Fair Value (Fair Value, Nonrecurring Measurement) (Details) - Fair Value, Measurements, Nonrecurring - Level 3 - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Apr. 29, 2017	Apr. 30, 2016	Apr. 29, 2017	Apr. 30, 2016
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Gains (losses) for assets measured on a nonrecurring basis	$ (51)	$ (14)	$ (228)	$ (107)
Investments in privately held companies (impaired)
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Gains (losses) for assets measured on a nonrecurring basis	(51)	(7)	(162)	(63)
Purchased intangible assets (impaired)
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Gains (losses) for assets measured on a nonrecurring basis	0	(7)	(42)	(44)
Property held for sale—land and buildings
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Gains (losses) for assets measured on a nonrecurring basis	$ 0	$ 0	$ (24)	$ 0