| r0.1 | label_boi_a2/Before tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x406 | N/A | boi_RP:x19 |
| r0.2 | label_boi_a2/Tax effect | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x408 | N/A | boi_RP:x19 |
| r0.3 | label_boi_a2/After tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x399 | N/A | boi_RP:x19 |
| r1.1 | Changes in other profit (loss) components before attribution to minority interest/Before tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x406 | N/A | boi_RP:x19 |
| r1.2 | Changes in other profit (loss) components before attribution to minority interest/Tax effect | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x408 | N/A | boi_RP:x19 |
| r1.3 | Changes in other profit (loss) components before attribution to minority interest/After tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x399 | N/A | boi_RP:x19 |
| r2.1 | Reconciliations for presentation of bonds available for sale at fair value/Before tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x406 | N/A | boi_RP:x19 |
| r2.2 | Reconciliations for presentation of bonds available for sale at fair value/Tax effect | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x408 | N/A | boi_RP:x19 |
| r2.3 | Reconciliations for presentation of bonds available for sale at fair value/After tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x399 | N/A | boi_RP:x19 |
| 1.1 | Net unutilized profits (losses) from reconciliations to fair value/Before tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x406 | boi_PL:x28 | boi_RP:x19 |
| 1.2 | Net unutilized profits (losses) from reconciliations to fair value/Tax effect | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x408 | boi_PL:x28 | boi_RP:x19 |
| 1.3 | Net unutilized profits (losses) from reconciliations to fair value/After tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x399 | boi_PL:x28 | boi_RP:x19 |
| 2.1 | Net profits (losses) reclassified to profit and loss statement/Before tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x406 | boi_PL:x29 | boi_RP:x19 |
| 2.2 | Net profits (losses) reclassified to profit and loss statement/Tax effect | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x408 | boi_PL:x29 | boi_RP:x19 |
| 2.3 | Net profits (losses) reclassified to profit and loss statement/After tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x399 | boi_PL:x29 | boi_RP:x19 |
| 3.1 | Net change during the year/Before tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x406 | boi_PL:x1 | boi_RP:x19 |
| 3.2 | Net change during the year/Tax effect | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x408 | boi_PL:x1 | boi_RP:x19 |
| 3.3 | Net change during the year/After tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x399 | boi_PL:x1 | boi_RP:x19 |
| r6.1 | Translation adjustments/Before tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x406 | N/A | boi_RP:x19 |
| r6.2 | Translation adjustments/Tax effect | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x408 | N/A | boi_RP:x19 |
| r6.3 | Translation adjustments/After tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x399 | N/A | boi_RP:x19 |
| 4.1 | Adjustments from translation of financial statements/Before tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x406 | boi_PL:x31 | boi_RP:x19 |
| 4.2 | Adjustments from translation of financial statements/Tax effect | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x408 | boi_PL:x31 | boi_RP:x19 |
| 4.3 | Adjustments from translation of financial statements/After tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x399 | boi_PL:x31 | boi_RP:x19 |
| 5.1 | Hedges/Before tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x406 | boi_PL:x32 | boi_RP:x19 |
| 5.2 | Hedges/Tax effect | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x408 | boi_PL:x32 | boi_RP:x19 |
| 5.3 | Hedges/After tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x399 | boi_PL:x32 | boi_RP:x19 |
| 6.1 | Net profits (losses) reclassified to profit and loss statement, including from realization of activity/Before tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x406 | boi_PL:x33 | boi_RP:x19 |
| 6.2 | Net profits (losses) reclassified to profit and loss statement, including from realization of activity/Tax effect | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x408 | boi_PL:x33 | boi_RP:x19 |
| 6.3 | Net profits (losses) reclassified to profit and loss statement, including from realization of activity/After tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x399 | boi_PL:x33 | boi_RP:x19 |
| 7.1 | Net change during period/Before tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x406 | boi_PL:x30 | boi_RP:x19 |
| 7.2 | Net change during period/Tax effect | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x408 | boi_PL:x30 | boi_RP:x19 |
| 7.3 | Net change during period/After tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x399 | boi_PL:x30 | boi_RP:x19 |
| r11.1 | Cash flow hedging/Before tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x406 | N/A | boi_RP:x19 |
| r11.2 | Cash flow hedging/Tax effect | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x408 | N/A | boi_RP:x19 |
| r11.3 | Cash flow hedging/After tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x399 | N/A | boi_RP:x19 |
| 8.1 | Net profits (losses) from cash flow hedges/Before tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x406 | boi_PL:x34 | boi_RP:x19 |
| 8.2 | Net profits (losses) from cash flow hedges/Tax effect | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x408 | boi_PL:x34 | boi_RP:x19 |
| 8.3 | Net profits (losses) from cash flow hedges/After tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x399 | boi_PL:x34 | boi_RP:x19 |
| 9.1 | Net losses (profits) reclassified to profit and loss statement/Before tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x406 | boi_PL:x35 | boi_RP:x19 |
| 9.2 | Net losses (profits) reclassified to profit and loss statement/Tax effect | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x408 | boi_PL:x35 | boi_RP:x19 |
| 9.3 | Net losses (profits) reclassified to profit and loss statement/After tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x399 | boi_PL:x35 | boi_RP:x19 |
| 10.1 | Net change during period/Before tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x406 | boi_PL:x27 | boi_RP:x19 |
| 10.2 | Net change during period/Tax effect | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x408 | boi_PL:x27 | boi_RP:x19 |
| 10.3 | Net change during period/After tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x399 | boi_PL:x27 | boi_RP:x19 |
| r15.1 | Employee rights/Before tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x406 | N/A | boi_RP:x19 |
| r15.2 | Employee rights/Tax effect | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x408 | N/A | boi_RP:x19 |
| r15.3 | Employee rights/After tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x399 | N/A | boi_RP:x19 |
| 11.1 | Actuarial loss (gain), net/Before tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x406 | boi_PL:x54 | boi_RP:x19 |
| 11.2 | Actuarial loss (gain), net/Tax effect | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x408 | boi_PL:x54 | boi_RP:x19 |
| 11.3 | Actuarial loss (gain), net/After tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x399 | boi_PL:x54 | boi_RP:x19 |
| 12.1 | Cost of previous service/Before tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x406 | boi_PL:x55 | boi_RP:x19 |
| 12.2 | Cost of previous service/Tax effect | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x408 | boi_PL:x55 | boi_RP:x19 |
| 12.3 | Cost of previous service/After tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x399 | boi_PL:x55 | boi_RP:x19 |
| 13.1 | Net profits (losses) reclassified to profit and loss statemen/Before tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x406 | boi_PL:x56 | boi_RP:x19 |
| 13.2 | Net profits (losses) reclassified to profit and loss statemen/Tax effect | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x408 | boi_PL:x56 | boi_RP:x19 |
| 13.3 | Net profits (losses) reclassified to profit and loss statemen/After tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x399 | boi_PL:x56 | boi_RP:x19 |
| 14.1 | Other/Before tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x406 | boi_PL:x57 | boi_RP:x19 |
| 14.2 | Other/Tax effect | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x408 | boi_PL:x57 | boi_RP:x19 |
| 14.3 | Other/After tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x399 | boi_PL:x57 | boi_RP:x19 |
| 15.1 | Net change during period/Before tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x406 | boi_PL:x53 | boi_RP:x19 |
| 15.2 | Net change during period/Tax effect | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x408 | boi_PL:x53 | boi_RP:x19 |
| 15.3 | Net change during period/After tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x399 | boi_PL:x53 | boi_RP:x19 |
| 16.1 | Total net change during period before attribution to non-controlling interests/Before tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x406 | boi_PL:x36 | boi_RP:x19 |
| 16.2 | Total net change during period before attribution to non-controlling interests/Tax effect | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x408 | boi_PL:x36 | boi_RP:x19 |
| 16.3 | Total net change during period before attribution to non-controlling interests/After tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x399 | boi_PL:x36 | boi_RP:x19 |
| 17.1 | Changes in other profit (loss) components attributed to minority interest/Before tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CN:x2 | boi_CS:x2 | boi_MC:x406 | boi_PL:x36 | boi_RP:x19 |
| 17.2 | Changes in other profit (loss) components attributed to minority interest/Tax effect | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CN:x2 | boi_CS:x2 | boi_MC:x408 | boi_PL:x36 | boi_RP:x19 |
| 17.3 | Changes in other profit (loss) components attributed to minority interest/After tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CN:x2 | boi_CS:x2 | boi_MC:x399 | boi_PL:x36 | boi_RP:x19 |
| 18.1 | Changes in profit (loss) components attributed to banking corporation's shareholders/Before tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CN:x1 | boi_CS:x2 | boi_MC:x406 | boi_PL:x36 | boi_RP:x19 |
| 18.2 | Changes in profit (loss) components attributed to banking corporation's shareholders/Tax effect | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CN:x1 | boi_CS:x2 | boi_MC:x408 | boi_PL:x36 | boi_RP:x19 |
| 18.3 | Changes in profit (loss) components attributed to banking corporation's shareholders/After tax | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CN:x1 | boi_CS:x2 | boi_MC:x399 | boi_PL:x36 | boi_RP:x19 |