Changes in Accumulated Other Comprehensive Loss, Net of Tax (Details) - USD ($) $ in Millions	3 Months Ended
	Jan. 01, 2022	Jan. 02, 2021
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning Balance	$ (6,440)	$ (8,322)
Unrealized gains (losses) arising during the period	59	66
Reclassifications of realized net (gains) losses to net income	105	115
AOCI, Ending Balance	(6,276)	(8,141)
Market Value Adjustments for Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning Balance	(110)	(151)
Unrealized gains (losses) arising during the period	64	(139)
Reclassifications of realized net (gains) losses to net income	(14)	(34)
AOCI, Ending Balance	(60)	(324)
Unrecognized Pension and  Postretirement Medical  Expense
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning Balance	(5,372)	(7,222)
Unrealized gains (losses) arising during the period	36	1
Reclassifications of realized net (gains) losses to net income	119	149
AOCI, Ending Balance	(5,217)	(7,072)
Foreign Currency Translation and Other
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning Balance	(958)	(949)
Unrealized gains (losses) arising during the period	(41)	204
Reclassifications of realized net (gains) losses to net income	0	0
AOCI, Ending Balance	$ (999)	$ (745)