Segment Information - Summary of Segments Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Segment Reporting Information [Line Items]
Revenues	$ 11,652	$ 11,789	$ 12,008
Significant segment expenses:
Operating	5,857	6,014	5,675
Vehicle depreciation and lease charges, net	3,015	2,976	1,739
Selling, general and administrative	1,447	1,352	1,408
Vehicle interest, net	918	941	736
Reconciliation of reportable segment Adjusted EBITDA to income (loss) before income taxes:
Non-vehicle related depreciation and amortization	231	237	216
Long-lived asset impairment and other related charges	518	2,470	0
Other fleet charges	390
Restructuring and other related charges	131	37	11
Transaction-related costs, net	18	3	5
Other (income) expense, net	18	9	3
Income (loss) before income taxes	(929)	(2,627)	1,914
Non-cash impairment		2,300
Impairment, long-lived asset, held-for-use	0	180	0
Early extinguishment of debt	(6)	(19)	(5)
Operating Segments
Segment Reporting Information [Line Items]
Revenues	11,652	11,789
Significant segment expenses:
Reportable segment Adjusted EBITDA	842	712	2,596
Reconciliation of reportable segment Adjusted EBITDA to income (loss) before income taxes:
Non-vehicle related depreciation and amortization	229	234	215
Interest expense related to corporate debt, net:	11	4	(6)
Long-lived asset impairment and other related charges	518	2,470
Other fleet charges	390
Restructuring and other related charges	117	37	11
Transaction-related costs, net		3	3
Other (income) expense, net	18	9	3
Legal matters, net; cloud computing costs; and severe weather-related damages, net	(105)	77	10
Corporate and Other
Reconciliation of reportable segment Adjusted EBITDA to income (loss) before income taxes:
Corporate and other	593	505	446
Interest expense	411	354	302
Early extinguishment of debt	6	19	5
Americas
Segment Reporting Information [Line Items]
Revenues			9,347
Americas | Operating Segments
Segment Reporting Information [Line Items]
Revenues	8,900	9,111
Significant segment expenses:
Operating	4,598	4,604	4,425
Vehicle depreciation and lease charges, net	2,026	2,301	1,215
Selling, general and administrative	942	868	894
Vehicle interest, net	782	787	617
Reportable segment Adjusted EBITDA	552	551	2,196
International
Segment Reporting Information [Line Items]
Revenues			2,661
International | Operating Segments
Segment Reporting Information [Line Items]
Revenues	2,752	2,678
Significant segment expenses:
Operating	1,303	1,279	1,209
Vehicle depreciation and lease charges, net	599	675	524
Selling, general and administrative	424	409	409
Vehicle interest, net	136	154	119
Reportable segment Adjusted EBITDA	$ 290	$ 161	$ 400