Basis of Presentation (Disaggregated Revenue in Basis of Presentation) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Disaggregation of Revenue [Line Items]
Revenues	$ 2,557	$ 2,432
Avis
Disaggregation of Revenue [Line Items]
Revenues	1,415	1,281
Budget
Disaggregation of Revenue [Line Items]
Revenues	977	982
Other
Disaggregation of Revenue [Line Items]
Revenues	165	169
Americas
Disaggregation of Revenue [Line Items]
Revenues	2,016	2,000
Europe, Middle East and Africa
Disaggregation of Revenue [Line Items]
Revenues	367	324
Asia and Australasia
Disaggregation of Revenue [Line Items]
Revenues	$ 174	$ 108