Equity Changes in Accumulated Other Comprehensive Loss, Before Tax (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 28, 2020	Mar. 30, 2019	Mar. 28, 2020	Mar. 30, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI before Tax, Attributable to Parent, Beginning Balance	$ (8,379)	$ (4,831)	$ (8,459)	$ (4,849)
Other Comprehensive Income (Loss), before Reclassifications, before Tax	(195)	(53)	(194)	(42)
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	96	50	175	80
AOCI reclassifications to retained earnings, before tax				(23)
AOCI before Tax, Attributable to Parent, Ending Balance	(8,478)	(4,834)	(8,478)	(4,834)
Investments
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI before Tax, Attributable to Parent, Beginning Balance	0	0	0	24
Other Comprehensive Income (Loss), before Reclassifications, before Tax	0	(5)	0	(5)
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	0	0	0	0
AOCI reclassifications to retained earnings, before tax				(24)
AOCI before Tax, Attributable to Parent, Ending Balance	0	(5)	0	(5)
Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI before Tax, Attributable to Parent, Beginning Balance	(12)	166	129	177
Other Comprehensive Income (Loss), before Reclassifications, before Tax	212	(82)	131	(55)
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	(42)	(22)	(102)	(61)
AOCI reclassifications to retained earnings, before tax				1
AOCI before Tax, Attributable to Parent, Ending Balance	158	62	158	62
Unrecognized Pension and  Postretirement Medical  Expense
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI before Tax, Attributable to Parent, Beginning Balance	(7,363)	(4,254)	(7,502)	(4,323)
Other Comprehensive Income (Loss), before Reclassifications, before Tax	(43)	19	(43)	19
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	138	72	277	141
AOCI reclassifications to retained earnings, before tax				0
AOCI before Tax, Attributable to Parent, Ending Balance	(7,268)	(4,163)	(7,268)	(4,163)
Foreign Currency Translation and Other
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI before Tax, Attributable to Parent, Beginning Balance	(1,004)	(743)	(1,086)	(727)
Other Comprehensive Income (Loss), before Reclassifications, before Tax	(364)	15	(282)	(1)
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	0	0	0	0
AOCI reclassifications to retained earnings, before tax				0
AOCI before Tax, Attributable to Parent, Ending Balance	$ (1,368)	$ (728)	$ (1,368)	$ (728)