Financial Instruments (Schedule Of Changes In Cash Flow Hedges In Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended
	Oct. 27, 2019	Oct. 28, 2018
Derivative Instruments, Gain (Loss) [Line Items]
OCI before tax accumulated derivative gain (loss) beginning of period	$ (11)	$ (8)
OCI before tax accumulated derivative gain (loss) end of period	(9)	(7)
Foreign Exchange Forward | Loss from discontinued operations [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	1	0
Interest Rate Contract [Member] | Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	$ 1	$ 1