Income Taxes - Summary of Income Tax Holiday (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Tax reductions related to tax holidays	$ 248	$ 136	$ (43)
Income Tax Holiday, Income Tax Benefits Per Share	$ 0.85	$ 0.48	$ (0.16)
Income taxes paid, net	$ 670	$ 518	$ 536

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- Definition

The amount of income taxes from which a reporting entity is exempt or for which it will receive a reduction in income taxes as a result of the income tax holiday granted by the taxing jurisdiction.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 11.C)
-URI http://asc.fasb.org/extlink&oid=122134291&loc=d3e330215-122817

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- Definition

Per share amount effect of the income tax benefit resulting from the income tax holidays granted by taxing jurisdictions.

+ References

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- Definition

The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income, net of any cash received during the current period as refunds for the overpayment of taxes.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=123431023&loc=d3e4297-108586

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