Financial Instruments (Derivatives Not Designated As Hedges) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jan. 27, 2013	Jan. 29, 2012	Jan. 27, 2013	Jan. 29, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Earnings on Derivatives	$ (8)	$ 16	$ (14)	$ 36
Foreign Exchange Forward Contracts [Member] | Cost Of Products Sold [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Earnings on Derivatives	(1)	3	(1)	4
Foreign Exchange Forward Contracts [Member] | Other Expenses/Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Earnings on Derivatives	0	1	0	1
Cross-Currency Swap Contracts [Member] | Other Expenses/Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Earnings on Derivatives	(10)	16	(18)	39
Commodity Derivative Contracts [Member] | Cost Of Products Sold [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Earnings on Derivatives	(1)	(2)	(1)	(7)
Deferred Compensation Derivative Contracts [Member] | Administrative Expenses [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Earnings on Derivatives	$ 4	$ (2)	$ 6	$ (1)