Fair Value (Fair Value, Nonrecurring Measurement) (Details) (Level 3, USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Apr. 25, 2015	Apr. 26, 2014	Apr. 25, 2015	Apr. 26, 2014
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Gains (losses) for assets measured on a nonrecurring basis	$ (23)us-gaap_AssetImpairmentCharges	$ 0us-gaap_AssetImpairmentCharges	$ (82)us-gaap_AssetImpairmentCharges	$ (10)us-gaap_AssetImpairmentCharges
Assets Held-for-sale [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Gains (losses) for assets measured on a nonrecurring basis	(5)	0	(5)	0
Purchased Intangible Assets \| Cost of Sales and Operating Expenses [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Gains (losses) for assets measured on a nonrecurring basis	(1)	0	(57)	0
Investments In Privately Held Companies [Member] \| Other Nonoperating Income (Expense) [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Gains (losses) for assets measured on a nonrecurring basis	$ (17)	$ 0	$ (20)	$ (10)