Basis of Presentation (Disaggregated Revenue in Basis of Presentation) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Disaggregation of Revenue [Line Items]
Revenues	$ 3,547	$ 3,001	$ 9,223	$ 6,744
Avis
Disaggregation of Revenue [Line Items]
Revenues	1,958	1,588	4,992	3,509
Budget
Disaggregation of Revenue [Line Items]
Revenues	1,371	1,198	3,637	2,707
Other
Disaggregation of Revenue [Line Items]
Revenues	218	215	594	528
Americas
Disaggregation of Revenue [Line Items]
Revenues	2,703	2,403	7,270	5,457
Europe, Middle East and Africa
Disaggregation of Revenue [Line Items]
Revenues	678	527	1,527	1,011
Asia and Australasia
Disaggregation of Revenue [Line Items]
Revenues	$ 166	$ 71	$ 426	$ 276