Comprehensive Income - Pre-tax Amounts Reclassified from AOCI into the Condensed Consolidated Statements of Operations (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2018	Jul. 01, 2017	Jun. 30, 2018	Jul. 01, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net sales	$ (53,265)	$ (45,408)	$ (202,695)	$ (176,655)
Cost of sales	32,844	27,920	124,940	108,400
Other income/(expense), net	(672)	(540)	(1,702)	(1,948)
Total amounts reclassified from AOCI	(13,284)	(11,308)	(56,482)	(50,172)
Reclassifications out of AOCI
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total amounts reclassified from AOCI	1,263	(633)	1,022	(1,448)
Reclassifications out of AOCI | Unrealized (gains)/losses on derivative instruments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total amounts reclassified from AOCI	1,232	(585)	1,071	(1,411)
Reclassifications out of AOCI | Unrealized (gains)/losses on derivative instruments | Foreign exchange contracts
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net sales	162	(148)	433	(657)
Cost of sales	206	(73)	200	(630)
Other income/(expense), net	864	(364)	441	(127)
Reclassifications out of AOCI | Unrealized (gains)/losses on derivative instruments | Interest rate contracts
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other income/(expense), net	0	0	(3)	3
Reclassifications out of AOCI | Unrealized (gains)/losses on marketable securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other income/(expense), net	$ 31	$ (48)	$ (49)	$ (37)