Restructuring (Narrative) (Detail) $ in Millions	3 Months Ended
Mar. 31, 2020 USD ($) Employee	Mar. 31, 2019 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 44	$ 21
2020 Optimization [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 26
Restructuring and Related Cost, Expected Number of Positions Eliminated \| Employee	585
Restructuring and Related Cost, Number of Positions Eliminated \| Employee	450
Restructuring and Related Cost, Expected Cost Remaining	$ 15
Brazil Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 1
Restructuring and Related Cost, Number of Positions Eliminated \| Employee	20
Restructuring and Related Cost, Expected Cost Remaining	$ 7

Amount of expected cost remaining for the specified restructuring cost.

No definition available.

Name:	us-gaap_RestructuringAndRelatedCostExpectedCostRemaining1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The expected number of positions to be eliminated as a result of restructuring activities.

+ References

No definition available.

+ Details

Name:	us-gaap_RestructuringAndRelatedCostExpectedNumberOfPositionsEliminated
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of positions eliminated during the period as a result of restructuring activities.

+ References

No definition available.

+ Details

Name:	us-gaap_RestructuringAndRelatedCostNumberOfPositionsEliminated
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 5.P.3)
-URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140864-122747

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 5.P.4(b))
-URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140904-122747

+ Details

Name:	us-gaap_RestructuringCharges
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_RestructuringCostAndReserveLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_RestructuringPlanAxis=car_A2020OptimizationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestructuringPlanAxis=car_BrazilRestructuringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: