Pension And Postretirement Benefits (Schedule Of Effect Of One-Percentage-Point Change In Assumed Health Care Costs) (Details) - Other Postretirement Benefit Plan, Defined Benefit [Member] $ in Millions	12 Months Ended
	Jul. 30, 2017 USD ($)
Defined Benefit Plan, Assumed Health Care Cost Trend Rates [Abstract]
Defined Benefit Plan, Effect of One Percentage Point Increase on Service and Interest Cost Components	$ 0
Defined Benefit Plan, Effect of One Percentage Point Decrease on Service and Interest Cost Components	0
Defined Benefit Plan, Effect of One Percentage Point Increase on Accumulated Postretirement Benefit Obligation	3
Defined Benefit Plan, Effect of One Percentage Point Decrease on Accumulated Postretirement Benefit Obligation	$ (3)