Leases - Lease, Cost (Details) - USD ($) $ in Millions	6 Months Ended
Mar. 31, 2024	Mar. 31, 2023
Leases [Abstract]
Right-of-use assets obtained in exchange for operating lease liabilities	$ 135	$ 215

Amount of increase in right-of-use asset obtained in exchange for operating lease liability.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 53
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479589/842-20-55-53

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (g)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147478964/842-20-50-4

Name:	us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration