| r0.1 | label_boi_a2/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r0.2 | label_boi_a2/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r0.3 | label_boi_a2/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r0.4 | label_boi_a2/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r0.5 | label_boi_a2/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r0.6 | label_boi_a2/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r0.7 | label_boi_a2/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r1.1 | Bonds to maturity/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| r1.2 | Bonds to maturity/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| r1.3 | Bonds to maturity/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| r1.4 | Bonds to maturity/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| r1.5 | Bonds to maturity/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| r1.6 | Bonds to maturity/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| r1.7 | Bonds to maturity/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 1.1 | Israel Government/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 1.2 | Israel Government/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 1.3 | Israel Government/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 1.4 | Israel Government/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 1.5 | Israel Government/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 1.6 | Israel Government/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 1.7 | Israel Government/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 2.1 | Foreign governments/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 2.2 | Foreign governments/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 2.3 | Foreign governments/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 2.4 | Foreign governments/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 2.5 | Foreign governments/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 2.6 | Foreign governments/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 2.7 | Foreign governments/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 3.1 | Financial institutions in Israel/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 3.2 | Financial institutions in Israel/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 3.3 | Financial institutions in Israel/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 3.4 | Financial institutions in Israel/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 3.5 | Financial institutions in Israel/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 3.6 | Financial institutions in Israel/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 3.7 | Financial institutions in Israel/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 4.1 | Foreign financial institutions/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 4.2 | Foreign financial institutions/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 4.3 | Foreign financial institutions/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 4.4 | Foreign financial institutions/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 4.5 | Foreign financial institutions/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 4.6 | Foreign financial institutions/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 4.7 | Foreign financial institutions/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 5.1 | Asset-backed or mortgage-backed/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x5 | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 5.2 | Asset-backed or mortgage-backed/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x5 | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 5.3 | Asset-backed or mortgage-backed/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x5 | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 5.4 | Asset-backed or mortgage-backed/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x5 | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 5.5 | Asset-backed or mortgage-backed/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x5 | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 5.6 | Asset-backed or mortgage-backed/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x5 | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 5.7 | Asset-backed or mortgage-backed/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x5 | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 6.1 | Others, Israel/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 6.2 | Others, Israel/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 6.3 | Others, Israel/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 6.4 | Others, Israel/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 6.5 | Others, Israel/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 6.6 | Others, Israel/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 6.7 | Others, Israel/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 7.1 | Others, foreign/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 7.2 | Others, foreign/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 7.3 | Others, foreign/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 7.4 | Others, foreign/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 7.5 | Others, foreign/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 7.6 | Others, foreign/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 7.7 | Others, foreign/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 8.1 | Total bonds to maturity/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 8.2 | Total bonds to maturity/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 8.3 | Total bonds to maturity/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 8.4 | Total bonds to maturity/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 8.5 | Total bonds to maturity/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 8.6 | Total bonds to maturity/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 8.7 | Total bonds to maturity/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| r10.1 | Bonds available for sale/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| r10.2 | Bonds available for sale/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| r10.3 | Bonds available for sale/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| r10.4 | Bonds available for sale/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| r10.5 | Bonds available for sale/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| r10.6 | Bonds available for sale/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| r10.7 | Bonds available for sale/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 9.1 | Israel Government/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 9.2 | Israel Government/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 9.3 | Israel Government/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 9.4 | Israel Government/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 9.5 | Israel Government/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 9.6 | Israel Government/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 9.7 | Israel Government/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 10.1 | Foreign governments/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 10.2 | Foreign governments/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 10.3 | Foreign governments/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 10.4 | Foreign governments/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 10.5 | Foreign governments/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 10.6 | Foreign governments/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 10.7 | Foreign governments/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 11.1 | Financial institutions in Israel/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 11.2 | Financial institutions in Israel/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 11.3 | Financial institutions in Israel/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 11.4 | Financial institutions in Israel/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 11.5 | Financial institutions in Israel/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 11.6 | Financial institutions in Israel/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 11.7 | Financial institutions in Israel/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 12.1 | Foreign financial institutions/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 12.2 | Foreign financial institutions/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 12.3 | Foreign financial institutions/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 12.4 | Foreign financial institutions/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 12.5 | Foreign financial institutions/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 12.6 | Foreign financial institutions/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 12.7 | Foreign financial institutions/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 13.1 | Asset-backed or mortgage-backed/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x5 | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 13.2 | Asset-backed or mortgage-backed/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x5 | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 13.3 | Asset-backed or mortgage-backed/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x5 | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 13.4 | Asset-backed or mortgage-backed/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x5 | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 13.5 | Asset-backed or mortgage-backed/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x5 | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 13.6 | Asset-backed or mortgage-backed/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x5 | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 13.7 | Asset-backed or mortgage-backed/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x5 | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 14.1 | Others, Israel/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 14.2 | Others, Israel/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 14.3 | Others, Israel/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 14.4 | Others, Israel/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 14.5 | Others, Israel/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 14.6 | Others, Israel/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 14.7 | Others, Israel/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 15.1 | Others, foreign/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 15.2 | Others, foreign/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 15.3 | Others, foreign/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 15.4 | Others, foreign/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 15.5 | Others, foreign/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 15.6 | Others, foreign/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 15.7 | Others, foreign/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 16.1 | Total bonds available for sale/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 16.2 | Total bonds available for sale/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 16.3 | Total bonds available for sale/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 16.4 | Total bonds available for sale/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 16.5 | Total bonds available for sale/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 16.6 | Total bonds available for sale/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 16.7 | Total bonds available for sale/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 17.1 | Non trade shares/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x30 | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 17.2 | Non trade shares/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x30 | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 17.3 | Non trade shares/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x30 | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 17.4 | Non trade shares/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x30 | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 17.5 | Non trade shares/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x30 | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 17.6 | Non trade shares/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x30 | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 17.7 | Non trade shares/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x30 | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 18.1 | Of which: Shares at cost/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x31 | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 18.2 | Of which: Shares at cost/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x31 | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 18.3 | Of which: Shares at cost/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x31 | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 18.4 | Of which: Shares at cost/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x31 | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 18.5 | Of which: Shares at cost/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x31 | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 18.6 | Of which: Shares at cost/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x31 | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 18.7 | Of which: Shares at cost/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x31 | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 19.1 | Total non trade securities/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 19.2 | Total non trade securities/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 19.3 | Total non trade securities/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 19.4 | Total non trade securities/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 19.5 | Total non trade securities/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 19.6 | Total non trade securities/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 19.7 | Total non trade securities/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| r22.1 | Securities for trading/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| r22.2 | Securities for trading/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| r22.3 | Securities for trading/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| r22.4 | Securities for trading/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| r22.5 | Securities for trading/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| r22.6 | Securities for trading/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| r22.7 | Securities for trading/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 20.1 | Israel Government/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 20.2 | Israel Government/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 20.3 | Israel Government/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 20.4 | Israel Government/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 20.5 | Israel Government/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 20.6 | Israel Government/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 20.7 | Israel Government/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 21.1 | Foreign governments/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 21.2 | Foreign governments/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 21.3 | Foreign governments/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 21.4 | Foreign governments/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 21.5 | Foreign governments/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 21.6 | Foreign governments/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 21.7 | Foreign governments/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 22.1 | Financial institutions in Israel/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 22.2 | Financial institutions in Israel/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 22.3 | Financial institutions in Israel/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 22.4 | Financial institutions in Israel/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 22.5 | Financial institutions in Israel/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 22.6 | Financial institutions in Israel/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 22.7 | Financial institutions in Israel/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 23.1 | Foreign financial institutions/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 23.2 | Foreign financial institutions/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 23.3 | Foreign financial institutions/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 23.4 | Foreign financial institutions/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 23.5 | Foreign financial institutions/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 23.6 | Foreign financial institutions/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 23.7 | Foreign financial institutions/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 24.1 | Asset-backed or mortgage-backed/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x5 | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 24.2 | Asset-backed or mortgage-backed/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x5 | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 24.3 | Asset-backed or mortgage-backed/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x5 | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 24.4 | Asset-backed or mortgage-backed/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x5 | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 24.5 | Asset-backed or mortgage-backed/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x5 | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 24.6 | Asset-backed or mortgage-backed/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x5 | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 24.7 | Asset-backed or mortgage-backed/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x5 | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 25.1 | Others, Israel/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 25.2 | Others, Israel/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 25.3 | Others, Israel/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 25.4 | Others, Israel/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 25.5 | Others, Israel/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 25.6 | Others, Israel/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 25.7 | Others, Israel/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 26.1 | Others, foreign/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 26.2 | Others, foreign/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 26.3 | Others, foreign/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 26.4 | Others, foreign/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 26.5 | Others, foreign/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 26.6 | Others, foreign/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 26.7 | Others, foreign/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 27.1 | Total bonds for trading/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 27.2 | Total bonds for trading/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 27.3 | Total bonds for trading/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 27.4 | Total bonds for trading/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 27.5 | Total bonds for trading/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 27.6 | Total bonds for trading/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 27.7 | Total bonds for trading/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 28.1 | Total shares for trading/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x30 | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 28.2 | Total shares for trading/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x30 | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 28.3 | Total shares for trading/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x30 | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 28.4 | Total shares for trading/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x30 | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 28.5 | Total shares for trading/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x30 | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 28.6 | Total shares for trading/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x30 | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 28.7 | Total shares for trading/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x30 | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 29.1 | Of which: Shares at cost/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x31 | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 29.2 | Of which: Shares at cost/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x31 | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 29.3 | Of which: Shares at cost/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x31 | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 29.4 | Of which: Shares at cost/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x31 | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 29.5 | Of which: Shares at cost/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x31 | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 29.6 | Of which: Shares at cost/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x31 | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 29.7 | Of which: Shares at cost/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x31 | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 30.1 | Total securities for trading/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 30.2 | Total securities for trading/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 30.3 | Total securities for trading/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 30.4 | Total securities for trading/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 30.5 | Total securities for trading/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 30.6 | Total securities for trading/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 30.7 | Total securities for trading/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 31.1 | Of which: Securities classified for trading under Section 20/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | boi_PL:x3 | boi_RP:x24 | N/A | N/A | N/A |
| 31.2 | Of which: Securities classified for trading under Section 20/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | boi_PL:x3 | boi_RP:x24 | N/A | N/A | N/A |
| 31.3 | Of which: Securities classified for trading under Section 20/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | boi_PL:x3 | boi_RP:x24 | N/A | N/A | N/A |
| 31.4 | Of which: Securities classified for trading under Section 20/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | boi_PL:x3 | boi_RP:x24 | N/A | N/A | N/A |
| 31.5 | Of which: Securities classified for trading under Section 20/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | boi_PL:x3 | boi_RP:x24 | N/A | N/A | N/A |
| 31.6 | Of which: Securities classified for trading under Section 20/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | boi_PL:x3 | boi_RP:x24 | N/A | N/A | N/A |
| 31.7 | Of which: Securities classified for trading under Section 20/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | boi_PL:x3 | boi_RP:x24 | N/A | N/A | N/A |
| 32.1 | Total securities*/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 32.2 | Total securities*/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 32.3 | Total securities*/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 32.4 | Total securities*/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 32.5 | Total securities*/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 32.6 | Total securities*/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 32.7 | Total securities*/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 33.1 | Shares at cost (with no available fair value)/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x31 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 33.2 | Shares at cost (with no available fair value)/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x31 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 33.3 | Shares at cost (with no available fair value)/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x31 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 33.4 | Shares at cost (with no available fair value)/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x31 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 33.5 | Shares at cost (with no available fair value)/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x31 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 33.6 | Shares at cost (with no available fair value)/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x31 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 33.7 | Shares at cost (with no available fair value)/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x31 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r37.1 | *Of which: Bonds/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r37.2 | *Of which: Bonds/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r37.3 | *Of which: Bonds/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r37.4 | *Of which: Bonds/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r37.5 | *Of which: Bonds/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r37.6 | *Of which: Bonds/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r37.7 | *Of which: Bonds/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 34.1 | Included companies/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x26 | boi_MC:x15 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 34.2 | Included companies/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x26 | boi_MC:x15 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 34.3 | Included companies/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x26 | boi_MC:x15 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 34.4 | Included companies/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x26 | boi_MC:x15 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 34.5 | Included companies/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x26 | boi_MC:x15 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 34.6 | Included companies/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x26 | boi_MC:x15 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 34.7 | Included companies/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x26 | boi_MC:x15 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 35.1 | Consolidated companies/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x23 | boi_MC:x15 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 35.2 | Consolidated companies/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x23 | boi_MC:x15 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 35.3 | Consolidated companies/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x23 | boi_MC:x15 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 35.4 | Consolidated companies/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x23 | boi_MC:x15 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 35.5 | Consolidated companies/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x23 | boi_MC:x15 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 35.6 | Consolidated companies/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x23 | boi_MC:x15 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 35.7 | Consolidated companies/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x23 | boi_MC:x15 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 36.1 | Parent company or controlled by parent co./Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x28 | boi_MC:x15 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 36.2 | Parent company or controlled by parent co./Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x28 | boi_MC:x15 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 36.3 | Parent company or controlled by parent co./Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x28 | boi_MC:x15 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 36.4 | Parent company or controlled by parent co./Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x28 | boi_MC:x15 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 36.5 | Parent company or controlled by parent co./Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x28 | boi_MC:x15 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 36.6 | Parent company or controlled by parent co./Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x28 | boi_MC:x15 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 36.7 | Parent company or controlled by parent co./Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x28 | boi_MC:x15 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r41.1 | *Of which: Shares/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x30 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r41.2 | *Of which: Shares/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x30 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r41.3 | *Of which: Shares/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x30 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r41.4 | *Of which: Shares/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x30 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r41.5 | *Of which: Shares/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x30 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r41.6 | *Of which: Shares/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x30 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r41.7 | *Of which: Shares/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x30 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 37.1 | Included companies/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x26 | boi_MC:x30 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 37.2 | Included companies/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x26 | boi_MC:x30 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 37.3 | Included companies/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x26 | boi_MC:x30 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 37.4 | Included companies/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x26 | boi_MC:x30 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 37.5 | Included companies/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x26 | boi_MC:x30 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 37.6 | Included companies/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x26 | boi_MC:x30 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 37.7 | Included companies/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x26 | boi_MC:x30 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 38.1 | Consolidated companies/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x23 | boi_MC:x30 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 38.2 | Consolidated companies/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x23 | boi_MC:x30 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 38.3 | Consolidated companies/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x23 | boi_MC:x30 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 38.4 | Consolidated companies/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x23 | boi_MC:x30 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 38.5 | Consolidated companies/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x23 | boi_MC:x30 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 38.6 | Consolidated companies/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x23 | boi_MC:x30 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 38.7 | Consolidated companies/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x23 | boi_MC:x30 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 39.1 | Parent company or controlled by parent co./Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x28 | boi_MC:x30 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 39.2 | Parent company or controlled by parent co./Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x28 | boi_MC:x30 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 39.3 | Parent company or controlled by parent co./Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x28 | boi_MC:x30 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 39.4 | Parent company or controlled by parent co./Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x28 | boi_MC:x30 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 39.5 | Parent company or controlled by parent co./Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x28 | boi_MC:x30 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 39.6 | Parent company or controlled by parent co./Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x28 | boi_MC:x30 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 39.7 | Parent company or controlled by parent co./Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x28 | boi_MC:x30 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 40.1 | Problematic bonds accruing interest income/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_RP:x24 | N/A | boi_ST:x215 | N/A |
| 40.2 | Problematic bonds accruing interest income/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_RP:x24 | N/A | boi_ST:x215 | N/A |
| 40.3 | Problematic bonds accruing interest income/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_RP:x24 | N/A | boi_ST:x215 | N/A |
| 40.4 | Problematic bonds accruing interest income/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_RP:x24 | N/A | boi_ST:x215 | N/A |
| 40.5 | Problematic bonds accruing interest income/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_RP:x24 | N/A | boi_ST:x215 | N/A |
| 40.6 | Problematic bonds accruing interest income/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_RP:x24 | N/A | boi_ST:x215 | N/A |
| 40.7 | Problematic bonds accruing interest income/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_RP:x24 | N/A | boi_ST:x215 | N/A |
| 41.1 | Bonds that don't accruing interest income/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_RP:x24 | N/A | boi_ST:x212 | N/A |
| 41.2 | Bonds that don't accruing interest income/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_RP:x24 | N/A | boi_ST:x212 | N/A |
| 41.3 | Bonds that don't accruing interest income/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_RP:x24 | N/A | boi_ST:x212 | N/A |
| 41.4 | Bonds that don't accruing interest income/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_RP:x24 | N/A | boi_ST:x212 | N/A |
| 41.5 | Bonds that don't accruing interest income/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_RP:x24 | N/A | boi_ST:x212 | N/A |
| 41.6 | Bonds that don't accruing interest income/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_RP:x24 | N/A | boi_ST:x212 | N/A |
| 41.7 | Bonds that don't accruing interest income/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_RP:x24 | N/A | boi_ST:x212 | N/A |
| 42.1 | Accrued unimpaired bonds in arrears of 90 days or more/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_RP:x24 | N/A | boi_ST:x215 | boi_TI:x2 |
| 42.2 | Accrued unimpaired bonds in arrears of 90 days or more/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_RP:x24 | N/A | boi_ST:x215 | boi_TI:x2 |
| 42.3 | Accrued unimpaired bonds in arrears of 90 days or more/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_RP:x24 | N/A | boi_ST:x215 | boi_TI:x2 |
| 42.4 | Accrued unimpaired bonds in arrears of 90 days or more/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_RP:x24 | N/A | boi_ST:x215 | boi_TI:x2 |
| 42.5 | Accrued unimpaired bonds in arrears of 90 days or more/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_RP:x24 | N/A | boi_ST:x215 | boi_TI:x2 |
| 42.6 | Accrued unimpaired bonds in arrears of 90 days or more/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_RP:x24 | N/A | boi_ST:x215 | boi_TI:x2 |
| 42.7 | Accrued unimpaired bonds in arrears of 90 days or more/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_RP:x24 | N/A | boi_ST:x215 | boi_TI:x2 |
| 43.1 | Accrued unimpaired bonds in arrears of 30 to 89 days/Value in balance sheet | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_RP:x24 | N/A | boi_ST:x218 | boi_TI:x1 |
| 43.2 | Accrued unimpaired bonds in arrears of 30 to 89 days/Amortized cost (with shares at cost basis) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_RP:x24 | N/A | boi_ST:x218 | boi_TI:x1 |
| 43.3 | Accrued unimpaired bonds in arrears of 30 to 89 days/Allowance for credit losses | boi_met:mi3 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_RP:x24 | N/A | boi_ST:x218 | boi_TI:x1 |
| 43.4 | Accrued unimpaired bonds in arrears of 30 to 89 days/Unrealized profits from reconciliations to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_RP:x24 | N/A | boi_ST:x218 | boi_TI:x1 |
| 43.5 | Accrued unimpaired bonds in arrears of 30 to 89 days/Unrealized losses from reconciliations to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_RP:x24 | N/A | boi_ST:x218 | boi_TI:x1 |
| 43.6 | Accrued unimpaired bonds in arrears of 30 to 89 days/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_RP:x24 | N/A | boi_ST:x218 | boi_TI:x1 |
| 43.7 | Accrued unimpaired bonds in arrears of 30 to 89 days/Other profit and loss, hedging of forecast transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_RP:x24 | N/A | boi_ST:x218 | boi_TI:x1 |