Financial Instruments (Schedule Of The Fair Value Of Derivative Instruments) (Details) (USD $) In Millions, unless otherwise specified	Jan. 29, 2012	Jul. 31, 2011
Derivatives, Fair Value [Line Items]
Asset Derivatives	$ 46	$ 37
Liability Derivatives	101	143
Derivatives Designated As Hedges [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	24	33
Liability Derivatives	27	45
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	1	7
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	26	30
Derivatives Designated As Hedges [Member] | Interest Rate Swap [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	10	0
Derivatives Designated As Hedges [Member] | Interest Rate Swap [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	13	33
Derivatives Not Designated As Hedges [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	22	4
Liability Derivatives	74	98
Derivatives Not Designated As Hedges [Member] | Foreign Exchange Forward Contracts [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	2	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] | Commodity Derivative Contracts [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	1	3
Derivatives Not Designated As Hedges [Member] | Commodity Derivative Contracts [Member] | Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives	3	2
Derivatives Not Designated As Hedges [Member] | Cross-Currency Swap Contracts [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	9	0
Derivatives Not Designated As Hedges [Member] | Cross-Currency Swap Contracts [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	9	1
Derivatives Not Designated As Hedges [Member] | Cross-Currency Swap Contracts [Member] | Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives	10	17
Derivatives Not Designated As Hedges [Member] | Cross-Currency Swap Contracts [Member] | Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives	58	74
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	$ 3	$ 3