Fair Value (Fair Value, Nonrecurring Measurement) (Details) - Level 3 - USD ($) $ in Millions	3 Months Ended
	Oct. 29, 2016	Oct. 24, 2015
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Gains (losses) for assets measured on a nonrecurring basis	$ (89)	$ (17)
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	(47)	(17)
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	$ (42)	$ 0