Equity Changes in Accumulated Other Comprehensive Loss, Tax (Details) - USD ($) $ in Millions	12 Months Ended
	Oct. 01, 2022	Oct. 02, 2021	Oct. 03, 2020
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI Tax, Attributable to Parent, Beginning Balance	$ 1,784	$ 2,380	$ 1,842
Unrealized gains (losses) arising during the period	(812)	(416)	604
Reclassifications of realized net (gains) losses to net income	(111)	(180)	(66)
AOCI Tax, Attributable to Parent, Ending Balance	861	1,784	2,380
Market Value Adjustments for Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI Tax, Attributable to Parent, Beginning Balance	42	40	(29)
Unrealized gains (losses) arising during the period	(254)	(8)	8
Reclassifications of realized net (gains) losses to net income	33	10	61
AOCI Tax, Attributable to Parent, Ending Balance	(179)	42	40
Unrecognized Pension and Postretirement Medical Expense
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI Tax, Attributable to Parent, Beginning Balance	1,653	2,201	1,756
Unrealized gains (losses) arising during the period	(608)	(358)	572
Reclassifications of realized net (gains) losses to net income	(144)	(190)	(127)
AOCI Tax, Attributable to Parent, Ending Balance	901	1,653	2,201
Foreign Currency Translation and Other
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI Tax, Attributable to Parent, Beginning Balance	89	139	115
Unrealized gains (losses) arising during the period	50	(50)	24
Reclassifications of realized net (gains) losses to net income	0	0	0
AOCI Tax, Attributable to Parent, Ending Balance	$ 139	$ 89	$ 139