Equity Changes in Accumulated Other Comprehensive Loss, Before Tax (Detail) - USD ($) $ in Millions	12 Months Ended
	Oct. 01, 2022	Oct. 02, 2021	Oct. 03, 2020
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI before Tax, Attributable to Parent, Beginning Balance	$ (8,224)	$ (10,702)	$ (8,459)
Unrealized gains (losses) arising during the period	2,766	1,693	(2,527)
Reclassifications of realized net (gains) losses to net income	478	785	284
AOCI before Tax, Attributable to Parent, Ending Balance	(4,980)	(8,224)	(10,702)
Market Value Adjustments for Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI before Tax, Attributable to Parent, Beginning Balance	(152)	(191)	129
Unrealized gains (losses) arising during the period	1,098	70	(57)
Reclassifications of realized net (gains) losses to net income	(142)	(31)	(263)
AOCI before Tax, Attributable to Parent, Ending Balance	804	(152)	(191)
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)	(7,502)
Unrealized gains (losses) arising during the period	2,635	1,582	(2,468)
Reclassifications of realized net (gains) losses to net income	620	816	547
AOCI before Tax, Attributable to Parent, Ending Balance	(3,770)	(7,025)	(9,423)
Foreign Currency Translation and Other
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI before Tax, Attributable to Parent, Beginning Balance	(1,047)	(1,088)	(1,086)
Unrealized gains (losses) arising during the period	(967)	41	(2)
Reclassifications of realized net (gains) losses to net income	0	0	0
AOCI before Tax, Attributable to Parent, Ending Balance	$ (2,014)	$ (1,047)	$ (1,088)