Equity Changes in Accumulated Other Comprehensive Loss, Before Tax (Details) - USD ($) $ in Millions		3 Months Ended
		Jan. 02, 2021	Dec. 28, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI before Tax, Attributable to Parent, Beginning Balance		$ (10,702)	$ (8,459)
Other Comprehensive Income (Loss), before Reclassifications, before Tax		28	1
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax		151	79
AOCI before Tax, Attributable to Parent, Ending Balance		(10,523)	(8,379)
Accumulated Net Gain (Loss) from Market Value Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI before Tax, Attributable to Parent, Beginning Balance	[1]	(191)	129
Other Comprehensive Income (Loss), before Reclassifications, before Tax	[1]	(185)	(81)
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	[1]	(43)	(60)
AOCI before Tax, Attributable to Parent, Ending Balance	[1]	(419)	(12)
Unrecognized Pension and  Postretirement Medical  Expense
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI before Tax, Attributable to Parent, Beginning Balance		(9,423)	(7,502)
Other Comprehensive Income (Loss), before Reclassifications, before Tax		2	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax		194	139
AOCI before Tax, Attributable to Parent, Ending Balance		(9,227)	(7,363)
Foreign Currency Translation and Other
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI before Tax, Attributable to Parent, Beginning Balance		(1,088)	(1,086)
Other Comprehensive Income (Loss), before Reclassifications, before Tax		211	82
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax		0	0
AOCI before Tax, Attributable to Parent, Ending Balance		$ (877)	$ (1,004)

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