Financial Instruments (Schedule Of The Fair Value Of Derivative Instruments) (Details) (USD $) In Millions, unless otherwise specified	Jan. 27, 2013	Jul. 29, 2012
Derivatives, Fair Value [Line Items]
Asset Derivatives	$ 25	$ 45
Liability Derivatives	84	83
Cash Flow Hedging [Member] | Cross-Currency Swap Contracts [Member] | Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives	24	0
Cash Flow Hedging [Member] | Cross-Currency Swap Contracts [Member] | Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives	0	25
Cash Flow Hedging [Member] | Foreign Exchange Forward Contracts [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	0	1
Cash Flow Hedging [Member] | Foreign Exchange Forward Contracts [Member] | Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives	1	0
Cash Flow Hedging [Member] | Interest Rate Swap [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	0	1
Cash Flow Hedging [Member] | Interest Rate Swap [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	9	1
Fair Value Hedging [Member] | Interest Rate Swap [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	6	4
Fair Value Hedging [Member] | Interest Rate Swap [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	0	9
Derivatives Designated As Hedges [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	15	16
Liability Derivatives	25	25
Derivatives Not Designated As Hedges [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	10	29
Liability Derivatives	59	58
Derivatives Not Designated As Hedges [Member] | Commodity Derivative Contracts [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	5	8
Derivatives Not Designated As Hedges [Member] | Commodity Derivative Contracts [Member] | Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives	3	4
Derivatives Not Designated As Hedges [Member] | Cross-Currency Swap Contracts [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	2	19
Derivatives Not Designated As Hedges [Member] | Cross-Currency Swap Contracts [Member] | Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives	53	25
Derivatives Not Designated As Hedges [Member] | Cross-Currency Swap Contracts [Member] | Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives	3	29
Derivatives Not Designated As Hedges [Member] | Foreign Exchange Forward Contracts [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	1	1
Derivatives Not Designated As Hedges [Member] | Deferred Compensation Derivative Contracts [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	$ 2	$ 1