Financial assets at fair value through other comprehensive income - Equity instruments FVOCI (Detail) - ARS ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Disclosure of investments in equity instruments fvoci [Line Items]
Total equity instruments FVOCI	$ 28,499	$ 37,260
Banco Latinoaméricano de Exportaciones S.A. [member]
Disclosure of investments in equity instruments fvoci [Line Items]
Total equity instruments FVOCI	27,216	35,921
Others [member]
Disclosure of investments in equity instruments fvoci [Line Items]
Total equity instruments FVOCI	1,283	1,339
TOTAL
Disclosure of investments in equity instruments fvoci [Line Items]
Total equity instruments FVOCI	$ 28,499	$ 37,260

The amount of instruments held by the entity that provide evidence of a residual interest in the assets of another entity after deducting all of its liabilities at fair value through other comprehensive income.

No definition available.

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