| r0.1 | label_boi_a2/Past year2 | boi_met:pd511 | num:percentItemType | instant | N/A | N/A | boi_CS:x1 | N/A | boi_MU:x1 | boi_RP:x28 | N/A | N/A | N/A |
| r0.2 | label_boi_a2/Minimum | boi_met:pd512 | num:percentItemType | instant | N/A | N/A | boi_CS:x1 | N/A | boi_MU:x1 | boi_RP:x29 | N/A | N/A | N/A |
| r0.3 | label_boi_a2/Maximum | boi_met:pd513 | num:percentItemType | instant | N/A | N/A | boi_CS:x1 | N/A | boi_MU:x1 | boi_RP:x29 | N/A | N/A | N/A |
| r0.4 | label_boi_a2/Average | boi_met:pd511 | num:percentItemType | instant | N/A | N/A | boi_CS:x1 | N/A | boi_MU:x1 | boi_RP:x29 | N/A | N/A | N/A |
| r0.5 | label_boi_a2/Decision6 | boi_met:pd514 | num:percentItemType | instant | N/A | N/A | boi_CS:x1 | N/A | boi_MU:x1 | N/A | N/A | N/A | N/A |
| r0.6 | label_boi_a2/Adjustments7 | boi_met:pd515 | num:percentItemType | instant | N/A | N/A | boi_CS:x1 | N/A | boi_MU:x1 | N/A | N/A | N/A | N/A |
| r0.7 | label_boi_a2/Allowance coefficient1 | boi_met:pd510 | num:percentItemType | instant | N/A | N/A | boi_CS:x1 | N/A | boi_MU:x1 | N/A | N/A | N/A | N/A |
| r0.8 | label_boi_a2/Recorded debt balance2 | boi_met:mi468 | xbrli:monetaryItemType | instant | N/A | N/A | boi_CS:x1 | N/A | N/A | N/A | N/A | N/A | N/A |
| r0.9 | label_boi_a2/Balance of credit loss allowance | boi_met:mi3 | xbrli:monetaryItemType | instant | N/A | N/A | boi_CS:x1 | N/A | N/A | N/A | N/A | N/A | N/A |
| r1.1 | A. Balance sheet credit to the public/Past year2 | boi_met:pd511 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x28 | boi_SE:x16 | N/A | N/A |
| r1.2 | A. Balance sheet credit to the public/Minimum | boi_met:pd512 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x29 | boi_SE:x16 | N/A | N/A |
| r1.3 | A. Balance sheet credit to the public/Maximum | boi_met:pd513 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x29 | boi_SE:x16 | N/A | N/A |
| r1.4 | A. Balance sheet credit to the public/Average | boi_met:pd511 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x29 | boi_SE:x16 | N/A | N/A |
| r1.5 | A. Balance sheet credit to the public/Decision6 | boi_met:pd514 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | N/A | boi_SE:x16 | N/A | N/A |
| r1.6 | A. Balance sheet credit to the public/Adjustments7 | boi_met:pd515 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | N/A | boi_SE:x16 | N/A | N/A |
| r1.7 | A. Balance sheet credit to the public/Allowance coefficient1 | boi_met:pd510 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | N/A | boi_SE:x16 | N/A | N/A |
| r1.8 | A. Balance sheet credit to the public/Recorded debt balance2 | boi_met:mi468 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | N/A | N/A | boi_SE:x16 | N/A | N/A |
| r1.9 | A. Balance sheet credit to the public/Balance of credit loss allowance | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | N/A | N/A | boi_SE:x16 | N/A | N/A |
| 1.1 | Impaired/Past year2 | boi_met:pd511 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x28 | boi_SE:x16 | boi_ST:x74 | boi_ST:x3 |
| 1.2 | Impaired/Minimum | boi_met:pd512 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x29 | boi_SE:x16 | boi_ST:x74 | boi_ST:x3 |
| 1.3 | Impaired/Maximum | boi_met:pd513 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x29 | boi_SE:x16 | boi_ST:x74 | boi_ST:x3 |
| 1.4 | Impaired/Average | boi_met:pd511 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x29 | boi_SE:x16 | boi_ST:x74 | boi_ST:x3 |
| 1.5 | Impaired/Decision6 | boi_met:pd514 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | N/A | boi_SE:x16 | boi_ST:x74 | boi_ST:x3 |
| 1.6 | Impaired/Adjustments7 | boi_met:pd515 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | N/A | boi_SE:x16 | boi_ST:x74 | boi_ST:x3 |
| 1.7 | Impaired/Allowance coefficient1 | boi_met:pd510 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | N/A | boi_SE:x16 | boi_ST:x74 | boi_ST:x3 |
| 1.8 | Impaired/Recorded debt balance2 | boi_met:mi468 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | N/A | N/A | boi_SE:x16 | boi_ST:x74 | boi_ST:x3 |
| 1.9 | Impaired/Balance of credit loss allowance | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | N/A | N/A | boi_SE:x16 | boi_ST:x74 | boi_ST:x3 |
| 2.1 | Special supervision and substandard/Past year2 | boi_met:pd511 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x28 | boi_SE:x16 | boi_ST:x74 | boi_ST:x4 |
| 2.2 | Special supervision and substandard/Minimum | boi_met:pd512 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x29 | boi_SE:x16 | boi_ST:x74 | boi_ST:x4 |
| 2.3 | Special supervision and substandard/Maximum | boi_met:pd513 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x29 | boi_SE:x16 | boi_ST:x74 | boi_ST:x4 |
| 2.4 | Special supervision and substandard/Average | boi_met:pd511 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x29 | boi_SE:x16 | boi_ST:x74 | boi_ST:x4 |
| 2.5 | Special supervision and substandard/Decision6 | boi_met:pd514 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | N/A | boi_SE:x16 | boi_ST:x74 | boi_ST:x4 |
| 2.6 | Special supervision and substandard/Adjustments7 | boi_met:pd515 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | N/A | boi_SE:x16 | boi_ST:x74 | boi_ST:x4 |
| 2.7 | Special supervision and substandard/Allowance coefficient1 | boi_met:pd510 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | N/A | boi_SE:x16 | boi_ST:x74 | boi_ST:x4 |
| 2.8 | Special supervision and substandard/Recorded debt balance2 | boi_met:mi468 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | N/A | N/A | boi_SE:x16 | boi_ST:x74 | boi_ST:x4 |
| 2.9 | Special supervision and substandard/Balance of credit loss allowance | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | N/A | N/A | boi_SE:x16 | boi_ST:x74 | boi_ST:x4 |
| 3.1 | Not problematic/Past year2 | boi_met:pd511 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x28 | boi_SE:x16 | boi_ST:x74 | boi_ST:x1 |
| 3.2 | Not problematic/Minimum | boi_met:pd512 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x29 | boi_SE:x16 | boi_ST:x74 | boi_ST:x1 |
| 3.3 | Not problematic/Maximum | boi_met:pd513 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x29 | boi_SE:x16 | boi_ST:x74 | boi_ST:x1 |
| 3.4 | Not problematic/Average | boi_met:pd511 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x29 | boi_SE:x16 | boi_ST:x74 | boi_ST:x1 |
| 3.5 | Not problematic/Decision6 | boi_met:pd514 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | N/A | boi_SE:x16 | boi_ST:x74 | boi_ST:x1 |
| 3.6 | Not problematic/Adjustments7 | boi_met:pd515 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | N/A | boi_SE:x16 | boi_ST:x74 | boi_ST:x1 |
| 3.7 | Not problematic/Allowance coefficient1 | boi_met:pd510 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | N/A | boi_SE:x16 | boi_ST:x74 | boi_ST:x1 |
| 3.8 | Not problematic/Recorded debt balance2 | boi_met:mi468 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | N/A | N/A | boi_SE:x16 | boi_ST:x74 | boi_ST:x1 |
| 3.9 | Not problematic/Balance of credit loss allowance | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | N/A | N/A | boi_SE:x16 | boi_ST:x74 | boi_ST:x1 |
| 4.1 | Total excluding loans for housing4/Past year2 | boi_met:pd511 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x28 | boi_SE:x16 | boi_ST:x74 | N/A |
| 4.2 | Total excluding loans for housing4/Minimum | boi_met:pd512 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x29 | boi_SE:x16 | boi_ST:x74 | N/A |
| 4.3 | Total excluding loans for housing4/Maximum | boi_met:pd513 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x29 | boi_SE:x16 | boi_ST:x74 | N/A |
| 4.4 | Total excluding loans for housing4/Average | boi_met:pd511 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x29 | boi_SE:x16 | boi_ST:x74 | N/A |
| 4.5 | Total excluding loans for housing4/Decision6 | boi_met:pd514 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | N/A | boi_SE:x16 | boi_ST:x74 | N/A |
| 4.6 | Total excluding loans for housing4/Adjustments7 | boi_met:pd515 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | N/A | boi_SE:x16 | boi_ST:x74 | N/A |
| 4.7 | Total excluding loans for housing4/Allowance coefficient1 | boi_met:pd510 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | N/A | boi_SE:x16 | boi_ST:x74 | N/A |
| 4.8 | Total excluding loans for housing4/Recorded debt balance2 | boi_met:mi468 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | N/A | N/A | boi_SE:x16 | boi_ST:x74 | N/A |
| 4.9 | Total excluding loans for housing4/Balance of credit loss allowance | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | N/A | N/A | boi_SE:x16 | boi_ST:x74 | N/A |
| 5.1 | Loans for housing/Past year2 | boi_met:pd511 | num:percentItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x28 | boi_SE:x16 | boi_ST:x96 | N/A |
| 5.2 | Loans for housing/Minimum | boi_met:pd512 | num:percentItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x29 | boi_SE:x16 | boi_ST:x96 | N/A |
| 5.3 | Loans for housing/Maximum | boi_met:pd513 | num:percentItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x29 | boi_SE:x16 | boi_ST:x96 | N/A |
| 5.4 | Loans for housing/Average | boi_met:pd511 | num:percentItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x29 | boi_SE:x16 | boi_ST:x96 | N/A |
| 5.5 | Loans for housing/Decision6 | boi_met:pd514 | num:percentItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | N/A | boi_SE:x16 | boi_ST:x96 | N/A |
| 5.6 | Loans for housing/Adjustments7 | boi_met:pd515 | num:percentItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | N/A | boi_SE:x16 | boi_ST:x96 | N/A |
| 5.7 | Loans for housing/Allowance coefficient1 | boi_met:pd510 | num:percentItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | N/A | boi_SE:x16 | boi_ST:x96 | N/A |
| 5.8 | Loans for housing/Recorded debt balance2 | boi_met:mi468 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CS:x1 | boi_MC:x8 | N/A | N/A | boi_SE:x16 | boi_ST:x96 | N/A |
| 5.9 | Loans for housing/Balance of credit loss allowance | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CS:x1 | boi_MC:x8 | N/A | N/A | boi_SE:x16 | boi_ST:x96 | N/A |
| 6.1 | Total/Past year2 | boi_met:pd511 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x28 | boi_SE:x16 | N/A | N/A |
| 6.2 | Total/Minimum | boi_met:pd512 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x29 | boi_SE:x16 | N/A | N/A |
| 6.3 | Total/Maximum | boi_met:pd513 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x29 | boi_SE:x16 | N/A | N/A |
| 6.4 | Total/Average | boi_met:pd511 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x29 | boi_SE:x16 | N/A | N/A |
| 6.5 | Total/Decision6 | boi_met:pd514 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | N/A | boi_SE:x16 | N/A | N/A |
| 6.6 | Total/Adjustments7 | boi_met:pd515 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | N/A | boi_SE:x16 | N/A | N/A |
| 6.7 | Total/Allowance coefficient1 | boi_met:pd510 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | N/A | boi_SE:x16 | N/A | N/A |
| 6.8 | Total/Recorded debt balance2 | boi_met:mi468 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | N/A | N/A | boi_SE:x16 | N/A | N/A |
| 6.9 | Total/Balance of credit loss allowance | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | N/A | N/A | boi_SE:x16 | N/A | N/A |
| r8.1 | B. Deposits at banks and credit to governments/Past year2 | boi_met:pd511 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x28 | boi_SE:x77 | N/A | N/A |
| r8.2 | B. Deposits at banks and credit to governments/Minimum | boi_met:pd512 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x29 | boi_SE:x77 | N/A | N/A |
| r8.3 | B. Deposits at banks and credit to governments/Maximum | boi_met:pd513 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x29 | boi_SE:x77 | N/A | N/A |
| r8.4 | B. Deposits at banks and credit to governments/Average | boi_met:pd511 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x29 | boi_SE:x77 | N/A | N/A |
| r8.5 | B. Deposits at banks and credit to governments/Decision6 | boi_met:pd514 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | N/A | boi_SE:x77 | N/A | N/A |
| r8.6 | B. Deposits at banks and credit to governments/Adjustments7 | boi_met:pd515 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | N/A | boi_SE:x77 | N/A | N/A |
| r8.7 | B. Deposits at banks and credit to governments/Allowance coefficient1 | boi_met:pd510 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | N/A | boi_SE:x77 | N/A | N/A |
| r8.8 | B. Deposits at banks and credit to governments/Recorded debt balance2 | boi_met:mi468 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | N/A | N/A | boi_SE:x77 | N/A | N/A |
| r8.9 | B. Deposits at banks and credit to governments/Balance of credit loss allowance | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | N/A | N/A | boi_SE:x77 | N/A | N/A |
| 7.1 | Impaired/Past year2 | boi_met:pd511 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x28 | boi_SE:x77 | N/A | boi_ST:x3 |
| 7.2 | Impaired/Minimum | boi_met:pd512 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x29 | boi_SE:x77 | N/A | boi_ST:x3 |
| 7.3 | Impaired/Maximum | boi_met:pd513 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x29 | boi_SE:x77 | N/A | boi_ST:x3 |
| 7.4 | Impaired/Average | boi_met:pd511 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x29 | boi_SE:x77 | N/A | boi_ST:x3 |
| 7.5 | Impaired/Decision6 | boi_met:pd514 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | N/A | boi_SE:x77 | N/A | boi_ST:x3 |
| 7.6 | Impaired/Adjustments7 | boi_met:pd515 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | N/A | boi_SE:x77 | N/A | boi_ST:x3 |
| 7.7 | Impaired/Allowance coefficient1 | boi_met:pd510 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | N/A | boi_SE:x77 | N/A | boi_ST:x3 |
| 7.8 | Impaired/Recorded debt balance2 | boi_met:mi468 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | N/A | N/A | boi_SE:x77 | N/A | boi_ST:x3 |
| 7.9 | Impaired/Balance of credit loss allowance | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | N/A | N/A | boi_SE:x77 | N/A | boi_ST:x3 |
| 8.1 | Special supervision and substandard/Past year2 | boi_met:pd511 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x28 | boi_SE:x77 | N/A | boi_ST:x4 |
| 8.2 | Special supervision and substandard/Minimum | boi_met:pd512 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x29 | boi_SE:x77 | N/A | boi_ST:x4 |
| 8.3 | Special supervision and substandard/Maximum | boi_met:pd513 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x29 | boi_SE:x77 | N/A | boi_ST:x4 |
| 8.4 | Special supervision and substandard/Average | boi_met:pd511 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x29 | boi_SE:x77 | N/A | boi_ST:x4 |
| 8.5 | Special supervision and substandard/Decision6 | boi_met:pd514 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | N/A | boi_SE:x77 | N/A | boi_ST:x4 |
| 8.6 | Special supervision and substandard/Adjustments7 | boi_met:pd515 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | N/A | boi_SE:x77 | N/A | boi_ST:x4 |
| 8.7 | Special supervision and substandard/Allowance coefficient1 | boi_met:pd510 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | N/A | boi_SE:x77 | N/A | boi_ST:x4 |
| 8.8 | Special supervision and substandard/Recorded debt balance2 | boi_met:mi468 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | N/A | N/A | boi_SE:x77 | N/A | boi_ST:x4 |
| 8.9 | Special supervision and substandard/Balance of credit loss allowance | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | N/A | N/A | boi_SE:x77 | N/A | boi_ST:x4 |
| 9.1 | Not problematic/Past year2 | boi_met:pd511 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x28 | boi_SE:x77 | N/A | boi_ST:x1 |
| 9.2 | Not problematic/Minimum | boi_met:pd512 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x29 | boi_SE:x77 | N/A | boi_ST:x1 |
| 9.3 | Not problematic/Maximum | boi_met:pd513 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x29 | boi_SE:x77 | N/A | boi_ST:x1 |
| 9.4 | Not problematic/Average | boi_met:pd511 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x29 | boi_SE:x77 | N/A | boi_ST:x1 |
| 9.5 | Not problematic/Decision6 | boi_met:pd514 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | N/A | boi_SE:x77 | N/A | boi_ST:x1 |
| 9.6 | Not problematic/Adjustments7 | boi_met:pd515 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | N/A | boi_SE:x77 | N/A | boi_ST:x1 |
| 9.7 | Not problematic/Allowance coefficient1 | boi_met:pd510 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | N/A | boi_SE:x77 | N/A | boi_ST:x1 |
| 9.8 | Not problematic/Recorded debt balance2 | boi_met:mi468 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | N/A | N/A | boi_SE:x77 | N/A | boi_ST:x1 |
| 9.9 | Not problematic/Balance of credit loss allowance | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | N/A | N/A | boi_SE:x77 | N/A | boi_ST:x1 |
| 10.1 | Total/Past year2 | boi_met:pd511 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x28 | boi_SE:x77 | N/A | N/A |
| 10.2 | Total/Minimum | boi_met:pd512 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x29 | boi_SE:x77 | N/A | N/A |
| 10.3 | Total/Maximum | boi_met:pd513 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x29 | boi_SE:x77 | N/A | N/A |
| 10.4 | Total/Average | boi_met:pd511 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | boi_RP:x29 | boi_SE:x77 | N/A | N/A |
| 10.5 | Total/Decision6 | boi_met:pd514 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | N/A | boi_SE:x77 | N/A | N/A |
| 10.6 | Total/Adjustments7 | boi_met:pd515 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | N/A | boi_SE:x77 | N/A | N/A |
| 10.7 | Total/Allowance coefficient1 | boi_met:pd510 | num:percentItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | boi_MU:x1 | N/A | boi_SE:x77 | N/A | N/A |
| 10.8 | Total/Recorded debt balance2 | boi_met:mi468 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | N/A | N/A | boi_SE:x77 | N/A | N/A |
| 10.9 | Total/Balance of credit loss allowance | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | N/A | boi_CS:x1 | boi_MC:x8 | N/A | N/A | boi_SE:x77 | N/A | N/A |
| r13.1 | C. Off balance sheet credit instruments/Past year2 | boi_met:pd511 | num:percentItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | boi_MU:x1 | boi_RP:x28 | N/A | N/A | N/A |
| r13.2 | C. Off balance sheet credit instruments/Minimum | boi_met:pd512 | num:percentItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | boi_MU:x1 | boi_RP:x29 | N/A | N/A | N/A |
| r13.3 | C. Off balance sheet credit instruments/Maximum | boi_met:pd513 | num:percentItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | boi_MU:x1 | boi_RP:x29 | N/A | N/A | N/A |
| r13.4 | C. Off balance sheet credit instruments/Average | boi_met:pd511 | num:percentItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | boi_MU:x1 | boi_RP:x29 | N/A | N/A | N/A |
| r13.5 | C. Off balance sheet credit instruments/Decision6 | boi_met:pd514 | num:percentItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | boi_MU:x1 | N/A | N/A | N/A | N/A |
| r13.6 | C. Off balance sheet credit instruments/Adjustments7 | boi_met:pd515 | num:percentItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | boi_MU:x1 | N/A | N/A | N/A | N/A |
| r13.7 | C. Off balance sheet credit instruments/Allowance coefficient1 | boi_met:pd510 | num:percentItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | boi_MU:x1 | N/A | N/A | N/A | N/A |
| r13.8 | C. Off balance sheet credit instruments/Recorded debt balance2 | boi_met:mi468 | xbrli:monetaryItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | N/A | N/A | N/A | N/A | N/A |
| r13.9 | C. Off balance sheet credit instruments/Balance of credit loss allowance | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | N/A | N/A | N/A | N/A | N/A |
| 11.1 | Impaired/Past year2 | boi_met:pd511 | num:percentItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | boi_MU:x1 | boi_RP:x28 | N/A | N/A | boi_ST:x3 |
| 11.2 | Impaired/Minimum | boi_met:pd512 | num:percentItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | boi_MU:x1 | boi_RP:x29 | N/A | N/A | boi_ST:x3 |
| 11.3 | Impaired/Maximum | boi_met:pd513 | num:percentItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | boi_MU:x1 | boi_RP:x29 | N/A | N/A | boi_ST:x3 |
| 11.4 | Impaired/Average | boi_met:pd511 | num:percentItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | boi_MU:x1 | boi_RP:x29 | N/A | N/A | boi_ST:x3 |
| 11.5 | Impaired/Decision6 | boi_met:pd514 | num:percentItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | boi_MU:x1 | N/A | N/A | N/A | boi_ST:x3 |
| 11.6 | Impaired/Adjustments7 | boi_met:pd515 | num:percentItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | boi_MU:x1 | N/A | N/A | N/A | boi_ST:x3 |
| 11.7 | Impaired/Allowance coefficient1 | boi_met:pd510 | num:percentItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | boi_MU:x1 | N/A | N/A | N/A | boi_ST:x3 |
| 11.8 | Impaired/Recorded debt balance2 | boi_met:mi468 | xbrli:monetaryItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | N/A | N/A | N/A | N/A | boi_ST:x3 |
| 11.9 | Impaired/Balance of credit loss allowance | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | N/A | N/A | N/A | N/A | boi_ST:x3 |
| 12.1 | Special supervision and substandard/Past year2 | boi_met:pd511 | num:percentItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | boi_MU:x1 | boi_RP:x28 | N/A | N/A | boi_ST:x4 |
| 12.2 | Special supervision and substandard/Minimum | boi_met:pd512 | num:percentItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | boi_MU:x1 | boi_RP:x29 | N/A | N/A | boi_ST:x4 |
| 12.3 | Special supervision and substandard/Maximum | boi_met:pd513 | num:percentItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | boi_MU:x1 | boi_RP:x29 | N/A | N/A | boi_ST:x4 |
| 12.4 | Special supervision and substandard/Average | boi_met:pd511 | num:percentItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | boi_MU:x1 | boi_RP:x29 | N/A | N/A | boi_ST:x4 |
| 12.5 | Special supervision and substandard/Decision6 | boi_met:pd514 | num:percentItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | boi_MU:x1 | N/A | N/A | N/A | boi_ST:x4 |
| 12.6 | Special supervision and substandard/Adjustments7 | boi_met:pd515 | num:percentItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | boi_MU:x1 | N/A | N/A | N/A | boi_ST:x4 |
| 12.7 | Special supervision and substandard/Allowance coefficient1 | boi_met:pd510 | num:percentItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | boi_MU:x1 | N/A | N/A | N/A | boi_ST:x4 |
| 12.8 | Special supervision and substandard/Recorded debt balance2 | boi_met:mi468 | xbrli:monetaryItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | N/A | N/A | N/A | N/A | boi_ST:x4 |
| 12.9 | Special supervision and substandard/Balance of credit loss allowance | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | N/A | N/A | N/A | N/A | boi_ST:x4 |
| 13.1 | Not problematic/Past year2 | boi_met:pd511 | num:percentItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | boi_MU:x1 | boi_RP:x28 | N/A | N/A | boi_ST:x1 |
| 13.2 | Not problematic/Minimum | boi_met:pd512 | num:percentItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | boi_MU:x1 | boi_RP:x29 | N/A | N/A | boi_ST:x1 |
| 13.3 | Not problematic/Maximum | boi_met:pd513 | num:percentItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | boi_MU:x1 | boi_RP:x29 | N/A | N/A | boi_ST:x1 |
| 13.4 | Not problematic/Average | boi_met:pd511 | num:percentItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | boi_MU:x1 | boi_RP:x29 | N/A | N/A | boi_ST:x1 |
| 13.5 | Not problematic/Decision6 | boi_met:pd514 | num:percentItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | boi_MU:x1 | N/A | N/A | N/A | boi_ST:x1 |
| 13.6 | Not problematic/Adjustments7 | boi_met:pd515 | num:percentItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | boi_MU:x1 | N/A | N/A | N/A | boi_ST:x1 |
| 13.7 | Not problematic/Allowance coefficient1 | boi_met:pd510 | num:percentItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | boi_MU:x1 | N/A | N/A | N/A | boi_ST:x1 |
| 13.8 | Not problematic/Recorded debt balance2 | boi_met:mi468 | xbrli:monetaryItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | N/A | N/A | N/A | N/A | boi_ST:x1 |
| 13.9 | Not problematic/Balance of credit loss allowance | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | N/A | N/A | N/A | N/A | boi_ST:x1 |
| 14.1 | Total/Past year2 | boi_met:pd511 | num:percentItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | boi_MU:x1 | boi_RP:x28 | N/A | N/A | N/A |
| 14.2 | Total/Minimum | boi_met:pd512 | num:percentItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | boi_MU:x1 | boi_RP:x29 | N/A | N/A | N/A |
| 14.3 | Total/Maximum | boi_met:pd513 | num:percentItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | boi_MU:x1 | boi_RP:x29 | N/A | N/A | N/A |
| 14.4 | Total/Average | boi_met:pd511 | num:percentItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | boi_MU:x1 | boi_RP:x29 | N/A | N/A | N/A |
| 14.5 | Total/Decision6 | boi_met:pd514 | num:percentItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | boi_MU:x1 | N/A | N/A | N/A | N/A |
| 14.6 | Total/Adjustments7 | boi_met:pd515 | num:percentItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | boi_MU:x1 | N/A | N/A | N/A | N/A |
| 14.7 | Total/Allowance coefficient1 | boi_met:pd510 | num:percentItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | boi_MU:x1 | N/A | N/A | N/A | N/A |
| 14.8 | Total/Recorded debt balance2 | boi_met:mi468 | xbrli:monetaryItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | N/A | N/A | N/A | N/A | N/A |
| 14.9 | Total/Balance of credit loss allowance | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x8 | N/A | boi_CS:x1 | boi_MC:x65 | N/A | N/A | N/A | N/A | N/A |
| 15.1 | Total balance sheet and off balance sheet/Past year2 | boi_met:pd511 | num:percentItemType | instant | boi_BC:x28 | N/A | boi_CS:x1 | boi_MC:x704 | boi_MU:x1 | boi_RP:x28 | N/A | N/A | N/A |
| 15.2 | Total balance sheet and off balance sheet/Minimum | boi_met:pd512 | num:percentItemType | instant | boi_BC:x28 | N/A | boi_CS:x1 | boi_MC:x704 | boi_MU:x1 | boi_RP:x29 | N/A | N/A | N/A |
| 15.3 | Total balance sheet and off balance sheet/Maximum | boi_met:pd513 | num:percentItemType | instant | boi_BC:x28 | N/A | boi_CS:x1 | boi_MC:x704 | boi_MU:x1 | boi_RP:x29 | N/A | N/A | N/A |
| 15.4 | Total balance sheet and off balance sheet/Average | boi_met:pd511 | num:percentItemType | instant | boi_BC:x28 | N/A | boi_CS:x1 | boi_MC:x704 | boi_MU:x1 | boi_RP:x29 | N/A | N/A | N/A |
| 15.5 | Total balance sheet and off balance sheet/Decision6 | boi_met:pd514 | num:percentItemType | instant | boi_BC:x28 | N/A | boi_CS:x1 | boi_MC:x704 | boi_MU:x1 | N/A | N/A | N/A | N/A |
| 15.6 | Total balance sheet and off balance sheet/Adjustments7 | boi_met:pd515 | num:percentItemType | instant | boi_BC:x28 | N/A | boi_CS:x1 | boi_MC:x704 | boi_MU:x1 | N/A | N/A | N/A | N/A |
| 15.7 | Total balance sheet and off balance sheet/Allowance coefficient1 | boi_met:pd510 | num:percentItemType | instant | boi_BC:x28 | N/A | boi_CS:x1 | boi_MC:x704 | boi_MU:x1 | N/A | N/A | N/A | N/A |
| 15.8 | Total balance sheet and off balance sheet/Recorded debt balance2 | boi_met:mi468 | xbrli:monetaryItemType | instant | boi_BC:x28 | N/A | boi_CS:x1 | boi_MC:x704 | N/A | N/A | N/A | N/A | N/A |
| 15.9 | Total balance sheet and off balance sheet/Balance of credit loss allowance | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x28 | N/A | boi_CS:x1 | boi_MC:x704 | N/A | N/A | N/A | N/A | N/A |