Changes in Accumulated Other Comprehensive Loss, Net of Tax (Details) - USD ($) $ in Millions		3 Months Ended
		Jan. 02, 2021	Dec. 28, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning Balance		$ (8,322)	$ (6,617)
Unrealized gains (losses) arising during the period		66	23
Reclassifications of realized net (gains) losses to net income		115	61
AOCI, Ending Balance		(8,141)	(6,533)
Accumulated Net Gain (Loss) from Market Value Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning Balance	[1]	(151)	100
Unrealized gains (losses) arising during the period	[1]	(139)	(61)
Reclassifications of realized net (gains) losses to net income	[1]	(34)	(46)
AOCI, Ending Balance	[1]	(324)	(7)
Unrecognized Pension and  Postretirement Medical  Expense
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning Balance		(7,222)	(5,746)
Unrealized gains (losses) arising during the period		1	0
Reclassifications of realized net (gains) losses to net income		149	107
AOCI, Ending Balance		(7,072)	(5,639)
Foreign Currency Translation and Other
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning Balance		(949)	(971)
Unrealized gains (losses) arising during the period		204	84
Reclassifications of realized net (gains) losses to net income		0	0
AOCI, Ending Balance		$ (745)	$ (887)

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