| r0.2 | label_boi_a2/Recorded interest income | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | N/A | boi_CS:x2 | boi_MC:x125 | N/A | boi_RP:x19 | N/A | boi_ST:x3 |
| r0.3 | label_boi_a2/Of which: recorded on cash basis | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | N/A | boi_CS:x2 | boi_MC:x125 | N/A | boi_RP:x19 | N/A | boi_ST:x30 |
| r1.2 | Debts not guaranteed by banks/Recorded interest income | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | boi_CL:x2 | boi_CS:x2 | boi_MC:x125 | N/A | boi_RP:x19 | N/A | boi_ST:x3 |
| r1.3 | Debts not guaranteed by banks/Of which: recorded on cash basis | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | boi_CL:x2 | boi_CS:x2 | boi_MC:x125 | N/A | boi_RP:x19 | N/A | boi_ST:x30 |
| r2.2 | Private individuals/Recorded interest income | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | boi_CL:x2 | boi_CS:x2 | boi_MC:x125 | N/A | boi_RP:x19 | boi_SE:x15 | boi_ST:x3 |
| r2.3 | Private individuals/Of which: recorded on cash basis | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | boi_CL:x2 | boi_CS:x2 | boi_MC:x125 | N/A | boi_RP:x19 | boi_SE:x15 | boi_ST:x30 |
| 1.2 | Receivables in respect of credit cards/Recorded interest income | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | boi_CL:x2 | boi_CS:x2 | boi_MC:x125 | boi_MC:x143 | boi_RP:x19 | boi_SE:x15 | boi_ST:x3 |
| 1.3 | Receivables in respect of credit cards/Of which: recorded on cash basis | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | boi_CL:x2 | boi_CS:x2 | boi_MC:x125 | boi_MC:x143 | boi_RP:x19 | boi_SE:x15 | boi_ST:x30 |
| 2.2 | Credit 4/Recorded interest income | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | boi_CL:x2 | boi_CS:x2 | boi_MC:x125 | boi_MC:x880 | boi_RP:x19 | boi_SE:x15 | boi_ST:x3 |
| 2.3 | Credit 4/Of which: recorded on cash basis | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | boi_CL:x2 | boi_CS:x2 | boi_MC:x125 | boi_MC:x880 | boi_RP:x19 | boi_SE:x15 | boi_ST:x30 |
| r5.2 | Commercial/Recorded interest income | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | boi_CL:x2 | boi_CS:x2 | boi_MC:x125 | N/A | boi_RP:x19 | boi_SE:x4 | boi_ST:x3 |
| r5.3 | Commercial/Of which: recorded on cash basis | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | boi_CL:x2 | boi_CS:x2 | boi_MC:x125 | N/A | boi_RP:x19 | boi_SE:x4 | boi_ST:x30 |
| 3.2 | Receivables in respect of credit cards/Recorded interest income | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | boi_CL:x2 | boi_CS:x2 | boi_MC:x125 | boi_MC:x143 | boi_RP:x19 | boi_SE:x4 | boi_ST:x3 |
| 3.3 | Receivables in respect of credit cards/Of which: recorded on cash basis | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | boi_CL:x2 | boi_CS:x2 | boi_MC:x125 | boi_MC:x143 | boi_RP:x19 | boi_SE:x4 | boi_ST:x30 |
| 4.2 | Credit 5/Recorded interest income | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | boi_CL:x2 | boi_CS:x2 | boi_MC:x125 | boi_MC:x880 | boi_RP:x19 | boi_SE:x4 | boi_ST:x3 |
| 4.3 | Credit 5/Of which: recorded on cash basis | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | boi_CL:x2 | boi_CS:x2 | boi_MC:x125 | boi_MC:x880 | boi_RP:x19 | boi_SE:x4 | boi_ST:x30 |
| 5.2 | Total debts not guaranteed by banks/Recorded interest income | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | boi_CL:x2 | boi_CS:x2 | boi_MC:x125 | boi_MC:x8 | boi_RP:x19 | N/A | boi_ST:x3 |
| 5.3 | Total debts not guaranteed by banks/Of which: recorded on cash basis | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | boi_CL:x2 | boi_CS:x2 | boi_MC:x125 | boi_MC:x8 | boi_RP:x19 | N/A | boi_ST:x30 |
| 6.2 | Debts guaranteed by banks and others/Recorded interest income | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | boi_CL:x40 | boi_CS:x2 | boi_MC:x125 | boi_MC:x8 | boi_RP:x19 | N/A | boi_ST:x3 |
| 6.3 | Debts guaranteed by banks and others/Of which: recorded on cash basis | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | boi_CL:x40 | boi_CS:x2 | boi_MC:x125 | boi_MC:x8 | boi_RP:x19 | N/A | boi_ST:x30 |
| 7.2 | Total/Recorded interest income | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | N/A | boi_CS:x2 | boi_MC:x125 | boi_MC:x8 | boi_RP:x19 | N/A | boi_ST:x3 |
| 7.3 | Total/Of which: recorded on cash basis | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | N/A | boi_CS:x2 | boi_MC:x125 | boi_MC:x8 | boi_RP:x19 | N/A | boi_ST:x30 |