Fair Value (Fair Value, Nonrecurring Measurement) (Details) - Level 3 - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Apr. 30, 2016	Apr. 25, 2015	Apr. 30, 2016	Apr. 25, 2015
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Gains (losses) for assets measured on a nonrecurring basis	$ (14)	$ (23)	$ (107)	$ (82)
Investments In Privately Held Companies (impaired) | Other Income (loss), net
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Gains (losses) for assets measured on a nonrecurring basis	(7)	(17)	(63)	(20)
Purchased Intangible Assets (impaired) | 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	(7)	(1)	(44)	(57)
Property held for sale- land and buildings (impaired) | General and administrative
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Gains (losses) for assets measured on a nonrecurring basis	$ 0	$ (5)	$ 0	$ (5)