Nonconsolidated Partially-Owned Affiliates - Narrative (Details) - USD ($) $ in Millions	Jun. 30, 2025	Sep. 30, 2024
Equity Method Investments and Joint Ventures [Abstract]
Total investments in partially-owned affiliates	$ 294	$ 338

Amount of investment in equity method investee and investment in and advance to affiliate.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(18))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant