Income Taxes - Reconciliation of Beginning and Ending Unrecognized Tax Benefits by Fiscal Year (Detail) - USD ($) $ in Millions |
12 Months Ended | ||
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Sep. 30, 2024 |
Sep. 30, 2023 |
Sep. 30, 2022 |
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| Unrecognized Tax Benefits [Roll Forward] | |||
| Balance as of beginning of period | $ 3,497 | $ 2,683 | $ 2,488 |
| Increase in unrecognized tax benefits related to prior years | 148 | 515 | 10 |
| Decrease in unrecognized tax benefits related to prior years | (322) | (190) | (143) |
| Increase in unrecognized tax benefits related to current year | 556 | 510 | 350 |
| Decrease related to settlements with taxing authorities | (127) | (17) | (19) |
| Reduction related to lapsing statute of limitations | (2) | (4) | (3) |
| Balance as of end of period | $ 3,750 | $ 3,497 | $ 2,683 |
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- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available.
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- Definition Amount of unrecognized tax benefits. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount of decrease in unrecognized tax benefits resulting from settlements with taxing authorities. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount of increase in unrecognized tax benefits resulting from tax positions taken in prior period tax returns. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount of decrease in unrecognized tax benefits resulting from lapses of applicable statutes of limitations. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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