| r0.1 | label_boi_a2/Balance | boi_met:mi204 | xbrli:monetaryItemType | instant | boi_BC:x8 | boi_CS:x2 | N/A | boi_RP:x24 |
| r0.2 | label_boi_a2/Allowance | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x8 | boi_CS:x2 | N/A | boi_RP:x24 |
| 1.1 | Documentary Credit/Balance | boi_met:mi204 | xbrli:monetaryItemType | instant | boi_BC:x8 | boi_CS:x2 | boi_MC:x70 | boi_RP:x24 |
| 1.2 | Documentary Credit/Allowance | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x8 | boi_CS:x2 | boi_MC:x70 | boi_RP:x24 |
| 2.1 | Credit Gaurantees/Balance | boi_met:mi204 | xbrli:monetaryItemType | instant | boi_BC:x8 | boi_CS:x2 | boi_MC:x66 | boi_RP:x24 |
| 2.2 | Credit Gaurantees/Allowance | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x8 | boi_CS:x2 | boi_MC:x66 | boi_RP:x24 |
| 3.1 | Of which: Guarantees for debt balances deriving from credit card transactions/Balance | boi_met:mi204 | xbrli:monetaryItemType | instant | boi_BC:x8 | boi_CS:x2 | boi_MC:x506 | boi_RP:x24 |
| 3.2 | Of which: Guarantees for debt balances deriving from credit card transactions/Allowance | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x8 | boi_CS:x2 | boi_MC:x506 | boi_RP:x24 |
| 4.1 | Guarantees to purchasers of homes/Balance | boi_met:mi204 | xbrli:monetaryItemType | instant | boi_BC:x8 | boi_CS:x2 | boi_MC:x67 | boi_RP:x24 |
| 4.2 | Guarantees to purchasers of homes/Allowance | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x8 | boi_CS:x2 | boi_MC:x67 | boi_RP:x24 |
| 5.1 | Other guarantees and liabilities/Balance | boi_met:mi204 | xbrli:monetaryItemType | instant | boi_BC:x8 | boi_CS:x2 | boi_MC:x507 | boi_RP:x24 |
| 5.2 | Other guarantees and liabilities/Allowance | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x8 | boi_CS:x2 | boi_MC:x507 | boi_RP:x24 |
| 6.1 | Unutilized credit facilities for card credits/Balance | boi_met:mi204 | xbrli:monetaryItemType | instant | boi_BC:x8 | boi_CS:x2 | boi_MC:x74 | boi_RP:x24 |
| 6.2 | Unutilized credit facilities for card credits/Allowance | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x8 | boi_CS:x2 | boi_MC:x74 | boi_RP:x24 |
| 7.1 | Unutilized revolving overdraft and other on-demand credit facilities/Balance | boi_met:mi204 | xbrli:monetaryItemType | instant | boi_BC:x8 | boi_CS:x2 | boi_MC:x75 | boi_RP:x24 |
| 7.2 | Unutilized revolving overdraft and other on-demand credit facilities/Allowance | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x8 | boi_CS:x2 | boi_MC:x75 | boi_RP:x24 |
| 8.1 | Irrevocable commitments to grant credit which has been approved but not yet drawn/Balance | boi_met:mi204 | xbrli:monetaryItemType | instant | boi_BC:x8 | boi_CS:x2 | boi_MC:x77 | boi_RP:x24 |
| 8.2 | Irrevocable commitments to grant credit which has been approved but not yet drawn/Allowance | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x8 | boi_CS:x2 | boi_MC:x77 | boi_RP:x24 |
| 9.1 | Liabilities for the issue of guarantees/Balance | boi_met:mi204 | xbrli:monetaryItemType | instant | boi_BC:x8 | boi_CS:x2 | boi_MC:x76 | boi_RP:x24 |
| 9.2 | Liabilities for the issue of guarantees/Allowance | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x8 | boi_CS:x2 | boi_MC:x76 | boi_RP:x24 |
| 10.1 | Total/Balance | boi_met:mi204 | xbrli:monetaryItemType | instant | boi_BC:x8 | boi_CS:x2 | boi_MC:x65 | boi_RP:x24 |
| 10.2 | Total/Allowance | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x8 | boi_CS:x2 | boi_MC:x65 | boi_RP:x24 |