Derivative Instruments (Derivatives Recorded At Fair Value) (Detail) (USD $) In Millions, unless otherwise specified	Jul. 27, 2013	Jul. 28, 2012
Derivative [Line Items]
Derivative assets	$ 182	$ 264
Derivative liabilities	171	42
Derivatives Designated As Hedging Instrument
Derivative [Line Items]
Derivative assets	180	247
Derivative liabilities	164	30
Derivatives Designated As Hedging Instrument | Foreign Currency Derivatives | Other current assets
Derivative [Line Items]
Derivative assets	33	24
Derivatives Designated As Hedging Instrument | Foreign Currency Derivatives | Other Current Liabilities
Derivative [Line Items]
Derivative liabilities	7	26
Derivatives Designated As Hedging Instrument | Interest Rate Derivatives | Other assets
Derivative [Line Items]
Derivative assets	147	223
Derivatives Designated As Hedging Instrument | Interest Rate Derivatives | Other Noncurrent Liabilities [Member]
Derivative [Line Items]
Derivative liabilities	2	0
Derivatives Designated As Hedging Instrument | Equity Derivatives | Other current assets
Derivative [Line Items]
Derivative assets	0	0
Derivatives Designated As Hedging Instrument | Equity Derivatives | Other Current Liabilities
Derivative [Line Items]
Derivative liabilities	155	4
Derivatives Not Designated As Hedging Instruments
Derivative [Line Items]
Derivative assets	2	17
Derivative liabilities	7	12
Derivatives Not Designated As Hedging Instruments | Foreign Currency Derivatives | Other current assets
Derivative [Line Items]
Derivative assets	2	16
Derivatives Not Designated As Hedging Instruments | Foreign Currency Derivatives | Other Current Liabilities
Derivative [Line Items]
Derivative liabilities	7	12
Derivatives Not Designated As Hedging Instruments | Equity Derivatives | Other assets
Derivative [Line Items]
Derivative assets	0	1
Derivatives Not Designated As Hedging Instruments | Equity Derivatives | Other Noncurrent Liabilities [Member]
Derivative [Line Items]
Derivative liabilities	$ 0	$ 0