Restructuring - Additional Information (Detail) $ in Millions	12 Months Ended			15 Months Ended	24 Months Ended	60 Months Ended
	Dec. 31, 2018 USD ($) Employee	Dec. 31, 2017 USD ($) Employee	Dec. 31, 2016 USD ($)	Dec. 31, 2018 Employee	Dec. 31, 2018 Employee	Dec. 31, 2018 Employee
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 22	$ 63	$ 29
2018 Truck Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	5	5
Restructuring and Related Cost, Expected Number of Positions Eliminated | Employee				25
Workforce Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 13
Restructuring and Related Cost, Expected Number of Positions Eliminated | Employee	190
Restructuring and Related Cost, Number of Positions Eliminated | Employee	180
2015 Acquisition Integration [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			9
T17 Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 2	$ 35
Restructuring and Related Cost, Expected Number of Positions Eliminated | Employee	680
Restructuring and Related Cost, Number of Positions Eliminated | Employee					675
2014 T15 Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 1		21
Restructuring and Related Cost, Expected Number of Positions Eliminated | Employee		615
Restructuring and Related Cost, Number of Positions Eliminated | Employee						990
2011 Avis Europe Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			(1)
Americas | 2018 Truck Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	5	$ 5
Americas | Workforce Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	4
Americas | 2015 Acquisition Integration [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			0
Americas | T17 Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	2	25
Americas | 2014 T15 Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	0		11
Americas | 2011 Avis Europe Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			0
International | 2018 Truck Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	0	0
International | Workforce Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	9
International | 2015 Acquisition Integration [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			9
International | T17 Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	0	$ 10
International | 2014 T15 Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 1		10
International | 2011 Avis Europe Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			$ (1)