Segment Information (Schedule of Segment Assets) (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2025	Dec. 31, 2024
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment additions	$ 136	$ 202
Assets exclusive of assets under vehicle programs	10,780	9,668
Assets under vehicle programs	21,738	19,373
Net long-lived assets	2,431	2,369
Americas
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment additions	44	109
Assets exclusive of assets under vehicle programs	7,394	6,785
Assets under vehicle programs	17,504	16,058
Net long-lived assets	1,438	1,474
International
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment additions	23	40
Assets exclusive of assets under vehicle programs	3,066	2,539
Assets under vehicle programs	4,234	3,315
Net long-lived assets	793	733
Unallocated Assets
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment additions	69	53
Assets exclusive of assets under vehicle programs	320	344
Assets under vehicle programs	0	0
Net long-lived assets	$ 200	$ 162