Vehicle Rental Activities (Components of Vehicle Depreciation and Lease Charges) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 723	$ 614	$ 1,940	$ 1,631
Lease charges	41	48	115	126
(Gain) loss on sale of vehicles, net	42	(145)	120	(600)
Vehicle depreciation and lease charges, net	$ 806	$ 517	$ 2,175	$ 1,157

Amount of expense for allocation of cost of tangible asset over its useful life directly used in production of good and rendering of service.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(2))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483621/220-10-S99-2

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 360
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482099/360-10-50-1

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