Segment Information (Summary of Segments Information) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Segment Reporting Information [Line Items]
Revenues	$ 3,564	$ 3,547	$ 9,244	$ 9,223
Adjusted EBITDA	907	1,460	2,179	3,475
Less:
Non-vehicle related depreciation and amortization	55	59	163	168
Interest expense	80	64	221	181
Early extinguishment of debt	1	0	1	0
Restructuring and other related charges	2	2	7	16
Transaction-related costs, net	3	0	3	1
Other (income) expense, net	1	(9)	3	(9)
COVID-19 charges			0	(9)
Legal matters, net			5	1
Net income	757	1,342	1,752	3,120
Operating Expense | Cloud Computing Costs
Less:
Cloud computing costs	8	2	24	6
Corporate and Other
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Adjusted EBITDA	(29)	(16)	(80)	(58)
Americas | Geographical
Segment Reporting Information [Line Items]
Revenues	2,736	2,703	7,180	7,270
Adjusted EBITDA	740	1,185	1,887	3,036
International | Geographical
Segment Reporting Information [Line Items]
Revenues	828	844	2,064	1,953
Adjusted EBITDA	$ 196	$ 291	$ 372	$ 497