Leases (Lessor) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Lessor, Lease, Description [Line Items]
Total lease revenues	$ 2,513	$ 2,398
Avis
Lessor, Lease, Description [Line Items]
Total lease revenues	1,388	1,261
Budget
Lessor, Lease, Description [Line Items]
Total lease revenues	964	972
Other
Lessor, Lease, Description [Line Items]
Total lease revenues	161	165
Americas
Lessor, Lease, Description [Line Items]
Total lease revenues	1,995	1,985
Europe, Middle East and Africa
Lessor, Lease, Description [Line Items]
Total lease revenues	349	309
Asia and Australasia
Lessor, Lease, Description [Line Items]
Total lease revenues	$ 169	$ 104