Pension And Postretirement Benefits (Schedule of Change in Benefit Obligation) (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 28, 2019	Jul. 29, 2018	Jul. 30, 2017
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Defined Benefit Plan, Benefit Obligation	$ 2,257	$ 2,450
Defined Benefit Plan, Service Cost	21	24	$ 26
Defined Benefit Plan, Interest Cost	82	74	86
Defined Benefit Plan, Benefit Obligation, Actuarial Loss (Gain)	168	(110)
Defined Benefit Plan, Participant Contributions	0	0
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment	0	2
Defined Benefit Plan, Benefits Paid	(154)	(165)
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement	(20)	0
Defined Benefit Plan, Medicare Subsidies	0	0
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Other Change	(1)	(2)
Defined Benefit Plan, Benefit Obligation, Special and Contractual Termination Benefits	0	2
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Curtailment	0	(2)
Defined Benefit Plan, Benefit Obligation, Foreign Currency Translation (Gain) Loss	(8)	(16)
Defined Benefit Plan, Benefit Obligation	2,345	2,257	2,450
Other Postretirement Benefit Plan, Defined Benefit [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Defined Benefit Plan, Benefit Obligation	235	276
Defined Benefit Plan, Service Cost	1	1	1
Defined Benefit Plan, Interest Cost	8	7	10
Defined Benefit Plan, Benefit Obligation, Actuarial Loss (Gain)	14	(16)
Defined Benefit Plan, Participant Contributions	0	1
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment	0	(11)
Defined Benefit Plan, Benefits Paid	(24)	(26)
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement	0	0
Defined Benefit Plan, Medicare Subsidies	1	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	$ 235	$ 276