Equity Changes in Accumulated Other Comprehensive Loss, Net of Tax (Details) - USD ($) $ in Millions	12 Months Ended
	Oct. 01, 2022	Oct. 02, 2021	Oct. 03, 2020
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (6,440)	$ (8,322)	$ (6,617)
Unrealized gains (losses) arising during the period	1,954	1,277	(1,923)
Reclassifications of realized net (gains) losses to net income	367	605	218
Accumulated Other Comprehensive Income (Loss), Net of Tax	(4,119)	(6,440)	(8,322)
Market Value Adjustments for Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(110)	(151)	100
Unrealized gains (losses) arising during the period	844	62	(49)
Reclassifications of realized net (gains) losses to net income	(109)	(21)	(202)
Accumulated Other Comprehensive Income (Loss), Net of Tax	625	(110)	(151)
Unrecognized Pension and Postretirement Medical Expense
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(5,372)	(7,222)	(5,746)
Unrealized gains (losses) arising during the period	2,027	1,224	(1,896)
Reclassifications of realized net (gains) losses to net income	476	626	420
Accumulated Other Comprehensive Income (Loss), Net of Tax	(2,869)	(5,372)	(7,222)
Foreign Currency Translation and Other
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(958)	(949)	(971)
Unrealized gains (losses) arising during the period	(917)	(9)	22
Reclassifications of realized net (gains) losses to net income	0	0	0
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (1,875)	$ (958)	$ (949)