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Commitments and Contingencies - Leases (Details) - USD ($) $ in Millions | Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2023
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Leases |  |  |  |
Estimated future decommissioning cost | [1] | $ 10,414 | $ 10,806 | $ 7,489
[1] | (1) Includes $313 million and $283 million at September 30, 2025 and 2024, respectively, in Current liabilities.

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- Definition Leases [Line Items] + References No definition available. + Details
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- Definition The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 410 -SubTopic 20 -Name Accounting Standards Codification -Section 25 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481999/410-20-25-4 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 410 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481850/410-20-50-1 + Details
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