Changes in Accumulated Other Comprehensive Loss, Net of Tax (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Jun. 29, 2019	Jun. 30, 2018	Jun. 29, 2019	Jun. 30, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning Balance		$ (3,786)	$ (3,345)	$ (3,097)	$ (3,528)
Unrealized gains (losses) arising during the period		54	(9)	10	0
Reclassifications of realized net (gains) losses to net income		11	92	72	266
AOCI reclassifications to retained earnings, net of tax	[1]			(706)
AOCI, Ending Balance		(3,721)	(3,262)	(3,721)	(3,262)
Investments
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning Balance		(4)	14	15	8
Unrealized gains (losses) arising during the period		3	1	(1)	7
Reclassifications of realized net (gains) losses to net income		0	0	0	0
AOCI reclassifications to retained earnings, net of tax	[1]			(15)
AOCI, Ending Balance		(1)	15	(1)	15
Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning Balance		48	(156)	145	(62)
Unrealized gains (losses) arising during the period		27	240	(15)	106
Reclassifications of realized net (gains) losses to net income		(42)	20	89	(60)
AOCI reclassifications to retained earnings, net of tax	[1]			(8)
AOCI, Ending Balance		33	104	33	104
Unrecognized Pension and Postretirement Medical Expense
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning Balance		(3,179)	(2,912)	(2,633)	(3,067)
Unrealized gains (losses) arising during the period		(29)	(2)	(16)	19
Reclassifications of realized net (gains) losses to net income		53	72	(161)	(206)
AOCI reclassifications to retained earnings, net of tax	[1]			(667)
AOCI, Ending Balance		(3,155)	(2,842)	(3,155)	(2,842)
Foreign Currency Translation and Other
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning Balance		(651)	(291)	(624)	(407)
Unrealized gains (losses) arising during the period		53	(248)	42	(132)
Reclassifications of realized net (gains) losses to net income		0	0	0	0
AOCI reclassifications to retained earnings, net of tax	[1]			(16)
AOCI, Ending Balance		$ (598)	$ (539)	$ (598)	$ (539)

[1] At the beginning of fiscal 2019, the Company adopted new FASB accounting guidance, Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income, and reclassified $691 million from AOCI to retained earnings. In addition, at the beginning of fiscal 2019, the Company adopted new FASB accounting guidance, Recognition and Measurement of Financial Assets and Liabilities, and reclassified $24 million ($15 million after tax) of market value adjustments on investments previously recorded in AOCI to retained earnings.