Summary of Changes to Restructuring-Related Liabilities (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restructuring Cost and Reserve [Line Items]
Balance, beginning	$ 6	$ 11	$ 17
Restructuring expense	(63)	(29)	(18)
Balance, ending	4	6	11
Americas
Restructuring Cost and Reserve [Line Items]
Balance, beginning	1	1	4
Balance, ending	1	1	1
International
Restructuring Cost and Reserve [Line Items]
Balance, beginning	5	10	13
Balance, ending	3	5	10
Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Balance, beginning	5	10	14
Balance, ending	4	5	10
Facility Closing [Member]
Restructuring Cost and Reserve [Line Items]
Balance, beginning	1	1	3
Balance, ending	0	1	1
Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Balance, beginning	0	0	0
Balance, ending	0	0	0
2011 Avis Europe Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense		1
Cash payment/utilization		(1)	(9)
2011 Avis Europe Restructuring [Member] | Americas
Restructuring Cost and Reserve [Line Items]
Restructuring expense		0
Cash payment/utilization		0	(1)
2011 Avis Europe Restructuring [Member] | International
Restructuring Cost and Reserve [Line Items]
Restructuring expense		1
Cash payment/utilization		(1)	(8)
2011 Avis Europe Restructuring [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense		1
Cash payment/utilization		(1)	(7)
2011 Avis Europe Restructuring [Member] | Facility Closing [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense		0
Cash payment/utilization		0	(2)
2011 Avis Europe Restructuring [Member] | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense		0
Cash payment/utilization		0	0
2018 Truck Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	(5)
Cash payment/utilization	(5)
2018 Truck Restructuring [Member] | Americas
Restructuring Cost and Reserve [Line Items]
Restructuring expense	(5)
Cash payment/utilization	(5)
2018 Truck Restructuring [Member] | International
Restructuring Cost and Reserve [Line Items]
Restructuring expense	0
Cash payment/utilization	0
2018 Truck Restructuring [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	(1)
Cash payment/utilization	(1)
2018 Truck Restructuring [Member] | Facility Closing [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	0
Cash payment/utilization	0
2018 Truck Restructuring [Member] | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	(4)
Cash payment/utilization	(4)
T17 Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	(35)
Cash payment/utilization	(33)
T17 Restructuring [Member] | Americas
Restructuring Cost and Reserve [Line Items]
Restructuring expense	(25)
Cash payment/utilization	(24)
T17 Restructuring [Member] | International
Restructuring Cost and Reserve [Line Items]
Restructuring expense	(10)
Cash payment/utilization	(9)
T17 Restructuring [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	(20)
Cash payment/utilization	(17)
T17 Restructuring [Member] | Facility Closing [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	0
Cash payment/utilization	(1)
T17 Restructuring [Member] | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	(15)
Cash payment/utilization	(15)
2014 T15 Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense		(21)	(9)
Cash payment/utilization	(3)	(18)	(12)
2014 T15 Restructuring [Member] | Americas
Restructuring Cost and Reserve [Line Items]
Restructuring expense		(11)	(6)
Cash payment/utilization	(1)	(11)	(8)
2014 T15 Restructuring [Member] | International
Restructuring Cost and Reserve [Line Items]
Restructuring expense		(10)	(3)
Cash payment/utilization	(2)	(7)	(4)
2014 T15 Restructuring [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense		(15)	(9)
Cash payment/utilization	(3)	(12)	(12)
2014 T15 Restructuring [Member] | Facility Closing [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense		(1)	0
Cash payment/utilization	0	(1)	0
2014 T15 Restructuring [Member] | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense		(5)	0
Cash payment/utilization	0	(5)	0
2015 Acquisition Integration [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense		(9)	(9)
Cash payment/utilization	(1)	(15)	(3)
2015 Acquisition Integration [Member] | Americas
Restructuring Cost and Reserve [Line Items]
Restructuring expense		0	(1)
Cash payment/utilization	0	0	(1)
2015 Acquisition Integration [Member] | International
Restructuring Cost and Reserve [Line Items]
Restructuring expense		(9)	(8)
Cash payment/utilization	(1)	(15)	(2)
2015 Acquisition Integration [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense		(9)	(9)
Cash payment/utilization	(1)	(15)	(3)
2015 Acquisition Integration [Member] | Facility Closing [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense		0	0
Cash payment/utilization	0	0	0
2015 Acquisition Integration [Member] | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense		0	0
Cash payment/utilization	$ 0	$ 0	$ 0