Segment Information - Summary of Segments Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Revenues	$ 11,789	$ 12,008	$ 11,994
Significant segment expenses:
Operating	6,014	5,675	5,285
Vehicle depreciation and lease charges, net	2,976	1,739	828
Selling, general and administrative	1,352	1,408	1,348
Vehicle interest, net	941	736	402
Reconciliation of reportable segment Adjusted EBITDA to income (loss) before income taxes:
Non-vehicle related depreciation and amortization	237	216	225
Long-lived asset impairment and other related charges	2,470	0	0
Restructuring and other related charges	37	11	19
Transaction-related costs, net	3	5	8
Other (income) expense, net	9	3	(7)
Income (loss) before income taxes	(2,627)	1,914	3,636
Non-cash impairment	2,300	0	0
Impairment, long-lived asset, held-for-use	180	0	0
Interest expense	358	296	250
Early extinguishment of debt	(19)	(5)	0
Operating Segments
Segment Reporting Information [Line Items]
Revenues	11,789	12,008
Significant segment expenses:
Reportable segment Adjusted EBITDA	712	2,596	4,220
Reconciliation of reportable segment Adjusted EBITDA to income (loss) before income taxes:
Non-vehicle related depreciation and amortization	234	215	207
Interest expense related to corporate debt, net	4	(6)	3
Long-lived asset impairment and other related charges	2,470
Restructuring and other related charges	37	11	18
Transaction-related costs, net	3	3	8
Other (income) expense, net	9	3	(7)
Legal matters, net; cloud computing costs; and severe weather-related damages, net	77	10	(3)
Segment Reporting, Reconciling Item, Corporate Nonsegment
Reconciliation of reportable segment Adjusted EBITDA to income (loss) before income taxes:
Corporate and other	505	446	358
Interest expense	354	302	247
Early extinguishment of debt	19	5
Americas
Segment Reporting Information [Line Items]
Revenues			9,474
Americas | Operating Segments
Segment Reporting Information [Line Items]
Revenues	9,111	9,347
Significant segment expenses:
Operating	4,604	4,425	4,150
Vehicle depreciation and lease charges, net	2,301	1,215	414
Selling, general and administrative	868	894	902
Vehicle interest, net	787	617	348
Reportable segment Adjusted EBITDA	551	2,196	3,660
International
Segment Reporting Information [Line Items]
Revenues			2,520
International | Operating Segments
Segment Reporting Information [Line Items]
Revenues	2,678	2,661
Significant segment expenses:
Operating	1,279	1,209	1,114
Vehicle depreciation and lease charges, net	675	524	414
Selling, general and administrative	409	409	378
Vehicle interest, net	154	119	54
Reportable segment Adjusted EBITDA	$ 161	$ 400	$ 560