Equity Changes in Accumulated Other Comprehensive Loss, Net of Tax (Detail) - USD ($) $ in Millions		12 Months Ended
		Sep. 30, 2017	Oct. 01, 2016	Oct. 03, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning Balance		$ (3,979)	$ (2,421)	$ (1,968)
Unrealized gains (losses) arising during the period		318	(1,559)	(285)
Reclassifications of realized net (gains) losses to net income		133	1	(168)
AOCI, Ending Balance		(3,528)	(3,979)	(2,421)
Market Value Adjustments, Investments
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning Balance		26	13	100
Unrealized gains (losses) arising during the period		(1)	13	(37)
Reclassifications of realized net (gains) losses to net income		(17)	0	(50)
AOCI, Ending Balance		8	26	13
Market Value Adjustments, Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning Balance		(25)	334	204
Unrealized gains (losses) arising during the period		85	(193)	421
Reclassifications of realized net (gains) losses to net income		(122)	(166)	(291)
AOCI, Ending Balance		(62)	(25)	334
Unrecognized Pension and Postretirement Medical Expense
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning Balance		(3,651)	(2,497)	(2,196)
Unrealized gains (losses) arising during the period		312	(1,321)	(474)
Reclassifications of realized net (gains) losses to net income		272	167	173
AOCI, Ending Balance		(3,067)	(3,651)	(2,497)
Foreign Currency Translation and Other(1)
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning Balance	[1]	(329)	(271)	(76)
Unrealized gains (losses) arising during the period	[1]	(78)	(58)	(195)
Reclassifications of realized net (gains) losses to net income	[1]	0	0	0
AOCI, Ending Balance	[1]	$ (407)	$ (329)	$ (271)

[1] (1) Foreign Currency Translation and Other is net of an average 22% estimated tax at September 30, 2017 as the Company has not recognized deferred tax assets for some of our foreign entities.