Vehicle Rental Activities (Narrative) (Details) - USD ($) $ in Millions	Sep. 30, 2024	Sep. 30, 2023
Property, Plant and Equipment [Abstract]
Liabilities under vehicle programs	$ 152	$ 206
Other receivables	$ 284	$ 252

Amount due from parties in nontrade transactions, classified as other.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
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-Topic 946
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Name:	us-gaap_OtherReceivables
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant