| r0.1 | label_boi_a2/Unaudited | | | | N/A | N/A | boi_CS:x2 | N/A | boi_RP:x19 | N/A |
| r0.2 | label_boi_a2/Audited | | | | N/A | N/A | boi_CS:x2 | N/A | boi_RP:x24 | N/A |
| 3.1 | Tier 1 equity capital / risk components ratio/Unaudited | boi_met:pi37 | num:percentItemType | instant | N/A | N/A | boi_CS:x2 | N/A | boi_RP:x19 | N/A |
| 3.2 | Tier 1 equity capital / risk components ratio/Audited | boi_met:pi37 | num:percentItemType | instant | N/A | N/A | boi_CS:x2 | N/A | boi_RP:x24 | N/A |
| 4.1 | Leverage ratio/Unaudited | boi_met:pi903 | num:percentItemType | instant | N/A | N/A | boi_CS:x2 | N/A | boi_RP:x19 | N/A |
| 4.2 | Leverage ratio/Audited | boi_met:pi903 | num:percentItemType | instant | N/A | N/A | boi_CS:x2 | N/A | boi_RP:x24 | N/A |
| 5.1 | Liquidity coverage ratio/Unaudited | boi_met:ri793 | xbrli:decimalItemType | instant | N/A | N/A | boi_CS:x2 | N/A | boi_RP:x19 | N/A |
| 5.2 | Liquidity coverage ratio/Audited | boi_met:ri793 | xbrli:decimalItemType | instant | N/A | N/A | boi_CS:x2 | N/A | boi_RP:x24 | N/A |
| r4.1 | Main credit quality indices/Unaudited | | | | N/A | N/A | boi_CS:x2 | N/A | boi_RP:x19 | N/A |
| r4.2 | Main credit quality indices/Audited | | | | N/A | N/A | boi_CS:x2 | N/A | boi_RP:x24 | N/A |
| 8.1 | Loan loss provisions as a share of credit to the public/Unaudited | boi_met:pi1181 | num:percentItemType | instant | N/A | N/A | boi_CS:x2 | N/A | boi_RP:x19 | N/A |
| 8.2 | Loan loss provisions as a share of credit to the public/Audited | boi_met:pi1181 | num:percentItemType | instant | N/A | N/A | boi_CS:x2 | N/A | boi_RP:x24 | N/A |
| 9.1 | Nonperforming debts or debts 90 days or more in arrears as a share of credit to the public/Unaudited | boi_met:pi1339 | num:percentItemType | instant | N/A | N/A | boi_CS:x2 | N/A | boi_RP:x19 | N/A |
| 9.2 | Nonperforming debts or debts 90 days or more in arrears as a share of credit to the public/Audited | boi_met:pi1339 | num:percentItemType | instant | N/A | N/A | boi_CS:x2 | N/A | boi_RP:x24 | N/A |
| r7.1 | Maindata from balancesheet/Unaudited | boi_met:mi1 | xbrli:monetaryItemType | instant | N/A | N/A | boi_CS:x2 | N/A | boi_RP:x19 | N/A |
| r7.2 | Maindata from balancesheet/Audited | boi_met:mi1 | xbrli:monetaryItemType | instant | N/A | N/A | boi_CS:x2 | N/A | boi_RP:x24 | N/A |
| 20.1 | Total assets/Unaudited | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x1 | boi_RP:x19 | N/A |
| 20.2 | Total assets/Audited | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x1 | boi_RP:x24 | N/A |
| 21.1 | Cash and deposits with banks/Unaudited | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x9 | boi_RP:x19 | boi_SE:x1 |
| 21.2 | Cash and deposits with banks/Audited | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x9 | boi_RP:x24 | boi_SE:x1 |
| 22.1 | Securities/Unaudited | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x29 | boi_RP:x19 | N/A |
| 22.2 | Securities/Audited | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x29 | boi_RP:x24 | N/A |
| 23.1 | Credit to the public, net/Unaudited | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x8 | boi_RP:x19 | boi_SE:x16 |
| 23.2 | Credit to the public, net/Audited | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x8 | boi_RP:x24 | boi_SE:x16 |
| 24.1 | Total liabilities/Unaudited | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x2 | N/A | boi_CS:x2 | boi_MC:x3 | boi_RP:x19 | N/A |
| 24.2 | Total liabilities/Audited | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x2 | N/A | boi_CS:x2 | boi_MC:x3 | boi_RP:x24 | N/A |
| 25.1 | Deposits of the public/Unaudited | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x2 | N/A | boi_CS:x2 | boi_MC:x17 | boi_RP:x19 | boi_SE:x16 |
| 25.2 | Deposits of the public/Audited | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x2 | N/A | boi_CS:x2 | boi_MC:x17 | boi_RP:x24 | boi_SE:x16 |
| 26.1 | Deposits from banks/Unaudited | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x2 | N/A | boi_CS:x2 | boi_MC:x17 | boi_RP:x19 | boi_SE:x1 |
| 26.2 | Deposits from banks/Audited | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x2 | N/A | boi_CS:x2 | boi_MC:x17 | boi_RP:x24 | boi_SE:x1 |
| 27.1 | Debentures and subordinated notes/Unaudited | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x2 | N/A | boi_CS:x2 | boi_MC:x15 | boi_RP:x19 | N/A |
| 27.2 | Debentures and subordinated notes/Audited | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x2 | N/A | boi_CS:x2 | boi_MC:x15 | boi_RP:x24 | N/A |
| 28.1 | Equity capital attributed to shareholders of the banking corporation/Unaudited | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x3 | boi_CN:x1 | boi_CS:x2 | boi_MC:x2 | boi_RP:x19 | N/A |
| 28.2 | Equity capital attributed to shareholders of the banking corporation/Audited | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x3 | boi_CN:x1 | boi_CS:x2 | boi_MC:x2 | boi_RP:x24 | N/A |
| r17.1 | Additional data/Unaudited | | | | N/A | N/A | boi_CS:x2 | N/A | boi_RP:x19 | N/A |
| r17.2 | Additional data/Audited | | | | N/A | N/A | boi_CS:x2 | N/A | boi_RP:x24 | N/A |
| 29.1 | Share price/Unaudited | boi_met:mi1184 | xbrli:monetaryItemType | instant | N/A | N/A | boi_CS:x2 | N/A | boi_RP:x19 | N/A |
| 29.2 | Share price/Audited | boi_met:mi1184 | xbrli:monetaryItemType | instant | N/A | N/A | boi_CS:x2 | N/A | boi_RP:x24 | N/A |