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Financial Instruments (Schedule Of The Fair Value Of Derivative Instruments) (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Apr. 26, 2020	Jan. 26, 2020	Apr. 28, 2019	Apr. 26, 2020	Apr. 28, 2019	Jul. 28, 2019
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 11			$ 11		$ 5
Derivative Liability, Fair Value, Gross Liability	26			26		10
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	35		$ 2	26	$ 6
Treasury Lock [Member] \| Interest Expense [Member]
Derivatives, Fair Value [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	0	$ (3)	$ 0	(3)	$ 0
Derivatives Designated As Hedges [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	7			7		0
Derivative Liability, Fair Value, Gross Liability	0			0		2
Derivatives Designated As Hedges [Member] \| Foreign Exchange Forward Contracts [Member] \| Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	7			7		0
Derivatives Designated As Hedges [Member] \| Foreign Exchange Forward Contracts [Member] \| Discontinued Operations, Held-for-sale or Disposed of by Sale [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	0			0		2
Derivatives Not Designated As Hedges [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	4			4		5
Derivative Liability, Fair Value, Gross Liability	26			26		8
Derivatives Not Designated As Hedges [Member] \| Foreign Exchange Forward Contracts [Member] \| Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0			0		1
Derivatives Not Designated As Hedges [Member] \| Foreign Exchange Forward Contracts [Member] \| Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	0			0		2
Derivatives Not Designated As Hedges [Member] \| Commodity Derivative Contracts [Member] \| Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	3			3		3
Derivatives Not Designated As Hedges [Member] \| Commodity Derivative Contracts [Member] \| Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	25			25		6
Derivatives Not Designated As Hedges [Member] \| Commodity Derivative Contracts [Member] \| Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	1			1		0
Derivatives Not Designated As Hedges [Member] \| Deferred Compensation Derivative Contracts [Member] \| Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 1			$ 1		$ 1