Segment Information (Schedule of Segment Assets) (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2025	Dec. 31, 2024
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment additions	$ 85	$ 202
Assets exclusive of assets under vehicle programs	10,157	9,668
Assets under vehicle programs	22,214	19,373
Net long-lived assets	2,446	2,369
Americas
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment additions	28	109
Assets exclusive of assets under vehicle programs	6,788	6,785
Assets under vehicle programs	17,938	16,058
Net long-lived assets	1,451	1,474
International
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment additions	14	40
Assets exclusive of assets under vehicle programs	3,040	2,539
Assets under vehicle programs	4,276	3,315
Net long-lived assets	803	733
Unallocated Assets
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment additions	43	53
Assets exclusive of assets under vehicle programs	329	344
Assets under vehicle programs	0	0
Net long-lived assets	$ 192	$ 162