Pension And Postretirement Benefits (Schedule Of Components of Benefit Expense) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jan. 29, 2017	Jan. 31, 2016	Jan. 29, 2017	Jan. 31, 2016
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Defined Benefit Plan, Service Cost	$ 7	$ 7	$ 13	$ 14
Defined Benefit Plan, Interest Cost	21	25	43	50
Expected return on plan assets	(36)	(36)	(72)	(75)
Amortization of Prior Service Cost (Credit)	0	0	0	0
Defined Benefit Plan, Actuarial Gain (Loss)	0	(24)	0	112
Defined Benefit Plan, Net Periodic Benefit Cost	(8)	(28)	(16)	101
Other Postretirement Benefit Plan [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Defined Benefit Plan, Service Cost	1	1	1	1
Defined Benefit Plan, Interest Cost	2	4	5	8
Expected return on plan assets	0	0	0	0
Amortization of Prior Service Cost (Credit)	(7)	(1)	(13)	(1)
Defined Benefit Plan, Actuarial Gain (Loss)	0	0	0	0
Defined Benefit Plan, Net Periodic Benefit Cost	$ (4)	$ 4	$ (7)	$ 8