Segment Information - Summary of Segments Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Segment Reporting Information [Line Items]
Revenues	$ 12,008	$ 11,994	$ 9,313
Vehicle depreciation and lease charges, net	1,739	828	1,197
Vehicle interest, net	736	402	313
Adjusted EBITDA	2,490	4,133	2,411
Non-vehicle related depreciation and amortization	216	225	272
Assets exclusive of assets under vehicle programs	9,590	8,499	8,581
Assets under vehicle programs	22,979	17,428	14,019
Property and equipment additions	273	246	108
Americas
Segment Reporting Information [Line Items]
Revenues	9,347	9,474	7,557
Vehicle depreciation and lease charges, net	1,215	414	851
Vehicle interest, net	617	348	258
Adjusted EBITDA	2,196	3,660	2,364
Non-vehicle related depreciation and amortization	147	141	178
Assets exclusive of assets under vehicle programs	6,533	5,798	5,746
Assets under vehicle programs	19,285	14,269	11,437
Property and equipment additions	126	117	74
International
Segment Reporting Information [Line Items]
Revenues	2,661	2,520	1,756
Vehicle depreciation and lease charges, net	524	414	346
Vehicle interest, net	119	54	55
Adjusted EBITDA	400	560	118
Non-vehicle related depreciation and amortization	68	66	84
Assets exclusive of assets under vehicle programs	2,633	2,402	2,716
Assets under vehicle programs	3,694	3,159	2,582
Property and equipment additions	44	33	26
Corporate and Other
Segment Reporting Information [Line Items]
Revenues	0	0	0
Vehicle depreciation and lease charges, net	0	0	0
Vehicle interest, net	0	0	0
Adjusted EBITDA	(106)	(87)	(71)
Non-vehicle related depreciation and amortization	1	18	10
Assets exclusive of assets under vehicle programs	424	299	119
Assets under vehicle programs	0	0	0
Property and equipment additions	$ 103	$ 96	$ 8