| r0.1 | label_boi_a2/Impaired or in arrears of 90 days or more | boi_met:mi1305 | xbrli:monetaryItemType | instant | boi_BC:x16 | boi_CS:x2 | N/A | boi_RP:x24 | boi_RT:x21 | boi_ST:x2 |
| r0.2 | label_boi_a2/Others | boi_met:mi1306 | xbrli:monetaryItemType | instant | boi_BC:x16 | boi_CS:x2 | N/A | boi_RP:x24 | boi_RT:x21 | boi_ST:x1 |
| r0.3 | label_boi_a2/Allowances for credit losses or impairment | boi_met:mi1303 | xbrli:monetaryItemType | instant | boi_BC:x16 | boi_CS:x2 | N/A | boi_RP:x24 | boi_RT:x21 | N/A |
| r0.4 | label_boi_a2/Net balances | boi_met:mi18 | xbrli:monetaryItemType | instant | boi_BC:x16 | boi_CS:x2 | N/A | boi_RP:x24 | boi_RT:x21 | N/A |
| 1.1 | Debts, excluding bonds/Impaired or in arrears of 90 days or more | boi_met:mi1305 | xbrli:monetaryItemType | instant | boi_BC:x16 | boi_CS:x2 | boi_MC:x8 | boi_RP:x24 | boi_RT:x21 | boi_ST:x2 |
| 1.2 | Debts, excluding bonds/Others | boi_met:mi1306 | xbrli:monetaryItemType | instant | boi_BC:x16 | boi_CS:x2 | boi_MC:x8 | boi_RP:x24 | boi_RT:x21 | boi_ST:x1 |
| 1.3 | Debts, excluding bonds/Allowances for credit losses or impairment | boi_met:mi1303 | xbrli:monetaryItemType | instant | boi_BC:x16 | boi_CS:x2 | boi_MC:x8 | boi_RP:x24 | boi_RT:x21 | N/A |
| 1.4 | Debts, excluding bonds/Net balances | boi_met:mi18 | xbrli:monetaryItemType | instant | boi_BC:x16 | boi_CS:x2 | boi_MC:x8 | boi_RP:x24 | boi_RT:x21 | N/A |
| 2.1 | Bonds/Impaired or in arrears of 90 days or more | boi_met:mi1305 | xbrli:monetaryItemType | instant | boi_BC:x16 | boi_CS:x2 | boi_MC:x15 | boi_RP:x24 | boi_RT:x21 | boi_ST:x2 |
| 2.2 | Bonds/Others | boi_met:mi1306 | xbrli:monetaryItemType | instant | boi_BC:x16 | boi_CS:x2 | boi_MC:x15 | boi_RP:x24 | boi_RT:x21 | boi_ST:x1 |
| 2.3 | Bonds/Allowances for credit losses or impairment | boi_met:mi1303 | xbrli:monetaryItemType | instant | boi_BC:x16 | boi_CS:x2 | boi_MC:x15 | boi_RP:x24 | boi_RT:x21 | N/A |
| 2.4 | Bonds/Net balances | boi_met:mi18 | xbrli:monetaryItemType | instant | boi_BC:x16 | boi_CS:x2 | boi_MC:x15 | boi_RP:x24 | boi_RT:x21 | N/A |
| 3.1 | Off-balance sheet exposures/Impaired or in arrears of 90 days or more | boi_met:mi1305 | xbrli:monetaryItemType | instant | boi_BC:x16 | boi_CS:x2 | boi_MC:x243 | boi_RP:x24 | boi_RT:x21 | boi_ST:x2 |
| 3.2 | Off-balance sheet exposures/Others | boi_met:mi1306 | xbrli:monetaryItemType | instant | boi_BC:x16 | boi_CS:x2 | boi_MC:x243 | boi_RP:x24 | boi_RT:x21 | boi_ST:x1 |
| 3.3 | Off-balance sheet exposures/Allowances for credit losses or impairment | boi_met:mi1303 | xbrli:monetaryItemType | instant | boi_BC:x16 | boi_CS:x2 | boi_MC:x243 | boi_RP:x24 | boi_RT:x21 | N/A |
| 3.4 | Off-balance sheet exposures/Net balances | boi_met:mi18 | xbrli:monetaryItemType | instant | boi_BC:x16 | boi_CS:x2 | boi_MC:x243 | boi_RP:x24 | boi_RT:x21 | N/A |
| 4.1 | Total/Impaired or in arrears of 90 days or more | boi_met:mi1305 | xbrli:monetaryItemType | instant | boi_BC:x16 | boi_CS:x2 | boi_MC:x1139 | boi_RP:x24 | boi_RT:x21 | boi_ST:x2 |
| 4.2 | Total/Others | boi_met:mi1306 | xbrli:monetaryItemType | instant | boi_BC:x16 | boi_CS:x2 | boi_MC:x1139 | boi_RP:x24 | boi_RT:x21 | boi_ST:x1 |
| 4.3 | Total/Allowances for credit losses or impairment | boi_met:mi1303 | xbrli:monetaryItemType | instant | boi_BC:x16 | boi_CS:x2 | boi_MC:x1139 | boi_RP:x24 | boi_RT:x21 | N/A |
| 4.4 | Total/Net balances | boi_met:mi18 | xbrli:monetaryItemType | instant | boi_BC:x16 | boi_CS:x2 | boi_MC:x1139 | boi_RP:x24 | boi_RT:x21 | N/A |