Segment Information and Geographic Data - Summary Information by Reportable Segment (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 26, 2020	Dec. 28, 2019
Segment Reporting Information [Line Items]
Net sales	$ 111,439	$ 91,819
Operating income	33,534	25,569
Americas
Segment Reporting Information [Line Items]
Net sales	46,310	41,367
Operating income	15,785	13,092
Europe
Segment Reporting Information [Line Items]
Net sales	27,306	23,273
Operating income	9,589	7,719
Greater China
Segment Reporting Information [Line Items]
Net sales	21,313	13,578
Operating income	8,530	5,363
Japan
Segment Reporting Information [Line Items]
Net sales	8,285	6,223
Operating income	3,503	2,778
Rest of Asia Pacific
Segment Reporting Information [Line Items]
Net sales	8,225	7,378
Operating income	$ 2,953	$ 2,731