Segment Information - Schedule of Segments Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Segment Reporting Information [Line Items]
Revenues	$ 2,530	$ 2,430
Significant segment expenses:
Operating	1,422	1,353
Vehicle depreciation and lease charges, net	664	1,055
Selling, general and administrative	341	308
Vehicle interest, net	229	210
Reconciliation of reportable segment Adjusted EBITDA to loss before income taxes:
Non-vehicle related depreciation and amortization	58	56
Other fleet charges		390
Restructuring and other related charges	35	22
Transaction-related costs, net	6	0
Other (income) expense, net	6	6
Loss before income taxes	(340)	(677)
Operating Segments
Segment Reporting Information [Line Items]
Revenues	2,530	2,430
Significant segment expenses:
Reportable segment Adjusted EBITDA	(93)	(70)
Reconciliation of reportable segment Adjusted EBITDA to loss before income taxes:
Non-vehicle related depreciation and amortization	58	55
Interest expense	5	2
Other fleet charges	0	390
Restructuring and other related charges	35	22
Transaction-related costs, net	4	0
Other (income) expense, net	6	6
Other segment expenses	1	1
Operating Segments | Americas
Segment Reporting Information [Line Items]
Revenues	1,962	1,907
Significant segment expenses:
Operating	1,090	1,064
Vehicle depreciation and lease charges, net	532	533
Selling, general and administrative	223	200
Vehicle interest, net	197	177
Reportable segment Adjusted EBITDA	(80)	(67)
Operating Segments | International
Segment Reporting Information [Line Items]
Revenues	568	523
Significant segment expenses:
Operating	316	274
Vehicle depreciation and lease charges, net	132	132
Selling, general and administrative	101	87
Vehicle interest, net	32	33
Reportable segment Adjusted EBITDA	(13)	(3)
Corporate and Other
Reconciliation of reportable segment Adjusted EBITDA to loss before income taxes:
Corporate and other	138	131
Interest expense	$ 104	$ 95