Financial Instruments (Narrative) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
Jan. 29, 2012	Jul. 31, 2011
Derivatives, Fair Value [Line Items]
Long-term debt, fair value	$ 2,678	$ 2,603
Long-term debt	2,417	2,427
Cash flow hedge ineffectiveness is immaterial	The ineffective portion and amount excluded from effectiveness testing were not material.
Foreign Exchange Forward Contracts [Member]
Derivatives, Fair Value [Line Items]
Contracts mature within, months	18
Notional amount, foreign currency hedges not designated	838	861
Notional Amount of Foreign Currency Cash Flow Hedge Derivatives	251	287
Foreign Exchange Forward Contracts [Member] \| Minimum [Member]
Derivatives, Fair Value [Line Items]
Derivative maturity year	2012
Foreign Exchange Forward Contracts [Member] \| Maximum [Member]
Derivatives, Fair Value [Line Items]
Derivative maturity year	2015
Deferred Compensation Derivative Contracts [Member]
Derivatives, Fair Value [Line Items]
Notional amount, commodity contracts not designated	68	71
Contracts mature within, months	12
Commodity Derivative Contracts [Member]
Derivatives, Fair Value [Line Items]
Notional amount, commodity contracts	1	6
Notional amount, commodity contracts not designated	61	81
Contracts mature within, months	12
Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Notional amount, fair value interest rate swaps	$ 500	$ 500
Interest Rate Swaps [Member] \| Minimum [Member]
Derivatives, Fair Value [Line Items]
Derivative maturity year	2013
Interest Rate Swaps [Member] \| Maximum [Member]
Derivatives, Fair Value [Line Items]
Derivative maturity year	2014

No authoritative reference available.

No definition available.

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- Definition

A disclosure of an assertion that the amount of cash flow hedge ineffectiveness is immaterial.

+ References

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- Definition

Including current and noncurrent portions, aggregate carrying amount of long-term borrowings as of the balance sheet date. May include notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, which had initial maturities beyond one year or beyond the normal operating cycle, if longer, and after deducting unamortized discount or premiums, if any.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22)

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.16)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 7

-Section 03

-Paragraph 16

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.16)

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 16

-Article 9

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 20, 22

-Article 5

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- Definition

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

+ References

No definition available.

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- Definition

Maximum length of time over which the entity is hedging its exposure to the variability in future cash flows for forecasted transactions, excluding those forecasted transactions related to the payment of variable interest on existing financial instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 45

-Subparagraph b(3)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=6887037&loc=d3e80748-113994

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- Definition

Aggregate notional amount of all foreign currency derivatives designated as hedging instruments in cash flow hedges. Notional amount refers to the number of currency units specified in the foreign currency derivative contract.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 1B

-URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Notional Amount

-URI http://asc.fasb.org/extlink&oid=6519104

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 1A

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5579245-113959

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- Definition

Aggregate notional amount of all foreign currency derivatives not designated as hedging instruments. Notional amount refers to the number of currency units specified in the foreign currency derivative contract.

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- Definition

Aggregate notional amount of all interest rate derivatives designated as hedging instruments in fair value hedges. Notional amount refers to the monetary amount specified in the interest rate derivative contract.

+ References

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- Definition

Aggregate notional amount of all price risk derivatives designated as hedging instruments in cash flow hedges. Notional amount refers to the number of currency units specified in the price risk derivative contract. Excludes notional amount expressed in nonmonetary terms such as for a commodity forward contract.

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Aggregate notional amount of all price risk derivatives not designated as hedging instruments. Notional amount refers to the number of currency units specified in the foreign currency derivative contract.

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