Equity Changes in Accumulated Other Comprehensive Loss, Tax (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 30, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI Tax, Attributable to Parent, Beginning Balance	$ 1,994	$ 2,395
Other Comprehensive Income (Loss) before Reclassifications, Tax	(29)	(247)
Reclassification from AOCI, Current Period, Tax	(43)	(14)
AOCI Tax, Attributable to Parent, Ending Balance	1,922	2,134
Investments
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI Tax, Attributable to Parent, Beginning Balance	(7)	(18)
Other Comprehensive Income (Loss) before Reclassifications, Tax	0	7
Reclassification from AOCI, Current Period, Tax	0	0
AOCI Tax, Attributable to Parent, Ending Balance	(7)	(11)
Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI Tax, Attributable to Parent, Beginning Balance	46	13
Other Comprehensive Income (Loss) before Reclassifications, Tax	(13)	(182)
Reclassification from AOCI, Current Period, Tax	(8)	26
AOCI Tax, Attributable to Parent, Ending Balance	25	(143)
Unrecognized Pension and Postretirement Medical Expense
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI Tax, Attributable to Parent, Beginning Balance	1,839	2,208
Other Comprehensive Income (Loss) before Reclassifications, Tax	0	(22)
Reclassification from AOCI, Current Period, Tax	(35)	(40)
AOCI Tax, Attributable to Parent, Ending Balance	1,804	2,146
Foreign Currency Translation and Other
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI Tax, Attributable to Parent, Beginning Balance	116	192
Other Comprehensive Income (Loss) before Reclassifications, Tax	(16)	(50)
Reclassification from AOCI, Current Period, Tax	0	0
AOCI Tax, Attributable to Parent, Ending Balance	$ 100	$ 142