Equity Changes in Accumulated Other Comprehensive Loss, Before Tax (Details) - USD ($) $ in Millions	3 Months Ended
	Jan. 01, 2022	Jan. 02, 2021
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI before Tax, Attributable to Parent, Beginning Balance	$ (8,224)	$ (10,702)
Unrealized gains (losses) arising during the period	97	28
Reclassifications of realized net (gains) losses to net income	137	151
AOCI before Tax, Attributable to Parent, Ending Balance	(7,990)	(10,523)
Market Value Adjustments for Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI before Tax, Attributable to Parent, Beginning Balance	(152)	(191)
Unrealized gains (losses) arising during the period	87	(185)
Reclassifications of realized net (gains) losses to net income	(18)	(43)
AOCI before Tax, Attributable to Parent, Ending Balance	(83)	(419)
Unrecognized Pension and  Postretirement Medical  Expense
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI before Tax, Attributable to Parent, Beginning Balance	(7,025)	(9,423)
Unrealized gains (losses) arising during the period	47	2
Reclassifications of realized net (gains) losses to net income	155	194
AOCI before Tax, Attributable to Parent, Ending Balance	(6,823)	(9,227)
Foreign Currency Translation and Other
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI before Tax, Attributable to Parent, Beginning Balance	(1,047)	(1,088)
Unrealized gains (losses) arising during the period	(37)	211
Reclassifications of realized net (gains) losses to net income	0	0
AOCI before Tax, Attributable to Parent, Ending Balance	$ (1,084)	$ (877)