Financial Instruments - Restricted Cash (Details) - USD ($) $ in Millions	Jun. 26, 2021	Sep. 26, 2020	Jun. 27, 2020	Sep. 28, 2019
Supplemental Cash Flow Elements [Abstract]
Cash and cash equivalents	$ 34,050	$ 38,016
Restricted cash	$ 1,226	$ 1,773
Restricted cash and cash equivalents, noncurrent, asset, statement of financial position [Extensible List]	Other non-current assets	Other non-current assets
Cash, cash equivalents and restricted cash	$ 35,276	$ 39,789	$ 35,039	$ 50,224

Amount of cash and cash equivalents, and cash and cash equivalents restricted to withdrawal or usage. Excludes amount for disposal group and discontinued operations. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 24
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3521-108585

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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-Section 45
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
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-URI http://asc.fasb.org/extlink&oid=121583591&loc=SL98516268-108586

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