Restructuring - Termination Charges (Details) - Restructuring Plan, Impact of COVID-19 - Employee Severance - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2020
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 37	$ 37
Corporate, Non-Segment
Restructuring Cost and Reserve [Line Items]
Restructuring costs	3	3
U.S. Rental Car
Restructuring Cost and Reserve [Line Items]
Restructuring costs	34	34
Direct Vehicle and Operating
Restructuring Cost and Reserve [Line Items]
Restructuring costs	25	25
Selling, General and Administrative Expenses
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 12	$ 12