Comprehensive Income - Pre-tax Amounts Reclassified from AOCI into the Condensed Consolidated Statements of Operations (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Mar. 31, 2018	Apr. 01, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net sales	$ (61,137)	$ (52,896)	$ (149,430)	$ (131,247)
Cost of sales	37,715	32,305	92,096	80,480
Other income/(expense), net	(274)	(587)	(1,030)	(1,408)
Total amounts reclassified from AOCI	(16,168)	(14,684)	(43,198)	(38,864)
Reclassifications out of AOCI
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total amounts reclassified from AOCI	(248)	(1,363)	(241)	(815)
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	(284)	(1,343)	(161)	(826)
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	87	(408)	271	(509)
Cost of sales	21	(570)	(6)	(557)
Other income/(expense), net	(390)	(367)	(423)	237
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	(2)	2	(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	$ 36	$ (20)	$ (80)	$ 11