financing Receivables And Guarantees [Line Items]
Term Of Loan Receivable Arrangement			3 years
Capital Leases, Net Investment in Direct Financing Leases	1,785,000,000	1,673,000,000	1,785,000,000	1,673,000,000	1,796,000,000
Unbilled Or Current In Greater Than Ninety Days Past Due	6,000,000		6,000,000		3,000,000
Financed Service Contracts And Other [Member]
Financing Receivables And Guarantees [Line Items]
Revenue recognition range, low end, in years			1 year
Revenue recognition range, high end, in years			3 years
Deferred Service Revenue	1,943,000,000		1,943,000,000		1,838,000,000
Capital Leases, Net Investment in Direct Financing Leases	2,863,000,000	2,666,000,000	2,863,000,000	2,666,000,000	2,651,000,000
Unbilled Or Current In Greater Than Ninety Days Past Due	199,000,000		199,000,000		313,000,000
Credit Loss Allowances and deferred revenue [Member]
Financing Receivables And Guarantees [Line Items]
Financing receivable, allowance for credit loss and deferred revenue	2,429,000,000		2,429,000,000		2,387,000,000
Capital Leases, Net Investment in Direct Financing Leases	$ 8,092,000,000		$ 8,092,000,000		$ 7,626,000,000
Internal Credit Rating [Member]
Financing Receivables And Guarantees [Line Items]
Investment Credit Risk Ratings Range Lowest			1
Investment Credit Risk Ratings Range Highest			4
Financing credit risk rating-noninvestment-lowest			5
Financing credit risk rating-noninvestment-highest			6
Financing credit risk rating-substandard			7