Segment Information - Schedule of Segment Assets (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2026	Dec. 31, 2025
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment additions	$ 41	$ 218
Assets exclusive of assets under vehicle programs	10,464	10,306
Assets under vehicle programs	20,139	20,951
Net long-lived assets	2,481	2,466
Americas
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment additions	14	79
Assets exclusive of assets under vehicle programs	7,281	7,070
Assets under vehicle programs	16,371	17,312
Net long-lived assets	1,497	1,470
International
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment additions	6	36
Assets exclusive of assets under vehicle programs	2,906	2,951
Assets under vehicle programs	3,768	3,639
Net long-lived assets	789	805
Unallocated Assets
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment additions	21	103
Assets exclusive of assets under vehicle programs	277	285
Assets under vehicle programs	0	0
Net long-lived assets	$ 195	$ 191