Basis of Presentation (Disaggregated Revenue in Basis of Presentation) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Disaggregation of Revenue [Line Items]
Revenues	$ 3,123	$ 3,244	$ 5,680	$ 5,676
Avis
Disaggregation of Revenue [Line Items]
Revenues	1,748	1,753	3,163	3,034
Budget
Disaggregation of Revenue [Line Items]
Revenues	1,180	1,284	2,157	2,266
Other
Disaggregation of Revenue [Line Items]
Revenues	195	207	360	376
Americas
Disaggregation of Revenue [Line Items]
Revenues	2,428	2,567	4,444	4,567
Europe, Middle East and Africa
Disaggregation of Revenue [Line Items]
Revenues	543	525	910	849
Asia and Australasia
Disaggregation of Revenue [Line Items]
Revenues	$ 152	$ 152	$ 326	$ 260