Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	12 Months Ended
	Jul. 28, 2012 Year	Jul. 30, 2011	Jul. 31, 2010
Summary Of Significant Accounting Policies [Line Items]
Average lease term	4 years
Loan receivables, term	3 years
Depreciation And Amortization Expense Property And Equipment	$ 1,100,000,000	$ 1,100,000,000	$ 1,000,000,000
Purchased intangible assets, estimated useful lives, years, minimum	2
Purchased intangible assets, estimated useful lives, years, maximum	7
Advertising costs	$ 218,000,000	$ 325,000,000	$ 290,000,000
Risk Level, Low
Summary Of Significant Accounting Policies [Line Items]
Internal credit risk rating	1
Risk Level, High
Summary Of Significant Accounting Policies [Line Items]
Internal credit risk rating	10
Minimum
Summary Of Significant Accounting Policies [Line Items]
Financed service contracts, term	1 year
Revolving short-term financing, payment terms range (in days)	60
Period for recognition of technical support services revenue, in years	1
Maximum
Summary Of Significant Accounting Policies [Line Items]
Financed service contracts, term	3 years
Revolving short-term financing, payment terms range (in days)	90
Period for recognition of technical support services revenue, in years	3