Changes in Accumulated Other Comprehensive Loss, Net of Tax (Details) - USD ($) $ in Millions		3 Months Ended
		Dec. 29, 2018	Dec. 30, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning Balance		$ (3,097)	$ (3,528)
Unrealized gains (losses) arising during the period		(2)	51
Reclassifications of realized net (gains) losses to net income		23	73
AOCI reclassifications to retained earnings, net of tax	[1]	(706)
AOCI, Ending Balance		(3,782)	(3,404)
Investments
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning Balance		15	8
Unrealized gains (losses) arising during the period		0	(1)
Reclassifications of realized net (gains) losses to net income		0	0
AOCI reclassifications to retained earnings, net of tax	[1]	(15)
AOCI, Ending Balance		0	7
Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning Balance		145	(62)
Unrealized gains (losses) arising during the period		21	6
Reclassifications of realized net (gains) losses to net income		(30)	12
AOCI reclassifications to retained earnings, net of tax	[1]	(8)
AOCI, Ending Balance		128	(44)
Unrecognized Pension and Postretirement Medical Expense
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning Balance		(2,633)	(3,067)
Unrealized gains (losses) arising during the period		0	0
Reclassifications of realized net (gains) losses to net income		53	61
AOCI reclassifications to retained earnings, net of tax	[1]	(667)
AOCI, Ending Balance		(3,247)	(3,006)
Foreign Currency Translation and Other
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning Balance		(624)	(407)
Unrealized gains (losses) arising during the period		(23)	46
Reclassifications of realized net (gains) losses to net income		0	0
AOCI reclassifications to retained earnings, net of tax	[1]	(16)
AOCI, Ending Balance		$ (663)	$ (361)

[1] On September 30, 2018, the Company adopted a FASB standard, Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income, and elected to reclassify $691 million from AOCI to retained earnings in the quarter ended December 29, 2018.In addition, on September 30, 2018, the Company adopted a FASB standard, 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.