Summary of Significant Accounting Policies (Additional Information) (Details) (USD $)	12 Months Ended
	Jul. 26, 2014 Rating	Jul. 27, 2013	Jul. 28, 2012
Summary Of Significant Accounting Policies [Line Items]
Average lease term (in years)	4 years
Loan receivables term (in years)	3 years
Investment Credit Risk Ratings Range Lowest (credit risk rating)	1
Investment Credit Risk Ratings Range Highest (credit risk rating)	10
Rating at or higher when receivables deemed impaired (credit risk rating)	8
Threshold for past due receivables (in days)	31 days
Threshold for not accruing interest (in days)	90 days
End User Lease And Loan Term	3 years
Depreciation, Depletion and Amortization	$ 1,200,000,000	$ 1,200,000,000	$ 1,100,000,000
Advertising costs	196,000,000	218,000,000	218,000,000
Minimum
Summary Of Significant Accounting Policies [Line Items]
Financed service contracts term (in years)	1 year
Channel partners revolving short-term financing payment term	60 days
Maximum
Summary Of Significant Accounting Policies [Line Items]
Loan receivables term (in years)	3 years
Financed service contracts term (in years)	3 years
Channel partners revolving short-term financing payment term	90 days
End User Lease And Loan Term	3 years
Technical support services [Member] | Minimum
Summary Of Significant Accounting Policies [Line Items]
Deferred revenue recognition period	1 year
Technical support services [Member] | Maximum
Summary Of Significant Accounting Policies [Line Items]
Deferred revenue recognition period	3 years
Estimated accruals for cooperative marketing and other programs with distributors and partners [Member]
Summary Of Significant Accounting Policies [Line Items]
Other Accrued Liabilities, Current	$ 1,300,000,000	$ 1,100,000,000