| r0.1 | label_boi_a2/Receivables in respect of credit cards | | | | boi_BC:x1 | boi_CL:x2 | boi_CS:x2 | boi_MC:x143 | boi_RP:x24 | boi_SE:x15 | N/A |
| r0.2 | label_boi_a2/Credit2 | | | | boi_BC:x1 | boi_CL:x2 | boi_CS:x2 | boi_MC:x880 | boi_RP:x24 | boi_SE:x15 | N/A |
| r0.3 | label_boi_a2/Receivables in respect of credit cards | | | | boi_BC:x1 | boi_CL:x2 | boi_CS:x2 | boi_MC:x143 | boi_RP:x24 | boi_SE:x4 | N/A |
| r0.4 | label_boi_a2/Credit2,3 | | | | boi_BC:x1 | boi_CL:x2 | boi_CS:x2 | boi_MC:x880 | boi_RP:x24 | boi_SE:x4 | N/A |
| r0.5 | label_boi_a2/Credit risk guaranteed by banks and other | | | | boi_BC:x1 | boi_CL:x40 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | N/A | N/A |
| r0.6 | label_boi_a2/Total | | | | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | N/A | N/A |
| r1.1 | Recorded debt balance of debts1/Receivables in respect of credit cards | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x2 | boi_CS:x2 | boi_MC:x143 | boi_RP:x24 | boi_SE:x15 | N/A |
| r1.2 | Recorded debt balance of debts1/Credit2 | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x2 | boi_CS:x2 | boi_MC:x880 | boi_RP:x24 | boi_SE:x15 | N/A |
| r1.3 | Recorded debt balance of debts1/Receivables in respect of credit cards | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x2 | boi_CS:x2 | boi_MC:x143 | boi_RP:x24 | boi_SE:x4 | N/A |
| r1.4 | Recorded debt balance of debts1/Credit2,3 | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x2 | boi_CS:x2 | boi_MC:x880 | boi_RP:x24 | boi_SE:x4 | N/A |
| r1.5 | Recorded debt balance of debts1/Credit risk guaranteed by banks and other | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x40 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | N/A | N/A |
| r1.6 | Recorded debt balance of debts1/Total | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | N/A | N/A |
| 1.1 | Examined on an individual basis/Receivables in respect of credit cards | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x2 | boi_CS:x2 | boi_MC:x143 | boi_RP:x24 | boi_SE:x15 | boi_ST:x28 |
| 1.2 | Examined on an individual basis/Credit2 | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x2 | boi_CS:x2 | boi_MC:x880 | boi_RP:x24 | boi_SE:x15 | boi_ST:x28 |
| 1.3 | Examined on an individual basis/Receivables in respect of credit cards | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x2 | boi_CS:x2 | boi_MC:x143 | boi_RP:x24 | boi_SE:x4 | boi_ST:x28 |
| 1.4 | Examined on an individual basis/Credit2,3 | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x2 | boi_CS:x2 | boi_MC:x880 | boi_RP:x24 | boi_SE:x4 | boi_ST:x28 |
| 1.5 | Examined on an individual basis/Credit risk guaranteed by banks and other | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x40 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | N/A | boi_ST:x28 |
| 1.6 | Examined on an individual basis/Total | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | N/A | boi_ST:x28 |
| 2.1 | Examined on a group basis/Receivables in respect of credit cards | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x2 | boi_CS:x2 | boi_MC:x143 | boi_RP:x24 | boi_SE:x15 | boi_ST:x29 |
| 2.2 | Examined on a group basis/Credit2 | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x2 | boi_CS:x2 | boi_MC:x880 | boi_RP:x24 | boi_SE:x15 | boi_ST:x29 |
| 2.3 | Examined on a group basis/Receivables in respect of credit cards | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x2 | boi_CS:x2 | boi_MC:x143 | boi_RP:x24 | boi_SE:x4 | boi_ST:x29 |
| 2.4 | Examined on a group basis/Credit2,3 | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x2 | boi_CS:x2 | boi_MC:x880 | boi_RP:x24 | boi_SE:x4 | boi_ST:x29 |
| 2.5 | Examined on a group basis/Credit risk guaranteed by banks and other | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x40 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | N/A | boi_ST:x29 |
| 2.6 | Examined on a group basis/Total | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | N/A | boi_ST:x29 |
| 3.1 | Total debts/Receivables in respect of credit cards | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x2 | boi_CS:x2 | boi_MC:x143 | boi_RP:x24 | boi_SE:x15 | N/A |
| 3.2 | Total debts/Credit2 | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x2 | boi_CS:x2 | boi_MC:x880 | boi_RP:x24 | boi_SE:x15 | N/A |
| 3.3 | Total debts/Receivables in respect of credit cards | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x2 | boi_CS:x2 | boi_MC:x143 | boi_RP:x24 | boi_SE:x4 | N/A |
| 3.4 | Total debts/Credit2,3 | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x2 | boi_CS:x2 | boi_MC:x880 | boi_RP:x24 | boi_SE:x4 | N/A |
| 3.5 | Total debts/Credit risk guaranteed by banks and other | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x40 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | N/A | N/A |
| 3.6 | Total debts/Total | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | N/A | N/A |
| r5.1 | Allowance for credit losses in respect of debts1/Receivables in respect of credit cards | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x2 | boi_CS:x2 | boi_MC:x143 | boi_RP:x24 | boi_SE:x15 | N/A |
| r5.2 | Allowance for credit losses in respect of debts1/Credit2 | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x2 | boi_CS:x2 | boi_MC:x880 | boi_RP:x24 | boi_SE:x15 | N/A |
| r5.3 | Allowance for credit losses in respect of debts1/Receivables in respect of credit cards | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x2 | boi_CS:x2 | boi_MC:x143 | boi_RP:x24 | boi_SE:x4 | N/A |
| r5.4 | Allowance for credit losses in respect of debts1/Credit2,3 | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x2 | boi_CS:x2 | boi_MC:x880 | boi_RP:x24 | boi_SE:x4 | N/A |
| r5.5 | Allowance for credit losses in respect of debts1/Credit risk guaranteed by banks and other | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x40 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | N/A | N/A |
| r5.6 | Allowance for credit losses in respect of debts1/Total | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | N/A | N/A |
| 4.1 | Examined on an individual basis/Receivables in respect of credit cards | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x2 | boi_CS:x2 | boi_MC:x143 | boi_RP:x24 | boi_SE:x15 | boi_ST:x28 |
| 4.2 | Examined on an individual basis/Credit2 | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x2 | boi_CS:x2 | boi_MC:x880 | boi_RP:x24 | boi_SE:x15 | boi_ST:x28 |
| 4.3 | Examined on an individual basis/Receivables in respect of credit cards | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x2 | boi_CS:x2 | boi_MC:x143 | boi_RP:x24 | boi_SE:x4 | boi_ST:x28 |
| 4.4 | Examined on an individual basis/Credit2,3 | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x2 | boi_CS:x2 | boi_MC:x880 | boi_RP:x24 | boi_SE:x4 | boi_ST:x28 |
| 4.5 | Examined on an individual basis/Credit risk guaranteed by banks and other | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x40 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | N/A | boi_ST:x28 |
| 4.6 | Examined on an individual basis/Total | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | N/A | boi_ST:x28 |
| 5.1 | Examined on a group basis/Receivables in respect of credit cards | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x2 | boi_CS:x2 | boi_MC:x143 | boi_RP:x24 | boi_SE:x15 | boi_ST:x29 |
| 5.2 | Examined on a group basis/Credit2 | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x2 | boi_CS:x2 | boi_MC:x880 | boi_RP:x24 | boi_SE:x15 | boi_ST:x29 |
| 5.3 | Examined on a group basis/Receivables in respect of credit cards | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x2 | boi_CS:x2 | boi_MC:x143 | boi_RP:x24 | boi_SE:x4 | boi_ST:x29 |
| 5.4 | Examined on a group basis/Credit2,3 | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x2 | boi_CS:x2 | boi_MC:x880 | boi_RP:x24 | boi_SE:x4 | boi_ST:x29 |
| 5.5 | Examined on a group basis/Credit risk guaranteed by banks and other | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x40 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | N/A | boi_ST:x29 |
| 5.6 | Examined on a group basis/Total | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | N/A | boi_ST:x29 |
| 6.1 | Total allowance for credit losses/Receivables in respect of credit cards | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x2 | boi_CS:x2 | boi_MC:x143 | boi_RP:x24 | boi_SE:x15 | N/A |
| 6.2 | Total allowance for credit losses/Credit2 | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x2 | boi_CS:x2 | boi_MC:x880 | boi_RP:x24 | boi_SE:x15 | N/A |
| 6.3 | Total allowance for credit losses/Receivables in respect of credit cards | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x2 | boi_CS:x2 | boi_MC:x143 | boi_RP:x24 | boi_SE:x4 | N/A |
| 6.4 | Total allowance for credit losses/Credit2,3 | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x2 | boi_CS:x2 | boi_MC:x880 | boi_RP:x24 | boi_SE:x4 | N/A |
| 6.5 | Total allowance for credit losses/Credit risk guaranteed by banks and other | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x40 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | N/A | N/A |
| 6.6 | Total allowance for credit losses/Total | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | N/A | N/A |