Summary of Significant Accounting Policies - Revenue (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Disaggregation of Revenue [Line Items]
Revenues	$ 11,652	$ 11,789	$ 12,008
Avis
Disaggregation of Revenue [Line Items]
Revenues	6,603	6,775	6,779
Budget
Disaggregation of Revenue [Line Items]
Revenues	4,325	4,271	4,478
Other
Disaggregation of Revenue [Line Items]
Revenues	724	743	751
Americas
Disaggregation of Revenue [Line Items]
Revenues	8,900	9,111	9,347
Europe, Middle East and Africa
Disaggregation of Revenue [Line Items]
Revenues	2,117	2,045	2,014
Asia and Australasia
Disaggregation of Revenue [Line Items]
Revenues	$ 635	$ 633	$ 647