Stockholders' Equity (Components Of Other Comprehensive Income) (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Equity [Abstract]
Net income (loss)	$ 674	$ 45	$ 902	$ (594)
Less: net loss attributable to non-controlling interests	1	0	1	0
Net income (loss) attributable to Avis Budget Group, Inc.	675	45	903	(594)
Other comprehensive income (loss):
Currency translation adjustments (net of tax of $(6), $12, $(15) and $12, respectively)	(23)	35	(22)	(9)
Net unrealized gain (loss) on cash flow hedges (net of tax of $(2), $3, $(9) and $12, respectively)	6	(7)	27	(33)
Minimum pension liability adjustment (net of tax of $(1), $(1), $(1) and $(1), respectively)	2	1	6	5
Other comprehensive income (loss)	(15)	29	11	(37)
Comprehensive income (loss) attributable to Avis Budget Group, Inc.	660	74	914	(631)
Currency translation adjustments, tax	(6)	12	(15)	12
Net unrealized gain (loss) on cash flow hedges, tax	(2)	3	(9)	12
Minimum pension liability adjustment, tax	$ (1)	$ (1)	$ (1)	$ (1)