| 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 | alowence for loan losses/ sums receivable on account of net credit card activity/Unaudited | boi_met:pi1223 | num:percentItemType | instant | N/A | N/A | boi_CS:x2 | N/A | boi_RP:x19 | N/A |
| 8.2 | alowence for loan losses/ sums receivable on account of net credit card activity/Audited | boi_met:pi1223 | num:percentItemType | instant | N/A | N/A | boi_CS:x2 | N/A | boi_RP:x24 | N/A |
| 9.1 | Impaired debts or debts 90 days or more in arrears / sums receivable on account of net credit card activity/Unaudited | boi_met:pi1224 | num:percentItemType | instant | N/A | N/A | boi_CS:x2 | N/A | boi_RP:x19 | N/A |
| 9.2 | Impaired debts or debts 90 days or more in arrears / sums receivable on account of net credit card activity/Audited | boi_met:pi1224 | 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 |
| 19.1 | 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 |
| 19.2 | 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 |
| 20.1 | 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 |
| 20.2 | 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 |
| 21.1 | Securities/Unaudited | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x29 | boi_RP:x19 | N/A |
| 21.2 | Securities/Audited | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x29 | boi_RP:x24 | N/A |
| 22.1 | Sums receivable on account of credit card activity, net/Unaudited | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x8 | boi_RP:x19 | boi_SE:x89 |
| 22.2 | Sums receivable on account of credit card activity, net/Audited | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x8 | boi_RP:x24 | boi_SE:x89 |
| 23.1 | 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 |
| 23.2 | 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 |
| 24.1 | Credit from banking corporations/Unaudited | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x2 | N/A | boi_CS:x2 | boi_MC:x17 | boi_RP:x19 | boi_SE:x1 |
| 24.2 | Credit from banking corporations/Audited | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x2 | N/A | boi_CS:x2 | boi_MC:x17 | boi_RP:x24 | boi_SE:x1 |
| 25.1 | Sums payable on account of credit card activity/Unaudited | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x2 | N/A | boi_CS:x2 | boi_MC:x17 | boi_RP:x19 | boi_SE:x89 |
| 25.2 | Sums payable on account of credit card activity/Audited | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x2 | N/A | boi_CS:x2 | boi_MC:x17 | boi_RP:x24 | boi_SE:x89 |
| 26.1 | Equity attributed to shareholders in credit card company/Unaudited | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x3 | boi_CN:x1 | boi_CS:x2 | boi_MC:x2 | boi_RP:x19 | N/A |
| 26.2 | Equity attributed to shareholders in credit card company/Audited | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x3 | boi_CN:x1 | boi_CS:x2 | boi_MC:x2 | boi_RP:x24 | N/A |
| r16.1 | Additional data/Unaudited | | | | N/A | N/A | boi_CS:x2 | N/A | boi_RP:x19 | N/A |
| r16.2 | Additional data/Audited | | | | N/A | N/A | boi_CS:x2 | N/A | boi_RP:x24 | N/A |
| 27.1 | Share price/Unaudited | boi_met:mi1184 | xbrli:monetaryItemType | instant | N/A | N/A | boi_CS:x2 | N/A | boi_RP:x19 | N/A |
| 27.2 | Share price/Audited | boi_met:mi1184 | xbrli:monetaryItemType | instant | N/A | N/A | boi_CS:x2 | N/A | boi_RP:x24 | N/A |