Revenue Recognition - Net Sales Disaggregated by Significant Products and Services (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 29, 2019	Jun. 30, 2018	Jun. 29, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Net sales	$ 53,809	$ 53,265	$ 196,134	$ 202,695
Revenue recognized that was included in deferred revenue at the beginning of the period	2,000	2,000	4,900	4,700
iPhone
Disaggregation of Revenue [Line Items]
Net sales	25,986	29,470	109,019	128,133
Mac
Disaggregation of Revenue [Line Items]
Net sales	5,820	5,258	18,749	17,858
iPad
Disaggregation of Revenue [Line Items]
Net sales	5,023	4,634	16,624	14,397
Wearables, Home and Accessories
Disaggregation of Revenue [Line Items]
Net sales	5,525	3,733	17,962	13,158
Services
Disaggregation of Revenue [Line Items]
Net sales	$ 11,455	$ 10,170	$ 33,780	$ 29,149