Equity Changes in Accumulated Other Comprehensive Loss, Before Tax (Details) - USD ($) $ in Millions		3 Months Ended				6 Months Ended
		Apr. 03, 2021		Mar. 28, 2020		Apr. 03, 2021	Mar. 28, 2020
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI before Tax, Attributable to Parent, Beginning Balance		$ (10,523)		$ (8,379)		$ (10,702)	$ (8,459)
Other Comprehensive Income (Loss), before Reclassifications, before Tax		102		(195)		130	(194)
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax		199		96		350	175
AOCI before Tax, Attributable to Parent, Ending Balance		(10,222)		(8,478)		(10,222)	(8,478)
Accumulated Net Gain (Loss) from Market Value Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI before Tax, Attributable to Parent, Beginning Balance		(419)	[1]	(12)	[1]	(191)	129
Other Comprehensive Income (Loss), before Reclassifications, before Tax		131	[1]	212	[1]	(54)	131
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax		5	[1]	(42)	[1]	(38)	(102)
AOCI before Tax, Attributable to Parent, Ending Balance	[1]	(283)		158		(283)	158
Unrecognized Pension and  Postretirement Medical  Expense
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI before Tax, Attributable to Parent, Beginning Balance		(9,227)		(7,363)		(9,423)	(7,502)
Other Comprehensive Income (Loss), before Reclassifications, before Tax		55		(43)		57	(43)
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax		194		138		388	277
AOCI before Tax, Attributable to Parent, Ending Balance		(8,978)		(7,268)		(8,978)	(7,268)
Foreign Currency Translation and Other
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI before Tax, Attributable to Parent, Beginning Balance		(877)		(1,004)		(1,088)	(1,086)
Other Comprehensive Income (Loss), before Reclassifications, before Tax		(84)		(364)		127	(282)
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax		0		0		0	0
AOCI before Tax, Attributable to Parent, Ending Balance		$ (961)		$ (1,368)		$ (961)	$ (1,368)

[1] Primarily reflects market value adjustments for cash flow hedges.