| r0.1 | label_boi_a2/Basel III | | | | N/A | boi_CS:x2 | N/A | N/A | boi_RP:x24 | N/A |
| r1.1 | Capital for calculation of capital ratio/Basel III | boi_met:mi15 | xbrli:monetaryItemType | instant | boi_BC:x15 | boi_CS:x2 | N/A | N/A | boi_RP:x24 | N/A |
| 1.1 | Tier 1 equity capital, after supervisory reconciliations and subtractions/Basel III | boi_met:mi15 | xbrli:monetaryItemType | instant | boi_BC:x15 | boi_CS:x2 | N/A | boi_MC:x193 | boi_RP:x24 | N/A |
| 2.1 | Tier 1 capital, after subtractions/Basel III | boi_met:mi15 | xbrli:monetaryItemType | instant | boi_BC:x15 | boi_CS:x2 | N/A | boi_MC:x596 | boi_RP:x24 | N/A |
| 3.1 | Tier 2 capital, after subtractions/Basel III | boi_met:mi15 | xbrli:monetaryItemType | instant | boi_BC:x15 | boi_CS:x2 | N/A | boi_MC:x229 | boi_RP:x24 | N/A |
| 4.1 | Total capital/Basel III | boi_met:mi15 | xbrli:monetaryItemType | instant | boi_BC:x15 | boi_CS:x2 | N/A | boi_MC:x192 | boi_RP:x24 | N/A |
| r6.1 | Risk weighted asset balances/Basel III | boi_met:mi30 | xbrli:monetaryItemType | instant | boi_BC:x16 | boi_CS:x2 | N/A | N/A | boi_RP:x24 | N/A |
| 5.1 | Credit risk/Basel III | boi_met:mi30 | xbrli:monetaryItemType | instant | boi_BC:x16 | boi_CS:x2 | N/A | N/A | boi_RP:x24 | boi_RT:x21 |
| 6.1 | Market risk/Basel III | boi_met:mi30 | xbrli:monetaryItemType | instant | boi_BC:x16 | boi_CS:x2 | boi_MC:x57 | N/A | boi_RP:x24 | boi_RT:x3 |
| 7.1 | Operational risk/Basel III | boi_met:mi30 | xbrli:monetaryItemType | instant | boi_BC:x16 | boi_CS:x2 | N/A | N/A | boi_RP:x24 | boi_RT:x5 |
| 8.1 | Total risk weighted asset balances/Basel III | boi_met:mi30 | xbrli:monetaryItemType | instant | boi_BC:x16 | boi_CS:x2 | N/A | N/A | boi_RP:x24 | N/A |
| r11.1 | RVA ratios/Basel III | | | | N/A | boi_CS:x2 | N/A | N/A | boi_RP:x24 | N/A |
| 9.1 | Tier 1 equity capital / risk components ratio/Basel III | boi_met:pi37 | num:percentItemType | instant | N/A | boi_CS:x2 | N/A | N/A | boi_RP:x24 | N/A |
| 10.1 | Tier 1 capital / risk components ratio/Basel III | boi_met:pi267 | num:percentItemType | instant | N/A | boi_CS:x2 | N/A | N/A | boi_RP:x24 | N/A |
| 11.1 | Total capital / risk components ratio/Basel III | boi_met:pi38 | num:percentItemType | instant | N/A | boi_CS:x2 | N/A | N/A | boi_RP:x24 | N/A |
| 12.1 | Minimum equity capital ratio required by Supervisor of Banks/Basel III | boi_met:pi39 | num:percentItemType | instant | N/A | boi_CS:x2 | N/A | N/A | boi_RP:x24 | N/A |
| 13.1 | Total minimum capital ratio required by Supervisor of Banks/Basel III | boi_met:pi40 | num:percentItemType | instant | N/A | boi_CS:x2 | N/A | N/A | boi_RP:x24 | N/A |
| r17.1 | Capital components for purpose of calculating capital ratio/Basel III | boi_met:mi15 | xbrli:monetaryItemType | instant | boi_BC:x15 | boi_CS:x2 | N/A | N/A | boi_RP:x24 | N/A |
| r18.1 | Tier 1 capital/Basel III | boi_met:mi15 | xbrli:monetaryItemType | instant | boi_BC:x15 | boi_CS:x2 | N/A | N/A | boi_RP:x24 | N/A |
| r19.1 | Tier 1 equity capital/Basel III | boi_met:mi15 | xbrli:monetaryItemType | instant | boi_BC:x15 | boi_CS:x2 | N/A | N/A | boi_RP:x24 | N/A |
| 14.1 | Equity/Basel III | boi_met:mi15 | xbrli:monetaryItemType | instant | boi_BC:x15 | boi_CS:x2 | N/A | boi_MC:x578 | boi_RP:x24 | N/A |
| 15.1 | Differences between equity capital and Tier 1 equity capital/Basel III | boi_met:mi15 | xbrli:monetaryItemType | instant | boi_BC:x15 | boi_CS:x2 | N/A | boi_MC:x204 | boi_RP:x24 | N/A |
| 16.1 | Total tier 1 equity capital before supervisory reconciliations and subtractions/Basel III | boi_met:mi15 | xbrli:monetaryItemType | instant | boi_BC:x15 | boi_CS:x2 | N/A | boi_MC:x194 | boi_RP:x24 | N/A |
| r23.1 | Supervisory reconciliations and deductions/Basel III | boi_met:mi15 | xbrli:monetaryItemType | instant | boi_BC:x15 | boi_CS:x2 | N/A | N/A | boi_RP:x24 | N/A |
| 17.1 | Goodwill and intangible assets/Basel III | boi_met:mi15 | xbrli:monetaryItemType | instant | boi_BC:x15 | boi_CS:x2 | N/A | boi_MC:x206 | boi_RP:x24 | N/A |
| 18.1 | Deferred taxes receivable/Basel III | boi_met:mi15 | xbrli:monetaryItemType | instant | boi_BC:x15 | boi_CS:x2 | N/A | boi_MC:x579 | boi_RP:x24 | N/A |
| 19.1 | Investments in capital of unconsolidated financial corporations/Basel III | boi_met:mi15 | xbrli:monetaryItemType | instant | boi_BC:x15 | boi_CS:x2 | N/A | boi_MC:x580 | boi_RP:x24 | N/A |
| 20.1 | Other supervisory reconciliations and deductions - Tier 1 equity capital/Basel III | boi_met:mi15 | xbrli:monetaryItemType | instant | boi_BC:x15 | boi_CS:x2 | N/A | boi_MC:x581 | boi_RP:x24 | N/A |
| 21.1 | Total supervisory reconciliations and deductions - Tier 1 equity capital/Basel III | boi_met:mi15 | xbrli:monetaryItemType | instant | boi_BC:x15 | boi_CS:x2 | N/A | boi_MC:x205 | boi_RP:x24 | N/A |
| 22.1 | Total Tier 1 equity capital, after supervisory reconciliations and deductions/Basel III | boi_met:mi15 | xbrli:monetaryItemType | instant | boi_BC:x15 | boi_CS:x2 | N/A | boi_MC:x193 | boi_RP:x24 | N/A |
| 23.1 | Total Tier 1 capital, after supervisory reconciliations and deductions/Basel III | boi_met:mi15 | xbrli:monetaryItemType | instant | boi_BC:x15 | boi_CS:x2 | N/A | boi_MC:x596 | boi_RP:x24 | N/A |
| r31.1 | Tier 2 capital/Basel III | boi_met:mi15 | xbrli:monetaryItemType | instant | boi_BC:x15 | boi_CS:x2 | N/A | N/A | boi_RP:x24 | N/A |
| 24.1 | Tier 2 capital: instruments, before deductions/Basel III | boi_met:mi15 | xbrli:monetaryItemType | instant | boi_BC:x15 | boi_CS:x2 | N/A | boi_MC:x582 | boi_RP:x24 | N/A |
| 25.1 | Tier 2 capital: allowances, before deductions/Basel III | boi_met:mi15 | xbrli:monetaryItemType | instant | boi_BC:x15 | boi_CS:x2 | N/A | boi_MC:x235 | boi_RP:x24 | N/A |
| 26.1 | Total Tier 2 capital, before deductions/Basel III | boi_met:mi15 | xbrli:monetaryItemType | instant | boi_BC:x15 | boi_CS:x2 | N/A | boi_MC:x230 | boi_RP:x24 | N/A |
| 27.1 | Total deductions: Tier 2 capital/Basel III | boi_met:mi15 | xbrli:monetaryItemType | instant | boi_BC:x15 | boi_CS:x2 | N/A | boi_MC:x236 | boi_RP:x24 | N/A |
| 28.1 | Total Tier 2 capital/Basel III | boi_met:mi15 | xbrli:monetaryItemType | instant | boi_BC:x15 | boi_CS:x2 | N/A | boi_MC:x229 | boi_RP:x24 | N/A |