Unrecognized Tax Benefits Additional Information (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes [Line Items]
Unrecognized tax benefits, non-current income taxes payable	$ 41	$ 46
Unrecognized Tax Benefits, Interest on Income Taxes Accrued	29	26
Unrecognized Tax Benefits	$ 61	63	$ 59	$ 56
Non Avis Budget Car Rental Tax Contingencies
Income Taxes [Line Items]
Unrecognized Tax Benefits		$ 13