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Functional and presentation currency and hyperinflationary accounting - Additional Information (Detail) | 12 Months Ended
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Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Hyperinflationary Accounting [Abstract] |  |  |
General Price index | 53.83% | 47.65% | 24.80%

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- Definition Hyperinflationary accounting. + References No definition available. + Details
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- Definition Increase in general Price index. + References No definition available. + Details
Name: | bbar_IncreaseInGeneralPriceIndex
Namespace Prefix: | bbar_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration