Basis of Presentation (Disaggregated Revenue in Basis of Presentation) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Disaggregation of Revenue [Line Items]
Revenues	$ 3,244	$ 2,371	$ 5,676	$ 3,743
Avis
Disaggregation of Revenue [Line Items]
Revenues	1,753	1,204	3,034	1,921
Budget
Disaggregation of Revenue [Line Items]
Revenues	1,284	985	2,266	1,509
Other
Disaggregation of Revenue [Line Items]
Revenues	207	182	376	313
Americas
Disaggregation of Revenue [Line Items]
Revenues	2,567	1,974	4,567	3,054
Europe, Middle East and Africa
Disaggregation of Revenue [Line Items]
Revenues	525	281	849	484
Asia and Australasia
Disaggregation of Revenue [Line Items]
Revenues	$ 152	$ 116	$ 260	$ 205