Changes in Accumulated Other Comprehensive Loss, Net of Tax (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2022	Jan. 01, 2022
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning Balance	$ (4,119)	$ (6,440)
Unrealized gains (losses) arising during the period	(221)	59
Reclassifications of realized net (gains) losses to net income	(138)	105
AOCI, Ending Balance	(4,478)	(6,276)
Market Value Adjustments for Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning Balance	625	(110)
Unrealized gains (losses) arising during the period	(375)	64
Reclassifications of realized net (gains) losses to net income	(167)	(14)
AOCI, Ending Balance	83	(60)
Unrecognized Pension and  Postretirement Medical  Expense
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning Balance	(2,869)	(5,372)
Unrealized gains (losses) arising during the period	0	36
Reclassifications of realized net (gains) losses to net income	1	119
AOCI, Ending Balance	(2,868)	(5,217)
Foreign Currency Translation and Other
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning Balance	(1,875)	(958)
Unrealized gains (losses) arising during the period	154	(41)
Reclassifications of realized net (gains) losses to net income	28	0
AOCI, Ending Balance	$ (1,693)	$ (999)