Leases Lessor (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Lessor, Lease, Description [Line Items]
Operating Lease, Lease Income	$ 2,713	$ 6,907
Americas [Member]
Lessor, Lease, Description [Line Items]
Operating Lease, Lease Income	1,856	4,792
EMEA [Member]
Lessor, Lease, Description [Line Items]
Operating Lease, Lease Income	717	1,684
Asia and Australasia [Member]
Lessor, Lease, Description [Line Items]
Operating Lease, Lease Income	140	431
Avis [Member]
Lessor, Lease, Description [Line Items]
Operating Lease, Lease Income	1,559	3,953
Budget [Member]
Lessor, Lease, Description [Line Items]
Operating Lease, Lease Income	935	2,379
Other Brands [Member]
Lessor, Lease, Description [Line Items]
Operating Lease, Lease Income	$ 219	$ 575