Equity Changes in Accumulated Other Comprehensive Loss, Tax (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2022	Jan. 01, 2022
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI Tax, Attributable to Parent, Beginning Balance	$ 861	$ 1,784
Unrealized gains (losses) arising during the period	108	(38)
Reclassifications of realized net (gains) losses to net income	37	(32)
AOCI Tax, Attributable to Parent, Ending Balance	1,006	1,714
Market Value Adjustments for Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI Tax, Attributable to Parent, Beginning Balance	(179)	42
Unrealized gains (losses) arising during the period	100	(23)
Reclassifications of realized net (gains) losses to net income	51	4
AOCI Tax, Attributable to Parent, Ending Balance	(28)	23
Unrecognized Pension and  Postretirement Medical  Expense
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI Tax, Attributable to Parent, Beginning Balance	901	1,653
Unrealized gains (losses) arising during the period	0	(11)
Reclassifications of realized net (gains) losses to net income	0	(36)
AOCI Tax, Attributable to Parent, Ending Balance	901	1,606
Foreign Currency Translation and Other
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI Tax, Attributable to Parent, Beginning Balance	139	89
Unrealized gains (losses) arising during the period	8	(4)
Reclassifications of realized net (gains) losses to net income	(14)	0
AOCI Tax, Attributable to Parent, Ending Balance	$ 133	$ 85