Investment in Joint Ventures and Associates - Most Significant Investment in Joint Ventures and Associates (Details) - ARS ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
PSA Finance Arg Cia Financiera SA
Most Significant Investment in Joint Ventures and Associates
Assets of Joint Ventures and Associates		$ 6,321,185
Liabilities of Joint Ventures and Associates		4,972,235
Profit of Joint Ventures and Associates		229,683
Equity of Joint Ventures and Associates		$ 1,348,950
Ownership Interest		50.00%
Rombo Cia Financiera SA
Most Significant Investment in Joint Ventures and Associates
Assets of Joint Ventures and Associates	$ 7,934,042	$ 13,875,829
Liabilities of Joint Ventures and Associates	6,289,825	11,920,150
Profit of Joint Ventures and Associates	290,597	103,017
Equity of Joint Ventures and Associates	$ 1,644,217	$ 1,955,679
Ownership Interest	40.00%	40.00%
Volkswagen Financial Services Cia Financiera SA
Most Significant Investment in Joint Ventures and Associates
Assets of Joint Ventures and Associates		$ 12,377,624
Liabilities of Joint Ventures and Associates		10,448,390
Profit of Joint Ventures and Associates		379,314
Equity of Joint Ventures and Associates		$ 1,929,234
Ownership Interest		51.00%

The amount of assets related to the most significant investment in joint ventures and associates.

No definition available.

Name:	bbar_AssetsOfJointVenturesAndAssociates
Namespace Prefix:	bbar_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Disclosure of most significant investments in associates.

+ References

No definition available.

+ Details

Name:	bbar_DisclosureOfMostSignificantInvestmentsInAssociatesLineItems
Namespace Prefix:	bbar_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The equity related to the most significant investment in joint ventures and associates.

+ References

No definition available.

+ Details

Name:	bbar_EquityOfJointVenturesAndAssociates
Namespace Prefix:	bbar_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of liabilities related to the most significant investment in joint ventures and associates.

+ References

No definition available.

+ Details

Name:	bbar_LiabilitiesOfJointVenturesAndAssociates
Namespace Prefix:	bbar_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The profit related to the most significant investment in joint ventures and associates.

+ References

No definition available.

+ Details

Name:	bbar_ProfitOfJointVenturesAndAssociate
Namespace Prefix:	bbar_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The proportion of ownership interest in a subsidiary attributable to the entity. [Refer: Subsidiaries [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 27
-IssueDate 2019-01-01
-Paragraph 17
-Subparagraph b
-Clause iii
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=27&code=ifrs-tx-2019-en-r&anchor=para_17_b_iii&doctype=Standard
-URIDate 2019-03-27

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 27
-IssueDate 2019-01-01
-Paragraph 16
-Subparagraph b
-Clause iii
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=27&code=ifrs-tx-2019-en-r&anchor=para_16_b_iii&doctype=Standard
-URIDate 2019-03-27

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 12
-IssueDate 2019-01-01
-Paragraph 19B
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2019-en-r&anchor=para_19B_c&doctype=Standard
-URIDate 2019-03-27

+ Details

Name:	ifrs-full_ProportionOfOwnershipInterestInSubsidiary
Namespace Prefix:	ifrs-full_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	bbar_SignificantInvestmentsInAssociates1Axis=bbar_PSAFinanceArgCiaFinancieraSAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	bbar_SignificantInvestmentsInAssociates1Axis=bbar_RomboCiaFinancieraSAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	bbar_SignificantInvestmentsInAssociates1Axis=bbar_VolkswagenFinancialServicesCompaaFinancieraSaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: