Leases Lessor (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Lessor, Lease, Description [Line Items]
Operating Lease, Lease Income	$ 2,304	$ 4,194
Americas [Member]
Lessor, Lease, Description [Line Items]
Operating Lease, Lease Income	1,617	2,936
EMEA [Member]
Lessor, Lease, Description [Line Items]
Operating Lease, Lease Income	553	967
Asia and Australasia [Member]
Lessor, Lease, Description [Line Items]
Operating Lease, Lease Income	134	291
Avis [Member]
Lessor, Lease, Description [Line Items]
Operating Lease, Lease Income	1,311	2,394
Budget [Member]
Lessor, Lease, Description [Line Items]
Operating Lease, Lease Income	804	1,444
Other Brands [Member]
Lessor, Lease, Description [Line Items]
Operating Lease, Lease Income	$ 189	$ 356