Stock-based Compensation (Schedule Of Stock Option Activity) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	6 Months Ended
	Jan. 27, 2019	Jan. 28, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Beginning of year, Options	1,537
Granted, Options	596
Exercised, Options	0	0
Terminated, Options	(74)
End of year, Options	2,059
Exercisable at end of period, Options	1,035
Beginning of period, Weighted-Average Exercise Price	$ 50.36
Granted, Weighted-Average Exercise Price	35.74
Exercised, Weighted-Average Exercise Price	0.00
Terminated, Weighted-Average Exercise Price	49.05
End of period, Weighted-Average Exercise Price	46.17
Exercisable at end of period, Weighted-Average Exercise Price	$ 50.88
Outstanding at end of period, Weighted-Average Remaining Contractual Life (In years)	7 years 10 months
Exercisable at end of period, Weighted-Average Remaining Contractual Life (In years)	6 years 5 months
Outstanding at end of period, Aggregate Intrinsic Value	$ 0
Exercisable at end of period, Aggregate Intrinsic Value	$ 0