Segment Information (Summary of Segments Information) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Segment Reporting Information [Line Items]
Revenues	$ 3,123	$ 3,244	$ 5,680	$ 5,676
Adjusted EBITDA	737	1,205	1,272	2,015
Less:
Non-vehicle related depreciation and amortization	52	51	108	109
Interest expense	68	64	141	117
Restructuring and other related charges	1	6	5	14
Transaction-related costs, net	0	1	0	1
Other (income) expense, net	4	0	2	0
COVID-19 charges	0	(2)	0	(9)
Legal matters, net	5	0	5	1
Net income	598	1,083	995	1,778
Operating Expense | Cloud Computing Costs
Less:
Cloud computing costs	9	2	16	4
Corporate and Other
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Adjusted EBITDA	(20)	(19)	(51)	(42)
Americas | Geographical
Segment Reporting Information [Line Items]
Revenues	2,428	2,567	4,444	4,567
Adjusted EBITDA	631	1,041	1,147	1,851
International | Geographical
Segment Reporting Information [Line Items]
Revenues	695	677	1,236	1,109
Adjusted EBITDA	$ 126	$ 183	$ 176	$ 206