| r0.1 | label_boi_a2/Consolidated | | | | boi_BC:x8 | N/A | boi_CS:x2 | N/A | boi_RP:x24 |
| r0.2 | label_boi_a2/Company | | | | boi_BC:x8 | N/A | boi_CS:x1 | N/A | boi_RP:x24 |
| r1.1 | Unutilized credit card facilities:/Consolidated | | | | boi_BC:x8 | N/A | boi_CS:x2 | boi_MC:x74 | boi_RP:x24 |
| r1.2 | Unutilized credit card facilities:/Company | | | | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x74 | boi_RP:x24 |
| 1.1 | Credit risk to company/Consolidated | boi_met:mi204 | xbrli:monetaryItemType | instant | boi_BC:x8 | boi_CL:x2 | boi_CS:x2 | boi_MC:x74 | boi_RP:x24 |
| 1.2 | Credit risk to company/Company | boi_met:mi204 | xbrli:monetaryItemType | instant | boi_BC:x8 | boi_CL:x2 | boi_CS:x1 | boi_MC:x74 | boi_RP:x24 |
| 2.1 | Credit risk to bank/Consolidated | boi_met:mi204 | xbrli:monetaryItemType | instant | boi_BC:x8 | boi_CL:x1 | boi_CS:x2 | boi_MC:x74 | boi_RP:x24 |
| 2.2 | Credit risk to bank/Company | boi_met:mi204 | xbrli:monetaryItemType | instant | boi_BC:x8 | boi_CL:x1 | boi_CS:x1 | boi_MC:x74 | boi_RP:x24 |
| 3.1 | Credit risk to others/Consolidated | boi_met:mi204 | xbrli:monetaryItemType | instant | boi_BC:x8 | boi_CL:x4 | boi_CS:x2 | boi_MC:x74 | boi_RP:x24 |
| 3.2 | Credit risk to others/Company | boi_met:mi204 | xbrli:monetaryItemType | instant | boi_BC:x8 | boi_CL:x4 | boi_CS:x1 | boi_MC:x74 | boi_RP:x24 |
| 4.1 | Provision for credit losses/Consolidated | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x8 | N/A | boi_CS:x2 | boi_MC:x74 | boi_RP:x24 |
| 4.2 | Provision for credit losses/Company | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x74 | boi_RP:x24 |
| 5.1 | Unutilized credit card facilities, net/Consolidated | boi_met:mi283 | xbrli:monetaryItemType | instant | boi_BC:x8 | N/A | boi_CS:x2 | boi_MC:x74 | boi_RP:x24 |
| 5.2 | Unutilized credit card facilities, net/Company | boi_met:mi283 | xbrli:monetaryItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x74 | boi_RP:x24 |
| 6.1 | Guarantees and other obligations/Consolidated | boi_met:mi204 | xbrli:monetaryItemType | instant | boi_BC:x8 | N/A | boi_CS:x2 | boi_MC:x535 | boi_RP:x24 |
| 6.2 | Guarantees and other obligations/Company | boi_met:mi204 | xbrli:monetaryItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x535 | boi_RP:x24 |
| 7.1 | Provision for credit losses/Consolidated | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x8 | N/A | boi_CS:x2 | boi_MC:x535 | boi_RP:x24 |
| 7.2 | Provision for credit losses/Company | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x535 | boi_RP:x24 |
| 8.1 | Guarantees and other obligations, net/Consolidated | boi_met:mi283 | xbrli:monetaryItemType | instant | boi_BC:x8 | N/A | boi_CS:x2 | boi_MC:x65 | boi_RP:x24 |
| 8.2 | Guarantees and other obligations, net/Company | boi_met:mi283 | xbrli:monetaryItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | boi_RP:x24 |