Segment Information and Geographic Data - Summary Information by Reportable Segment (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 30, 2019	Mar. 31, 2018	Mar. 30, 2019	Mar. 31, 2018
Segment Reporting Information [Line Items]
Net sales	$ 58,015	$ 61,137	$ 142,325	$ 149,430
Operating income	13,415	15,894	36,761	42,168
Americas
Segment Reporting Information [Line Items]
Net sales	25,596	24,841	62,536	60,034
Operating income	7,687	7,768	18,887	19,084
Europe
Segment Reporting Information [Line Items]
Net sales	13,054	13,846	33,417	34,900
Operating income	4,026	4,259	10,684	11,152
Greater China
Segment Reporting Information [Line Items]
Net sales	10,218	13,024	23,387	30,980
Operating income	3,607	4,963	8,921	11,871
Japan
Segment Reporting Information [Line Items]
Net sales	5,532	5,468	12,442	12,705
Operating income	2,390	2,346	5,404	5,428
Rest of Asia Pacific
Segment Reporting Information [Line Items]
Net sales	3,615	3,958	10,543	10,811
Operating income	$ 1,096	$ 1,278	$ 3,656	$ 3,853