Leases - Lessor (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Total lease revenues	$ 11,821	$ 11,829	$ 9,186
Operating Lease, Lease Income, Statement of Income or Comprehensive Income [Extensible Enumeration]	Revenues	Revenues	Revenues
Avis
Disaggregation of Revenue [Line Items]
Total lease revenues	$ 6,660	$ 6,420	$ 4,828
Budget
Disaggregation of Revenue [Line Items]
Total lease revenues	4,425	4,650	3,674
Other
Disaggregation of Revenue [Line Items]
Total lease revenues	736	759	684
Americas
Disaggregation of Revenue [Line Items]
Total lease revenues	9,261	9,401	7,501
Europe, Middle East and Africa
Disaggregation of Revenue [Line Items]
Total lease revenues	1,932	1,852	1,343
Asia and Australasia
Disaggregation of Revenue [Line Items]
Total lease revenues	$ 628	$ 576	$ 342