Debt - Summary of Cash Flows Associated with Commercial Paper (Details) - USD ($) $ in Millions	12 Months Ended
Sep. 26, 2020	Sep. 28, 2019	Sep. 29, 2018
Maturities 90 days or less:
Proceeds from/(Repayments of) commercial paper, net	$ 100	$ (3,248)	$ 1,044
Maturities greater than 90 days:
Proceeds from commercial paper	6,185	13,874	14,555
Repayments of commercial paper	(7,248)	(16,603)	(15,636)
Repayments of commercial paper, net	(1,063)	(2,729)	(1,081)
Total repayments of commercial paper, net	$ (963)	$ (5,977)	$ (37)

The net cash inflow or cash outflow from issuing (borrowing) and repaying commercial paper.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3255-108585

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 9
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3098-108585

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3291-108585

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- Definition

The cash inflow from a borrowing net of the cash outflow from repayment of a borrowing having initial term of repayment of more than three months but less than one year or one operating cycle (if the normal cycle is more than one year).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-04(a))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e24072-122690

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- References

No definition available.

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- Definition

The cash inflow from a borrowing net of the cash outflow from repayment of a borrowing having initial term of repayment within three months.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3255-108585

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3291-108585

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 9
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3098-108585

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- Definition

The cash inflow from a borrowing having initial term of repayment of more than three months but less than one year or one operating cycle (if the normal cycle is more than one year).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
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The cash outflow from a repayment of a borrowing having initial term of repayment of more than three months but less than one year or one operating cycle (if the normal cycle is more than one year).

+ References

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