Basis of Presentation (Disaggregated Revenue in Basis of Presentation) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Disaggregation of Revenue [Line Items]
Revenues	$ 3,480	$ 3,564	$ 9,079	$ 9,244
Avis
Disaggregation of Revenue [Line Items]
Revenues	2,011	2,043	5,218	5,206
Budget
Disaggregation of Revenue [Line Items]
Revenues	1,263	1,314	3,301	3,471
Other
Disaggregation of Revenue [Line Items]
Revenues	206	207	560	567
Americas
Disaggregation of Revenue [Line Items]
Revenues	2,640	2,736	6,994	7,180
Europe, Middle East and Africa
Disaggregation of Revenue [Line Items]
Revenues	689	672	1,615	1,582
Asia and Australasia
Disaggregation of Revenue [Line Items]
Revenues	$ 151	$ 156	$ 470	$ 482