Fair Value Measurements and Investments - Assets and Liabilities Measured (Details) - USD ($) $ in Millions	Sep. 30, 2022	Sep. 30, 2021
Assets
Investment securities	$ 5,261
Liabilities
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Liabilities	Liabilities
Fair Value, Measurements, Recurring \| Level 1
Assets
Total	$ 16,999	$ 17,658
Liabilities
Deferred compensation liability	146	167
Derivative instruments	0	0
Total	146	167
Fair Value, Measurements, Recurring \| Level 1 \| Money market funds
Assets
Cash equivalents and restricted cash equivalents:	11,736	11,779
Other current and non-current assets:	22	4
Fair Value, Measurements, Recurring \| Level 1 \| U.S. government-sponsored debt securities
Assets
Cash equivalents and restricted cash equivalents:	0	0
Investment securities	0	0
Fair Value, Measurements, Recurring \| Level 1 \| Marketable equity securities
Assets
Marketable equity securities	437	490
Fair Value, Measurements, Recurring \| Level 1 \| U.S. Treasury securities
Assets
Cash equivalents and restricted cash equivalents:	799	2,400
Investment securities	4,005	2,985
Fair Value, Measurements, Recurring \| Level 1 \| Derivative instruments
Assets
Other current and non-current assets:	0	0
Fair Value, Measurements, Recurring \| Level 2
Assets
Total	1,588	755
Liabilities
Deferred compensation liability	0	0
Derivative instruments	418	109
Total	418	109
Fair Value, Measurements, Recurring \| Level 2 \| Money market funds
Assets
Cash equivalents and restricted cash equivalents:	0	0
Other current and non-current assets:	0	0
Fair Value, Measurements, Recurring \| Level 2 \| U.S. government-sponsored debt securities
Assets
Cash equivalents and restricted cash equivalents:	0	100
Investment securities	457	245
Fair Value, Measurements, Recurring \| Level 2 \| Marketable equity securities
Assets
Marketable equity securities	0	0
Fair Value, Measurements, Recurring \| Level 2 \| U.S. Treasury securities
Assets
Cash equivalents and restricted cash equivalents:	0	0
Investment securities	0	0
Fair Value, Measurements, Recurring \| Level 2 \| Derivative instruments
Assets
Other current and non-current assets:	$ 1,131	$ 410

Fair value portion of accrued expenses.

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Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes 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.

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Fair value of financial and nonfinancial obligations.

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Fair value portion of other assets.

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Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading) and investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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