Basis of Presentation (Disaggregated Revenue in Basis of Presentation) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Disaggregation of Revenue [Line Items]
Revenues	$ 3,564	$ 3,547	$ 9,244	$ 9,223
Avis
Disaggregation of Revenue [Line Items]
Revenues	2,043	1,958	5,206	4,992
Budget
Disaggregation of Revenue [Line Items]
Revenues	1,314	1,371	3,471	3,637
Other
Disaggregation of Revenue [Line Items]
Revenues	207	218	567	594
Americas
Disaggregation of Revenue [Line Items]
Revenues	2,736	2,703	7,180	7,270
Europe, Middle East and Africa
Disaggregation of Revenue [Line Items]
Revenues	672	678	1,582	1,527
Asia and Australasia
Disaggregation of Revenue [Line Items]
Revenues	$ 156	$ 166	$ 482	$ 426