Fair Value (Fair Value, Nonrecurring Measurement) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jan. 23, 2016	Jan. 24, 2015	Jan. 23, 2016	Jan. 24, 2015
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Gains (losses) for assets measured on a nonrecurring basis	$ (76)	$ (58)	$ (93)	$ (59)
Level 3 | Investments In Privately Held Companies | Other Income (loss), net
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Gains (losses) for assets measured on a nonrecurring basis	(39)	(2)	(56)	(3)
Level 3 | Purchased Intangible Assets [Member] | Cost of Sales and Operating Expenses
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Gains (losses) for assets measured on a nonrecurring basis	$ (37)	$ (56)	$ (37)	$ (56)