Derivative Instruments (Derivatives Recorded At Fair Value) (Details) (USD $) In Millions, unless otherwise specified	Oct. 26, 2013	Jul. 27, 2013
Derivative [Line Items]
Derivative assets	$ 224	$ 182
Derivative liabilities	145	171
Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative assets	221	180
Derivative liabilities	132	164
Designated as Hedging Instrument [Member] | Foreign Exchange Contract | Other Current Assets [Member]
Derivative [Line Items]
Derivative assets	57	33
Designated as Hedging Instrument [Member] | Foreign Exchange Contract | Other Current Liabilities [Member]
Derivative [Line Items]
Derivative liabilities	10	7
Designated as Hedging Instrument [Member] | Interest Rate Derivatives [Member] | Other Noncurrent Assets [Member]
Derivative [Line Items]
Derivative assets	164	147
Designated as Hedging Instrument [Member] | Interest Rate Derivatives [Member] | Other Noncurrent Liabilities [Member]
Derivative [Line Items]
Derivative liabilities	0	2
Designated as Hedging Instrument [Member] | Equity Derivatives [Member] | Other Current Assets [Member]
Derivative [Line Items]
Derivative assets	0	0
Designated as Hedging Instrument [Member] | Equity Derivatives [Member] | Other Current Liabilities [Member]
Derivative [Line Items]
Derivative liabilities	122	155
Derivatives Not Designated As Hedging Instruments [Member] | Foreign Exchange Contract | Other Current Assets [Member]
Derivative [Line Items]
Derivative assets	3	2
Derivatives Not Designated As Hedging Instruments [Member] | Foreign Exchange Contract | Other Current Liabilities [Member]
Derivative [Line Items]
Derivative liabilities	$ 13	$ 7