Derivative Instruments (Derivatives Recorded At Fair Value) (Details) (USD $) In Millions, unless otherwise specified	Apr. 26, 2014	Jul. 27, 2013
Derivative [Line Items]
Derivative Asset	$ 148	$ 182
Derivative liabilities	54	171
Designated as Hedging Instrument
Derivative [Line Items]
Derivative Asset	143	180
Derivative liabilities	50	164
Designated as Hedging Instrument | Foreign Currency Derivatives | Other Current Assets
Derivative [Line Items]
Derivative Asset	17	33
Designated as Hedging Instrument | Foreign Currency Derivatives | Other Current Liabilities
Derivative [Line Items]
Derivative liabilities	3	7
Designated as Hedging Instrument | Interest Rate Derivatives | Other Noncurrent Assets
Derivative [Line Items]
Derivative Asset	126	147
Designated as Hedging Instrument | Interest Rate Derivatives | Other Noncurrent Liabilities
Derivative [Line Items]
Derivative liabilities	8	2
Designated as Hedging Instrument | Equity Derivatives | Other Current Assets
Derivative [Line Items]
Derivative Asset	0	0
Designated as Hedging Instrument | Equity Derivatives | Other Current Liabilities
Derivative [Line Items]
Derivative liabilities	39	155
Derivatives Not Designated As Hedging Instruments
Derivative [Line Items]
Derivative Asset	5	2
Derivative liabilities	4	7
Derivatives Not Designated As Hedging Instruments | Foreign Currency Derivatives | Other Current Assets
Derivative [Line Items]
Derivative Asset	5	2
Derivatives Not Designated As Hedging Instruments | Foreign Currency Derivatives | Other Current Liabilities
Derivative [Line Items]
Derivative liabilities	4	7
Derivatives Not Designated As Hedging Instruments | Equity Derivatives | Other Noncurrent Assets
Derivative [Line Items]
Derivative Asset	0	0
Derivatives Not Designated As Hedging Instruments | Equity Derivatives | Other Noncurrent Liabilities
Derivative [Line Items]
Derivative liabilities	$ 0	$ 0