Vehicle Rental Activities (Narrative) (Details) - USD ($) $ in Millions	Mar. 31, 2025	Mar. 31, 2024
Property, Plant and Equipment [Abstract]
Liabilities under vehicle programs	$ 449	$ 483
Other receivables	$ 231	$ 239

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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-Publisher FASB
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
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-Name Accounting Standards Codification
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
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-Topic 944
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-Name Accounting Standards Codification
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Name:	us-gaap_OtherReceivables
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant