Financial Instruments (Narrative) (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
Jan. 27, 2019	Jul. 29, 2018
Derivatives, Fair Value [Line Items]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	$ 1
Cash Flow Hedge Ineffectiveness is Immaterial	The ineffective portion and amount excluded from effectiveness testing were not material.
Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Margin Deposit Assets	$ 7	$ 2
Foreign Exchange Contract [Member]
Derivatives, Fair Value [Line Items]
Contracts Mature Within, Months	18 months
Commodity Derivative Contracts [Member]
Derivatives, Fair Value [Line Items]
Maximum Length of Contract Maturity	18 months
Deferred Compensation Derivative Contracts [Member]
Derivatives, Fair Value [Line Items]
Maximum Length of Contract Maturity	12 months
Derivatives Designated As Hedges [Member] \| Foreign Exchange Contract [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	$ 79	104
Derivatives Designated As Hedges [Member] \| Commodity Derivative Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	0	0
Derivatives Not Designated As Hedges [Member] \| Foreign Exchange Contract [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	157	140
Derivatives Not Designated As Hedges [Member] \| Currency Swap [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	0	0
Derivatives Not Designated As Hedges [Member] \| Commodity Derivative Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	165	118
Derivatives Not Designated As Hedges [Member] \| Embedded Derivative Financial Instruments [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	59	33
Derivatives Not Designated As Hedges [Member] \| Deferred Compensation Derivative Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	$ 41	$ 41
Wal-Mart Stores, Inc. [Member] \| Customer Concentration Risk [Member] \| Sales Revenue, Net [Member]
Derivatives, Fair Value [Line Items]
Entity Wide Revenue, Major Customer, Percentage Of Net Sales		18.00%
Top Five Customers [Member] \| Customer Concentration Risk [Member] \| Sales Revenue, Net [Member]
Derivatives, Fair Value [Line Items]
Entity Wide Revenue, Major Customer, Percentage Of Net Sales		38.00%

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 1
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A disclosure of an assertion that the amount of cash flow hedge ineffectiveness is immaterial.

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For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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The amount of cash or securities placed with a broker or counterparty as security for a trading or derivatives securities position which was partially obtained with funds provided by the broker dealer.

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Maximum period of time the entity is hedging its exposure to variability in future cash flows for forecasted transactions, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Excludes forecasted transactions related to payment of variable interest on existing financial instruments.

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Maximum period 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, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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