Fair Value - Additional Information (Detail) (USD $)	Jan. 25, 2014	Jul. 27, 2013
Other Fair Value Disclosures [Line Items]
Carrying Value, Cost Method Investments	$ 234,000,000	$ 242,000,000
Long-term Debt, carrying value	16,137,000,000	16,201,000,000
Fair Value, Inputs, Level 3 [Member]
Other Fair Value Disclosures [Line Items]
Loan Receivables, Financed Service Contracts And Others, Carrying Value	1,800,000,000	2,100,000,000
Fair Value, Inputs, Level 2 [Member]
Other Fair Value Disclosures [Line Items]
Long-term Debt, Fair Value	17,300,000,000	17,600,000,000
Long-term Debt, carrying value	$ 16,100,000,000	$ 16,200,000,000