Fair Value (Fair Value On Nonrecurring Basis) (Details) - Fair Value, Measurements, Nonrecurring - Level 3 - USD ($) $ in Millions	12 Months Ended
	Jul. 28, 2018	Jul. 29, 2017	Jul. 30, 2016
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Total gains (losses) for nonrecurring measurements	$ (43)	$ (254)	$ (141)
Investments in privately held companies (impaired)
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Total gains (losses) for nonrecurring measurements	(56)	(175)	(57)
Purchased intangible assets (impaired)
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Total gains (losses) for nonrecurring measurements	(1)	(47)	(74)
Property held for sale - land and buildings
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Total gains (losses) for nonrecurring measurements	20	(30)	0
Gains (losses) on assets no longer held at end of fiscal year
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Total gains (losses) for nonrecurring measurements	$ (6)	$ (2)	$ (10)