Financial Instruments (Schedule Of The Fair Value Of Derivative Instruments) (Details) (USD $) In Millions, unless otherwise specified	Jul. 29, 2012	Jul. 31, 2011
Derivatives, Fair Value [Line Items]
Asset Derivatives	$ 45	$ 37
Liability Derivatives	83	143
Derivatives Designated As Hedges [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	16	33
Liability Derivatives	25	45
Derivatives Designated As Hedges [Member] | Cross-Currency Swap Contracts [Member] | Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives	0	8
Derivatives Designated As Hedges [Member] | Cross-Currency Swap Contracts [Member] | Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives	25	30
Derivatives Designated As Hedges [Member] | Foreign Exchange Forward Contracts [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	1	0
Derivatives Designated As Hedges [Member] | Foreign Exchange Forward Contracts [Member] | Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives	0	7
Cash Flow Hedging [Member] | Interest Rate Swap [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	1	0
Cash Flow Hedging [Member] | Interest Rate Swap [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	1	0
Fair Value Hedging [Member] | Interest Rate Swap [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	4	0
Fair Value Hedging [Member] | Interest Rate Swap [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	9	33
Derivatives Not Designated As Hedges [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	29	4
Liability Derivatives	58	98
Derivatives Not Designated As Hedges [Member] | Commodity Derivative Contracts [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	8	3
Derivatives Not Designated As Hedges [Member] | Commodity Derivative Contracts [Member] | Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives	4	2
Derivatives Not Designated As Hedges [Member] | Cross-Currency Swap Contracts [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	19	0
Derivatives Not Designated As Hedges [Member] | Cross-Currency Swap Contracts [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	0	1
Derivatives Not Designated As Hedges [Member] | Cross-Currency Swap Contracts [Member] | Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives	25	17
Derivatives Not Designated As Hedges [Member] | Cross-Currency Swap Contracts [Member] | Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives	29	74
Derivatives Not Designated As Hedges [Member] | Foreign Exchange Forward Contracts [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	1	0
Derivatives Not Designated As Hedges [Member] | Foreign Exchange Forward Contracts [Member] | Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives	0	2
Derivatives Not Designated As Hedges [Member] | Deferred Compensation Derivative Contracts [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	1	0
Derivatives Not Designated As Hedges [Member] | Deferred Compensation Derivative Contracts [Member] | Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives	$ 0	$ 3