Revenue Recognition - Net Sales Disaggregated by Significant Products and Services (Details) - USD ($) $ in Millions	3 Months Ended
Dec. 29, 2018	Dec. 30, 2017
Disaggregation of Revenue [Line Items]
Net sales	$ 84,310	$ 88,293
Revenue recognized that was included in deferred revenue at the beginning of the period	2,400	2,000
iPhone
Disaggregation of Revenue [Line Items]
Net sales	51,982	61,104
Mac
Disaggregation of Revenue [Line Items]
Net sales	7,416	6,824
iPad
Disaggregation of Revenue [Line Items]
Net sales	6,729	5,755
Wearables, Home and Accessories
Disaggregation of Revenue [Line Items]
Net sales	7,308	5,481
Services
Disaggregation of Revenue [Line Items]
Net sales	$ 10,875	$ 9,129

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130543-203045

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130539-203045

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130545-203045

Name:	us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration