Pension And Postretirement Benefits (Schedule of Change in Benefit Obligation) (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 29, 2018	Jul. 30, 2017	Jul. 31, 2016
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Defined Benefit Plan, Benefit Obligation	$ 2,450	$ 2,626
Defined Benefit Plan, Service Cost	24	26	$ 26
Defined Benefit Plan, Interest Cost	74	86	98
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	(110)	(134)
Defined Benefit Plan, Participant Contributions	0	0
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment	2	0
Defined Benefit Plan, Benefits Paid	(165)	(164)
Defined Benefit Plan, Medicare Subsidies	0	0
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Other Change	(2)	(3)
Defined Benefit Plan, Benefit Obligation, Special and Contractual Termination Benefits	2	0
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Curtailment	(2)	0
Defined Benefit Plan, Benefit Obligation, Foreign Currency Translation Gain (Loss)	(16)	13
Defined Benefit Plan, Benefit Obligation	2,257	2,450	2,626
Other Postretirement Benefit Plan, Defined Benefit [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Defined Benefit Plan, Benefit Obligation	276	313
Defined Benefit Plan, Service Cost	1	1	1
Defined Benefit Plan, Interest Cost	7	10	15
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	(16)	(14)
Defined Benefit Plan, Participant Contributions	1	1
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment	(11)	(12)
Defined Benefit Plan, Benefits Paid	(26)	(26)
Defined Benefit Plan, Medicare Subsidies	3	3
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Other Change	0	0
Defined Benefit Plan, Benefit Obligation, Special and Contractual Termination Benefits	0	0
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Curtailment	0	0
Defined Benefit Plan, Benefit Obligation, Foreign Currency Translation Gain (Loss)	0	0
Defined Benefit Plan, Benefit Obligation	$ 235	$ 276	$ 313