Fair Value Measurements and Investments - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Millions	Dec. 31, 2022	Sep. 30, 2022
Assets
Investment securities	$ 5,754	$ 5,261
Level 1 \| Recurring
Assets
Total	14,836	16,999
Liabilities
Total	184	146
Level 1 \| Recurring \| Derivative instruments
Liabilities
Derivative instruments	0	0
Level 1 \| Recurring \| Deferred compensation liability
Liabilities
Deferred compensation liability	184	146
Level 1 \| Money market funds \| Recurring
Assets
Cash equivalents and restricted cash equivalents:	10,078	11,736
Other current and non-current assets:	22	22
Level 1 \| U.S. government-sponsored debt securities \| Recurring
Assets
Cash equivalents and restricted cash equivalents:	0	0
Investment securities	0	0
Level 1 \| U.S. Treasury securities \| Recurring
Assets
Cash equivalents and restricted cash equivalents:	180	799
Investment securities	4,210	4,005
Level 1 \| Marketable equity securities \| Recurring
Assets
Marketable equity securities	346	437
Level 1 \| Derivative instruments \| Recurring
Assets
Other current and non-current assets:	0	0
Level 2 \| Recurring
Assets
Total	1,609	1,588
Liabilities
Total	398	418
Level 2 \| Recurring \| Derivative instruments
Liabilities
Derivative instruments	398	418
Level 2 \| Recurring \| Deferred compensation liability
Liabilities
Deferred compensation liability	0	0
Level 2 \| Money market funds \| Recurring
Assets
Cash equivalents and restricted cash equivalents:	0	0
Other current and non-current assets:	0	0
Level 2 \| U.S. government-sponsored debt securities \| Recurring
Assets
Cash equivalents and restricted cash equivalents:	400	0
Investment securities	964	457
Level 2 \| U.S. Treasury securities \| Recurring
Assets
Cash equivalents and restricted cash equivalents:	0	0
Investment securities	0	0
Level 2 \| Marketable equity securities \| Recurring
Assets
Marketable equity securities	0	0
Level 2 \| Derivative instruments \| Recurring
Assets
Other current and non-current assets:	$ 245	$ 1,131

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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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Fair value of financial and nonfinancial obligations.

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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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