| r0.1 | label_boi_a2/Consolidated | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | N/A | N/A | boi_MU:x1 | boi_RP:x25 |
| r0.2 | label_boi_a2/Company | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x1 | N/A | N/A | boi_MU:x1 | boi_RP:x25 |
| 1.1 | Non-interest financing income/Consolidated | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | boi_MC:x128 | N/A | boi_MU:x1 | boi_RP:x25 |
| 1.2 | Non-interest financing income/Company | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x1 | boi_MC:x128 | N/A | boi_MU:x1 | boi_RP:x25 |
| 2.1 | From leasing of assets/Consolidated | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | boi_MC:x473 | N/A | boi_MU:x1 | boi_RP:x25 |
| 2.2 | From leasing of assets/Company | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x1 | boi_MC:x473 | N/A | boi_MU:x1 | boi_RP:x25 |
| 3.1 | Capital gain from sale of buildings and equipment/Consolidated | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | boi_MC:x156 | N/A | boi_MU:x1 | boi_RP:x25 |
| 3.2 | Capital gain from sale of buildings and equipment/Company | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x1 | boi_MC:x156 | N/A | boi_MU:x1 | boi_RP:x25 |
| 4.1 | Capital loss from sale of buildings and equipment/Consolidated | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | boi_MC:x157 | N/A | boi_MU:x1 | boi_RP:x25 |
| 4.2 | Capital loss from sale of buildings and equipment/Company | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x1 | boi_MC:x157 | N/A | boi_MU:x1 | boi_RP:x25 |
| 5.1 | Other (provide breakdown if material)/Consolidated | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | boi_MC:x474 | N/A | boi_MU:x1 | boi_RP:x25 |
| 5.2 | Other (provide breakdown if material)/Company | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x1 | boi_MC:x474 | N/A | boi_MU:x1 | boi_RP:x25 |
| 6.1 | Total other income/Consolidated | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | boi_MC:x456 | N/A | boi_MU:x1 | boi_RP:x25 |
| 6.2 | Total other income/Company | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x1 | boi_MC:x456 | N/A | boi_MU:x1 | boi_RP:x25 |
| 7.1 | Of which: In respect of sale and leaseback transactions of buildings and equipment/Consolidated | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | boi_MC:x1153 | boi_MC:x929 | boi_MU:x1 | boi_RP:x25 |
| 7.2 | Of which: In respect of sale and leaseback transactions of buildings and equipment/Company | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x1 | boi_MC:x1153 | boi_MC:x929 | boi_MU:x1 | boi_RP:x25 |