| r0.1 | label_boi_a2/Commercial | | | | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x4 | N/A | N/A | N/A |
| r0.2 | label_boi_a2/For housing | | | | boi_BC:x1 | boi_CL:x35 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | N/A | N/A | N/A |
| r0.3 | label_boi_a2/Other private | | | | boi_BC:x1 | boi_CL:x38 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | N/A | N/A | N/A |
| r0.4 | label_boi_a2/Total | | | | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x16 | N/A | N/A | N/A |
| r0.5 | label_boi_a2/Banks and governments | | | | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x77 | N/A | 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 | N/A | N/A |
| r1.1 | Recorded debit balance of debts/Commercial | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x4 | N/A | N/A | N/A |
| r1.2 | Recorded debit balance of debts/For housing | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | N/A | N/A | N/A |
| r1.3 | Recorded debit balance of debts/Other private | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x38 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | N/A | N/A | N/A |
| r1.4 | Recorded debit balance of debts/Total | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x16 | N/A | N/A | N/A |
| r1.5 | Recorded debit balance of debts/Banks and governments | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x77 | N/A | N/A | N/A |
| r1.6 | Recorded debit balance of 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 | N/A | N/A |
| 1.1 | Examined on an individual basis/Commercial | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x4 | boi_ST:x28 | N/A | N/A |
| 1.2 | Examined on an individual basis/For housing | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | boi_ST:x28 | N/A | N/A |
| 1.3 | Examined on an individual basis/Other private | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x38 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | boi_ST:x28 | N/A | N/A |
| 1.4 | 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 | boi_SE:x16 | boi_ST:x28 | N/A | N/A |
| 1.5 | Examined on an individual basis/Banks and governments | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x77 | boi_ST:x28 | N/A | N/A |
| 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 | N/A | N/A |
| 2.1 | Examined on a group bais/Commercial | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x4 | boi_ST:x29 | N/A | N/A |
| 2.2 | Examined on a group bais/For housing | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | boi_ST:x29 | N/A | N/A |
| 2.3 | Examined on a group bais/Other private | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x38 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | boi_ST:x29 | N/A | N/A |
| 2.4 | Examined on a group bais/Total | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x16 | boi_ST:x29 | N/A | N/A |
| 2.5 | Examined on a group bais/Banks and governments | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x77 | boi_ST:x29 | N/A | N/A |
| 2.6 | Examined on a group bais/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 | N/A | N/A |
| 3.1 | Of which: Allowance that was calculated by extent of arrears/Commercial | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x4 | boi_ST:x33 | N/A | N/A |
| 3.2 | Of which: Allowance that was calculated by extent of arrears/For housing | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | boi_ST:x33 | N/A | N/A |
| 3.3 | Of which: Allowance that was calculated by extent of arrears/Other private | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x38 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | boi_ST:x33 | N/A | N/A |
| 3.4 | Of which: Allowance that was calculated by extent of arrears/Total | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x16 | boi_ST:x33 | N/A | N/A |
| 3.5 | Of which: Allowance that was calculated by extent of arrears/Banks and governments | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x77 | boi_ST:x33 | N/A | N/A |
| 3.6 | Of which: Allowance that was calculated by extent of arrears/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:x33 | N/A | N/A |
| 4.1 | Total debts/Commercial | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x4 | N/A | N/A | N/A |
| 4.2 | Total debts/For housing | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | N/A | N/A | N/A |
| 4.3 | Total debts/Other private | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x38 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | N/A | N/A | N/A |
| 4.4 | Total debts/Total | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x16 | N/A | N/A | N/A |
| 4.5 | Total debts/Banks and governments | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x77 | N/A | N/A | N/A |
| 4.6 | 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 | N/A | N/A |
| 5.1 | Of which: recycled debts/Commercial | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x4 | boi_ST:x3 | boi_ST:x25 | N/A |
| 5.2 | Of which: recycled debts/For housing | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | boi_ST:x3 | boi_ST:x25 | N/A |
| 5.3 | Of which: recycled debts/Other private | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x38 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | boi_ST:x3 | boi_ST:x25 | N/A |
| 5.4 | Of which: recycled debts/Total | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x16 | boi_ST:x3 | boi_ST:x25 | N/A |
| 5.5 | Of which: recycled debts/Banks and governments | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x77 | boi_ST:x3 | boi_ST:x25 | N/A |
| 5.6 | Of which: recycled debts/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:x3 | boi_ST:x25 | N/A |
| 6.1 | Of which: other impaired debts/Commercial | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x4 | boi_ST:x3 | boi_ST:x152 | N/A |
| 6.2 | Of which: other impaired debts/For housing | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | boi_ST:x3 | boi_ST:x152 | N/A |
| 6.3 | Of which: other impaired debts/Other private | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x38 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | boi_ST:x3 | boi_ST:x152 | N/A |
| 6.4 | Of which: other impaired debts/Total | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x16 | boi_ST:x3 | boi_ST:x152 | N/A |
| 6.5 | Of which: other impaired debts/Banks and governments | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x77 | boi_ST:x3 | boi_ST:x152 | N/A |
| 6.6 | Of which: other impaired debts/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:x3 | boi_ST:x152 | N/A |
| 7.1 | Of which: total impaired debts/Commercial | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x4 | boi_ST:x3 | N/A | N/A |
| 7.2 | Of which: total impaired debts/For housing | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | boi_ST:x3 | N/A | N/A |
| 7.3 | Of which: total impaired debts/Other private | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x38 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | boi_ST:x3 | N/A | N/A |
| 7.4 | Of which: total impaired debts/Total | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x16 | boi_ST:x3 | N/A | N/A |
| 7.5 | Of which: total impaired debts/Banks and governments | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x77 | boi_ST:x3 | N/A | N/A |
| 7.6 | Of which: total impaired debts/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:x3 | N/A | N/A |
| 8.1 | Of which: Problematic debts 90 days and more/Commercial | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x4 | boi_ST:x4 | N/A | boi_TI:x2 |
| 8.2 | Of which: Problematic debts 90 days and more/For housing | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | boi_ST:x4 | N/A | boi_TI:x2 |
| 8.3 | Of which: Problematic debts 90 days and more/Other private | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x38 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | boi_ST:x4 | N/A | boi_TI:x2 |
| 8.4 | Of which: Problematic debts 90 days and more/Total | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x16 | boi_ST:x4 | N/A | boi_TI:x2 |
| 8.5 | Of which: Problematic debts 90 days and more/Banks and governments | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x77 | boi_ST:x4 | N/A | boi_TI:x2 |
| 8.6 | Of which: Problematic debts 90 days and more/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:x4 | N/A | boi_TI:x2 |
| 9.1 | Of which: Other problematic debts/Commercial | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x4 | boi_ST:x4 | N/A | boi_TI:x94 |
| 9.2 | Of which: Other problematic debts/For housing | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | boi_ST:x4 | N/A | boi_TI:x94 |
| 9.3 | Of which: Other problematic debts/Other private | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x38 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | boi_ST:x4 | N/A | boi_TI:x94 |
| 9.4 | Of which: Other problematic debts/Total | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x16 | boi_ST:x4 | N/A | boi_TI:x94 |
| 9.5 | Of which: Other problematic debts/Banks and governments | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x77 | boi_ST:x4 | N/A | boi_TI:x94 |
| 9.6 | Of which: Other problematic debts/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:x4 | N/A | boi_TI:x94 |
| 10.1 | Of which: Problem debts - not impaired/Commercial | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x4 | boi_ST:x2 | N/A | N/A |
| 10.2 | Of which: Problem debts - not impaired/For housing | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | boi_ST:x2 | N/A | N/A |
| 10.3 | Of which: Problem debts - not impaired/Other private | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x38 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | boi_ST:x2 | N/A | N/A |
| 10.4 | Of which: Problem debts - not impaired/Total | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x16 | boi_ST:x2 | N/A | N/A |
| 10.5 | Of which: Problem debts - not impaired/Banks and governments | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x77 | boi_ST:x2 | N/A | N/A |
| 10.6 | Of which: Problem debts - not impaired/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:x2 | N/A | N/A |
| r12.1 | Credit loss allowance by debts/Commercial | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x4 | N/A | N/A | N/A |
| r12.2 | Credit loss allowance by debts/For housing | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | N/A | N/A | N/A |
| r12.3 | Credit loss allowance by debts/Other private | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x38 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | N/A | N/A | N/A |
| r12.4 | Credit loss allowance by debts/Total | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x16 | N/A | N/A | N/A |
| r12.5 | Credit loss allowance by debts/Banks and governments | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x77 | N/A | N/A | N/A |
| r12.6 | Credit loss allowance by debts/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 | N/A | N/A |
| 11.1 | Examined on an individual basis/Commercial | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x4 | boi_ST:x28 | N/A | N/A |
| 11.2 | Examined on an individual basis/For housing | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | boi_ST:x28 | N/A | N/A |
| 11.3 | Examined on an individual basis/Other private | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x38 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | boi_ST:x28 | N/A | N/A |
| 11.4 | 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 | boi_SE:x16 | boi_ST:x28 | N/A | N/A |
| 11.5 | Examined on an individual basis/Banks and governments | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x77 | boi_ST:x28 | N/A | N/A |
| 11.6 | 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 | N/A | N/A |
| 12.1 | Examined on a group basis/Commercial | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x4 | boi_ST:x29 | N/A | N/A |
| 12.2 | Examined on a group basis/For housing | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | boi_ST:x29 | N/A | N/A |
| 12.3 | Examined on a group basis/Other private | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x38 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | boi_ST:x29 | N/A | N/A |
| 12.4 | 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 | boi_SE:x16 | boi_ST:x29 | N/A | N/A |
| 12.5 | Examined on a group basis/Banks and governments | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x77 | boi_ST:x29 | N/A | N/A |
| 12.6 | 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 | N/A | N/A |
| 13.1 | Of which: Allowance that was calculated by extent of arrears/Commercial | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x4 | boi_ST:x33 | N/A | N/A |
| 13.2 | Of which: Allowance that was calculated by extent of arrears/For housing | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | boi_ST:x33 | N/A | N/A |
| 13.3 | Of which: Allowance that was calculated by extent of arrears/Other private | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x38 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | boi_ST:x33 | N/A | N/A |
| 13.4 | Of which: Allowance that was calculated by extent of arrears/Total | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x16 | boi_ST:x33 | N/A | N/A |
| 13.5 | Of which: Allowance that was calculated by extent of arrears/Banks and governments | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x77 | boi_ST:x33 | N/A | N/A |
| 13.6 | Of which: Allowance that was calculated by extent of arrears/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:x33 | N/A | N/A |
| 14.1 | Including balance of allowance beyond that required, calculated on an individual basis/Commercial | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x4 | boi_ST:x34 | N/A | N/A |
| 14.2 | Including balance of allowance beyond that required, calculated on an individual basis/For housing | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | boi_ST:x34 | N/A | N/A |
| 14.3 | Including balance of allowance beyond that required, calculated on an individual basis/Other private | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x38 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | boi_ST:x34 | N/A | N/A |
| 14.4 | Including balance of allowance beyond that required, calculated 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 | boi_SE:x16 | boi_ST:x34 | N/A | N/A |
| 14.5 | Including balance of allowance beyond that required, calculated on an individual basis/Banks and governments | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x77 | boi_ST:x34 | N/A | N/A |
| 14.6 | Including balance of allowance beyond that required, calculated 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:x34 | N/A | N/A |
| 15.1 | Incuding balance of allowance beyond that required, calculated on a group basis/Commercial | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x4 | boi_ST:x35 | N/A | N/A |
| 15.2 | Incuding balance of allowance beyond that required, calculated on a group basis/For housing | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | boi_ST:x35 | N/A | N/A |
| 15.3 | Incuding balance of allowance beyond that required, calculated on a group basis/Other private | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x38 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | boi_ST:x35 | N/A | N/A |
| 15.4 | Incuding balance of allowance beyond that required, calculated 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 | boi_SE:x16 | boi_ST:x35 | N/A | N/A |
| 15.5 | Incuding balance of allowance beyond that required, calculated on a group basis/Banks and governments | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x77 | boi_ST:x35 | N/A | N/A |
| 15.6 | Incuding balance of allowance beyond that required, calculated 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:x35 | N/A | N/A |
| 16.1 | Calculated on a group basis/Commercial | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x4 | N/A | N/A | N/A |
| 16.2 | Calculated on a group basis/For housing | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | N/A | N/A | N/A |
| 16.3 | Calculated on a group basis/Other private | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x38 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | N/A | N/A | N/A |
| 16.4 | Calculated 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 | boi_SE:x16 | N/A | N/A | N/A |
| 16.5 | Calculated on a group basis/Banks and governments | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x77 | N/A | N/A | N/A |
| 16.6 | Calculated 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 | N/A | N/A | N/A |
| 17.1 | of which: for impaired debts/Commercial | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x4 | boi_ST:x3 | N/A | N/A |
| 17.2 | of which: for impaired debts/For housing | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | boi_ST:x3 | N/A | N/A |
| 17.3 | of which: for impaired debts/Other private | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x38 | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x15 | boi_ST:x3 | N/A | N/A |
| 17.4 | of which: for impaired debts/Total | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x16 | boi_ST:x3 | N/A | N/A |
| 17.5 | of which: for impaired debts/Banks and governments | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x2 | boi_MC:x640 | boi_RP:x24 | boi_SE:x77 | boi_ST:x3 | N/A | N/A |
| 17.6 | of which: for impaired debts/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:x3 | N/A | N/A |