Stock-based Compensation (Schedule Of Stock Option Activity) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended
	Oct. 29, 2017	Oct. 30, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Beginning of year, Options	1,042
Granted, Options	575
Exercised, Options	0	0
Terminated, Options	0
End of year, Options	1,617
Exercisable at end of period, Options	544
Beginning of period, Weighted-Average Exercise Price	$ 52.08
Granted, Weighted-Average Exercise Price	47.19
Exercised, Weighted-Average Exercise Price	0.00
Terminated, Weighted-Average Exercise Price	0.00
End of period, Weighted-Average Exercise Price	50.34
Exercisable at end of period, Weighted-Average Exercise Price	$ 51.40
Outstanding at end of period, Weighted-Average Remaining Contractual Life (In years)	8 years 11 months
Exercisable at end of period, Weighted-Average Remaining Contractual Life (In years)	8 years 2 months
Outstanding at end of period, Aggregate Intrinsic Value	$ 1
Exercisable at end of period, Aggregate Intrinsic Value	$ 0