Equity Changes in Accumulated Other Comprehensive Loss, Tax (Details) - USD ($) $ in Millions	3 Months Ended
	Jan. 01, 2022	Jan. 02, 2021
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI Tax, Attributable to Parent, Beginning Balance	$ 1,784	$ 2,380
Unrealized gains (losses) arising during the period	(38)	38
Reclassifications of realized net (gains) losses to net income	(32)	(36)
AOCI Tax, Attributable to Parent, Ending Balance	1,714	2,382
Market Value Adjustments for Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI Tax, Attributable to Parent, Beginning Balance	42	40
Unrealized gains (losses) arising during the period	(23)	46
Reclassifications of realized net (gains) losses to net income	4	9
AOCI Tax, Attributable to Parent, Ending Balance	23	95
Unrecognized Pension and  Postretirement Medical  Expense
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI Tax, Attributable to Parent, Beginning Balance	1,653	2,201
Unrealized gains (losses) arising during the period	(11)	(1)
Reclassifications of realized net (gains) losses to net income	(36)	(45)
AOCI Tax, Attributable to Parent, Ending Balance	1,606	2,155
Foreign Currency Translation and Other
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI Tax, Attributable to Parent, Beginning Balance	89	139
Unrealized gains (losses) arising during the period	(4)	(7)
Reclassifications of realized net (gains) losses to net income	0	0
AOCI Tax, Attributable to Parent, Ending Balance	$ 85	$ 132