| r0.1 | label_boi_a2/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r0.2 | label_boi_a2/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r0.3 | label_boi_a2/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r0.4 | label_boi_a2/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r0.5 | 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 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r0.6 | label_boi_a2/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r0.7 | label_boi_a2/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | N/A | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r0.8 | label_boi_a2/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | N/A | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r0.9 | label_boi_a2/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | N/A | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r0.10 | label_boi_a2/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | N/A | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r0.11 | label_boi_a2/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | N/A | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r0.12 | label_boi_a2/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | N/A | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r1.1 | Bonds to maturity/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| r1.2 | Bonds to maturity/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| r1.3 | Bonds to maturity/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| r1.4 | Bonds to maturity/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| r1.5 | Bonds to maturity/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| r1.6 | Bonds to maturity/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| r1.7 | Bonds to maturity/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | N/A | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| r1.8 | Bonds to maturity/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | N/A | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| r1.9 | Bonds to maturity/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | N/A | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| r1.10 | Bonds to maturity/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | N/A | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| r1.11 | Bonds to maturity/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | N/A | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| r1.12 | Bonds to maturity/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | N/A | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 1.1 | Israeli government/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 1.2 | Israeli government/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 1.3 | Israeli government/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 1.4 | Israeli government/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 1.5 | Israeli government/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 1.6 | Israeli government/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 1.7 | Israeli government/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 1.8 | Israeli government/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 1.9 | Israeli government/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 1.10 | Israeli government/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 1.11 | Israeli government/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 1.12 | Israeli government/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 2.1 | Foreign government/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 2.2 | Foreign government/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 2.3 | Foreign government/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 2.4 | Foreign government/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 2.5 | Foreign government/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 2.6 | Foreign government/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 2.7 | Foreign government/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 2.8 | Foreign government/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 2.9 | Foreign government/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 2.10 | Foreign government/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 2.11 | Foreign government/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 2.12 | Foreign government/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 3.1 | Israeli financial institutions/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 3.2 | Israeli financial institutions/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 3.3 | Israeli financial institutions/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 3.4 | Israeli financial institutions/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 3.5 | Israeli financial institutions/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 3.6 | Israeli financial institutions/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 3.7 | Israeli financial institutions/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 3.8 | Israeli financial institutions/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 3.9 | Israeli financial institutions/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 3.10 | Israeli financial institutions/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 3.11 | Israeli financial institutions/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 3.12 | Israeli financial institutions/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 4.1 | Foreign financial institutions/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 4.2 | Foreign financial institutions/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 4.3 | Foreign financial institutions/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 4.4 | Foreign financial institutions/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 4.5 | 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 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 4.6 | Foreign financial institutions/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 4.7 | Foreign financial institutions/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 4.8 | Foreign financial institutions/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 4.9 | Foreign financial institutions/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 4.10 | Foreign financial institutions/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 4.11 | Foreign financial institutions/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 4.12 | Foreign financial institutions/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 5.1 | Asset-backed or mortgage-backed/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x5 | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 5.2 | Asset-backed or mortgage-backed/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x5 | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 5.3 | Asset-backed or mortgage-backed/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x5 | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 5.4 | Asset-backed or mortgage-backed/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x5 | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 5.5 | 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 | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 5.6 | Asset-backed or mortgage-backed/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x5 | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 5.7 | Asset-backed or mortgage-backed/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x5 | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 5.8 | Asset-backed or mortgage-backed/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x5 | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 5.9 | Asset-backed or mortgage-backed/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x5 | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 5.10 | Asset-backed or mortgage-backed/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x5 | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 5.11 | Asset-backed or mortgage-backed/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x5 | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 5.12 | Asset-backed or mortgage-backed/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x5 | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 6.1 | Others, Israel/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 6.2 | Others, Israel/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 6.3 | Others, Israel/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 6.4 | Others, Israel/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 6.5 | Others, Israel/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 6.6 | Others, Israel/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 6.7 | Others, Israel/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 6.8 | Others, Israel/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 6.9 | Others, Israel/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 6.10 | Others, Israel/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 6.11 | Others, Israel/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 6.12 | Others, Israel/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 7.1 | Others, foreign/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 7.2 | Others, foreign/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 7.3 | Others, foreign/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 7.4 | Others, foreign/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 7.5 | Others, foreign/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 7.6 | Others, foreign/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 7.7 | Others, foreign/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 7.8 | Others, foreign/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 7.9 | Others, foreign/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 7.10 | Others, foreign/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 7.11 | Others, foreign/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 7.12 | Others, foreign/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x5 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 8.1 | Total bonds to maturity/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 8.2 | Total bonds to maturity/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 8.3 | Total bonds to maturity/Profit not yet realized from adjustment 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_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 8.4 | Total bonds to maturity/Losses not yet realized from adjustment 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_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 8.5 | 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 | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 8.6 | Total bonds to maturity/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 8.7 | Total bonds to maturity/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 8.8 | Total bonds to maturity/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 8.9 | Total bonds to maturity/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 8.10 | Total bonds to maturity/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 8.11 | Total bonds to maturity/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| 8.12 | Total bonds to maturity/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | N/A | boi_PL:x5 | boi_RP:x24 | N/A | N/A | N/A |
| r10.1 | Bonds available for sale/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| r10.2 | Bonds available for sale/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| r10.3 | Bonds available for sale/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| r10.4 | Bonds available for sale/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| r10.5 | Bonds available for sale/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| r10.6 | Bonds available for sale/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| r10.7 | Bonds available for sale/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | N/A | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| r10.8 | Bonds available for sale/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | N/A | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| r10.9 | Bonds available for sale/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | N/A | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| r10.10 | Bonds available for sale/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | N/A | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| r10.11 | Bonds available for sale/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | N/A | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| r10.12 | Bonds available for sale/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | N/A | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 9.1 | Israeli government/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 9.2 | Israeli government/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 9.3 | Israeli government/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 9.4 | Israeli government/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 9.5 | Israeli government/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 9.6 | Israeli government/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 9.7 | Israeli government/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 9.8 | Israeli government/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 9.9 | Israeli government/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 9.10 | Israeli government/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 9.11 | Israeli government/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 9.12 | Israeli government/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 10.1 | Foreign government/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 10.2 | Foreign government/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 10.3 | Foreign government/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 10.4 | Foreign government/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 10.5 | Foreign government/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 10.6 | Foreign government/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 10.7 | Foreign government/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 10.8 | Foreign government/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 10.9 | Foreign government/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 10.10 | Foreign government/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 10.11 | Foreign government/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 10.12 | Foreign government/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 11.1 | Israeli financial institutions/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 11.2 | Israeli financial institutions/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 11.3 | Israeli financial institutions/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 11.4 | Israeli financial institutions/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 11.5 | Israeli financial institutions/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 11.6 | Israeli financial institutions/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 11.7 | Israeli financial institutions/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 11.8 | Israeli financial institutions/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 11.9 | Israeli financial institutions/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 11.10 | Israeli financial institutions/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 11.11 | Israeli financial institutions/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 11.12 | Israeli financial institutions/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 12.1 | Foreign financial institutions/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 12.2 | Foreign financial institutions/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 12.3 | Foreign financial institutions/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 12.4 | Foreign financial institutions/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 12.5 | 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 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 12.6 | Foreign financial institutions/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 12.7 | Foreign financial institutions/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 12.8 | Foreign financial institutions/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 12.9 | Foreign financial institutions/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 12.10 | Foreign financial institutions/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 12.11 | Foreign financial institutions/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 12.12 | Foreign financial institutions/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 13.1 | Asset-backed or mortgage-backed/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x5 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 13.2 | Asset-backed or mortgage-backed/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x5 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 13.3 | Asset-backed or mortgage-backed/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x5 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 13.4 | Asset-backed or mortgage-backed/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x5 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 13.5 | 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 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 13.6 | Asset-backed or mortgage-backed/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x5 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 13.7 | Asset-backed or mortgage-backed/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x5 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 13.8 | Asset-backed or mortgage-backed/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x5 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 13.9 | Asset-backed or mortgage-backed/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x5 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 13.10 | Asset-backed or mortgage-backed/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x5 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 13.11 | Asset-backed or mortgage-backed/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x5 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 13.12 | Asset-backed or mortgage-backed/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x5 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 14.1 | Others, Israel/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 14.2 | Others, Israel/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 14.3 | Others, Israel/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 14.4 | Others, Israel/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 14.5 | Others, Israel/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 14.6 | Others, Israel/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 14.7 | Others, Israel/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 14.8 | Others, Israel/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 14.9 | Others, Israel/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 14.10 | Others, Israel/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 14.11 | Others, Israel/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 14.12 | Others, Israel/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 15.1 | Others, foreign/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 15.2 | Others, foreign/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 15.3 | Others, foreign/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 15.4 | Others, foreign/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 15.5 | Others, foreign/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 15.6 | Others, foreign/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 15.7 | Others, foreign/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 15.8 | Others, foreign/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 15.9 | Others, foreign/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 15.10 | Others, foreign/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 15.11 | Others, foreign/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 15.12 | Others, foreign/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x1 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 16.1 | Total bonds for sale/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 16.2 | Total bonds for sale/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 16.3 | Total bonds for sale/Profit not yet realized from adjustment 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_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 16.4 | Total bonds for sale/Losses not yet realized from adjustment 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_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 16.5 | Total bonds for sale/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 16.6 | Total bonds for sale/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 16.7 | Total bonds for sale/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 16.8 | Total bonds for sale/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 16.9 | Total bonds for sale/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 16.10 | Total bonds for sale/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 16.11 | Total bonds for sale/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 16.12 | Total bonds for sale/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| r19.1 | Investments in shares not held for trading/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| r19.2 | Investments in shares not held for trading/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| r19.3 | Investments in shares not held for trading/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| r19.4 | Investments in shares not held for trading/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| r19.5 | Investments in shares not held for trading/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| r19.6 | Investments in shares not held for trading/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| r19.7 | Investments in shares not held for trading/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | N/A | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| r19.8 | Investments in shares not held for trading/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | N/A | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| r19.9 | Investments in shares not held for trading/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | N/A | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| r19.10 | Investments in shares not held for trading/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | N/A | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| r19.11 | Investments in shares not held for trading/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | N/A | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| r19.12 | Investments in shares not held for trading/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | N/A | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 17.1 | Investments in shares not held for trading/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x30 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 17.2 | Investments in shares not held for trading/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x30 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 17.3 | Investments in shares not held for trading/Profit not yet realized from adjustment 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_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 17.4 | Investments in shares not held for trading/Losses not yet realized from adjustment 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_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 17.5 | Investments in shares not held for trading/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x30 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 17.6 | Investments in shares not held for trading/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x30 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 17.7 | Investments in shares not held for trading/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x30 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 17.8 | Investments in shares not held for trading/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x30 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 17.9 | Investments in shares not held for trading/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x30 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 17.10 | Investments in shares not held for trading/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x30 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 17.11 | Investments in shares not held for trading/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x30 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 17.12 | Investments in shares not held for trading/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x30 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 18.1 | Of which: Shares at cost/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x31 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 18.2 | Of which: Shares at cost/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x31 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 18.3 | Of which: Shares at cost/Profit not yet realized from adjustment 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_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 18.4 | Of which: Shares at cost/Losses not yet realized from adjustment 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_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 18.5 | 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 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 18.6 | Of which: Shares at cost/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x31 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 18.7 | Of which: Shares at cost/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x31 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 18.8 | Of which: Shares at cost/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x31 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 18.9 | Of which: Shares at cost/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x31 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 18.10 | Of which: Shares at cost/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x31 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 18.11 | Of which: Shares at cost/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x31 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 18.12 | Of which: Shares at cost/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x31 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 19.1 | Total securities not held for trade/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 19.2 | Total securities not held for trade/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 19.3 | Total securities not held for trade/Profit not yet realized from adjustment 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_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 19.4 | Total securities not held for trade/Losses not yet realized from adjustment 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_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 19.5 | Total securities not held for trade/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 19.6 | Total securities not held for trade/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 19.7 | Total securities not held for trade/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x29 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 19.8 | Total securities not held for trade/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x29 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 19.9 | Total securities not held for trade/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x29 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 19.10 | Total securities not held for trade/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x29 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 19.11 | Total securities not held for trade/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x29 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| 19.12 | Total securities not held for trade/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x29 | N/A | boi_PL:x1 | boi_RP:x24 | N/A | N/A | N/A |
| r23.1 | Trading securities/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| r23.2 | Trading securities/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| r23.3 | Trading securities/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| r23.4 | Trading securities/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| r23.5 | Trading securities/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| r23.6 | Trading securities/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | N/A | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| r23.7 | Trading securities/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | N/A | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| r23.8 | Trading securities/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | N/A | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| r23.9 | Trading securities/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | N/A | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| r23.10 | Trading securities/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | N/A | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| r23.11 | Trading securities/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | N/A | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| r23.12 | Trading securities/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | N/A | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 20.1 | Israeli government/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 20.2 | Israeli government/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 20.3 | Israeli government/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 20.4 | Israeli government/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 20.5 | Israeli government/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 20.6 | Israeli government/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 20.7 | Israeli government/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 20.8 | Israeli government/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 20.9 | Israeli government/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 20.10 | Israeli government/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 20.11 | Israeli government/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 20.12 | Israeli government/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 21.1 | Foreign government/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 21.2 | Foreign government/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 21.3 | Foreign government/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 21.4 | Foreign government/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 21.5 | Foreign government/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 21.6 | Foreign government/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 21.7 | Foreign government/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 21.8 | Foreign government/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 21.9 | Foreign government/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 21.10 | Foreign government/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 21.11 | Foreign government/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 21.12 | Foreign government/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x11 | N/A | N/A |
| 22.1 | Israeli financial institutions/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 22.2 | Israeli financial institutions/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 22.3 | Israeli financial institutions/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 22.4 | Israeli financial institutions/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 22.5 | Israeli financial institutions/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 22.6 | Israeli financial institutions/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 22.7 | Israeli financial institutions/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 22.8 | Israeli financial institutions/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 22.9 | Israeli financial institutions/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 22.10 | Israeli financial institutions/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 22.11 | Israeli financial institutions/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 22.12 | Israeli financial institutions/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 23.1 | Foreign financial institutions/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 23.2 | Foreign financial institutions/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 23.3 | Foreign financial institutions/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 23.4 | Foreign financial institutions/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 23.5 | 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 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 23.6 | Foreign financial institutions/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 23.7 | Foreign financial institutions/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 23.8 | Foreign financial institutions/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 23.9 | Foreign financial institutions/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 23.10 | Foreign financial institutions/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 23.11 | Foreign financial institutions/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 23.12 | Foreign financial institutions/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x9 | N/A | N/A |
| 24.1 | Asset-backed or mortgage-backed/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x5 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 24.2 | Asset-backed or mortgage-backed/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x5 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 24.3 | Asset-backed or mortgage-backed/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x5 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 24.4 | Asset-backed or mortgage-backed/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x5 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 24.5 | 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 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 24.6 | Asset-backed or mortgage-backed/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x5 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 24.7 | Asset-backed or mortgage-backed/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x5 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 24.8 | Asset-backed or mortgage-backed/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x5 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 24.9 | Asset-backed or mortgage-backed/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x5 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 24.10 | Asset-backed or mortgage-backed/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x5 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 24.11 | Asset-backed or mortgage-backed/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x5 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 24.12 | Asset-backed or mortgage-backed/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x5 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 25.1 | Others, Israel/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 25.2 | Others, Israel/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 25.3 | Others, Israel/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 25.4 | Others, Israel/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 25.5 | Others, Israel/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 25.6 | Others, Israel/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 25.7 | Others, Israel/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 25.8 | Others, Israel/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 25.9 | Others, Israel/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 25.10 | Others, Israel/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 25.11 | Others, Israel/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 25.12 | Others, Israel/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x1 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 26.1 | Others, foreign/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 26.2 | Others, foreign/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 26.3 | Others, foreign/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 26.4 | Others, foreign/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 26.5 | Others, foreign/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 26.6 | Others, foreign/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 26.7 | Others, foreign/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 26.8 | Others, foreign/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 26.9 | Others, foreign/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 26.10 | Others, foreign/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 26.11 | Others, foreign/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 26.12 | Others, foreign/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_GA:x2 | N/A | boi_MC:x16 | N/A | boi_PL:x2 | boi_RP:x24 | boi_SE:x69 | N/A | N/A |
| 27.1 | Total bonds and securities for traiding/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 27.2 | Total bonds and securities for traiding/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 27.3 | Total bonds and securities for traiding/Profit not yet realized from adjustment 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_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 27.4 | Total bonds and securities for traiding/Losses not yet realized from adjustment 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_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 27.5 | Total bonds and securities for traiding/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 27.6 | Total bonds and securities for traiding/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 27.7 | Total bonds and securities for traiding/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 27.8 | Total bonds and securities for traiding/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 27.9 | Total bonds and securities for traiding/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 27.10 | Total bonds and securities for traiding/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 27.11 | Total bonds and securities for traiding/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 27.12 | Total bonds and securities for traiding/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 28.1 | Total shares available for trading/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x30 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 28.2 | Total shares available for trading/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x30 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 28.3 | Total shares available for trading/Profit not yet realized from adjustment 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_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 28.4 | Total shares available for trading/Losses not yet realized from adjustment 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_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 28.5 | Total shares available for trading/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x30 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 28.6 | Total shares available for trading/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x30 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 28.7 | Total shares available for trading/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x30 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 28.8 | Total shares available for trading/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x30 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 28.9 | Total shares available for trading/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x30 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 28.10 | Total shares available for trading/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x30 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 28.11 | Total shares available for trading/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x30 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 28.12 | Total shares available for trading/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x30 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 29.1 | Of which: stocks at cost/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x31 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 29.2 | Of which: stocks at cost/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x31 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 29.3 | Of which: stocks at cost/Profit not yet realized from adjustment 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_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 29.4 | Of which: stocks at cost/Losses not yet realized from adjustment 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_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 29.5 | Of which: stocks at cost/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x31 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 29.6 | Of which: stocks at cost/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x31 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 29.7 | Of which: stocks at cost/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x31 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 29.8 | Of which: stocks at cost/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x31 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 29.9 | Of which: stocks at cost/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x31 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 29.10 | Of which: stocks at cost/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x31 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 29.11 | Of which: stocks at cost/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x31 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 29.12 | Of which: stocks at cost/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x31 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 30.1 | total trading securities/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 30.2 | total trading securities/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 30.3 | total trading securities/Profit not yet realized from adjustment 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_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 30.4 | total trading securities/Losses not yet realized from adjustment 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_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 30.5 | total trading 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_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 30.6 | total trading securities/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 30.7 | total trading securities/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x29 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 30.8 | total trading securities/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x29 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 30.9 | total trading securities/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x29 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 30.10 | total trading securities/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x29 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 30.11 | total trading securities/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x29 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 30.12 | total trading securities/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x29 | N/A | boi_PL:x2 | boi_RP:x24 | N/A | N/A | N/A |
| 31.1 | Of which: trade according to section 20/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | N/A | boi_PL:x3 | boi_RP:x24 | N/A | N/A | N/A |
| 31.2 | Of which: trade according to section 20/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | N/A | boi_PL:x3 | boi_RP:x24 | N/A | N/A | N/A |
| 31.3 | Of which: trade according to section 20/Profit not yet realized from adjustment 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_PL:x3 | boi_RP:x24 | N/A | N/A | N/A |
| 31.4 | Of which: trade according to section 20/Losses not yet realized from adjustment 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_PL:x3 | boi_RP:x24 | N/A | N/A | N/A |
| 31.5 | Of which: trade according to section 20/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | N/A | boi_PL:x3 | boi_RP:x24 | N/A | N/A | N/A |
| 31.6 | Of which: trade according to section 20/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | N/A | boi_PL:x3 | boi_RP:x24 | N/A | N/A | N/A |
| 31.7 | Of which: trade according to section 20/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x29 | N/A | boi_PL:x3 | boi_RP:x24 | N/A | N/A | N/A |
| 31.8 | Of which: trade according to section 20/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x29 | N/A | boi_PL:x3 | boi_RP:x24 | N/A | N/A | N/A |
| 31.9 | Of which: trade according to section 20/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x29 | N/A | boi_PL:x3 | boi_RP:x24 | N/A | N/A | N/A |
| 31.10 | Of which: trade according to section 20/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x29 | N/A | boi_PL:x3 | boi_RP:x24 | N/A | N/A | N/A |
| 31.11 | Of which: trade according to section 20/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x29 | N/A | boi_PL:x3 | boi_RP:x24 | N/A | N/A | N/A |
| 31.12 | Of which: trade according to section 20/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x29 | N/A | boi_PL:x3 | boi_RP:x24 | N/A | N/A | N/A |
| 32.1 | total securities/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 32.2 | total securities/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 32.3 | total securities/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 32.4 | total securities/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 32.5 | 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 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 32.6 | total securities/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x29 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 32.7 | total securities/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x29 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 32.8 | total securities/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x29 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 32.9 | total securities/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x29 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 32.10 | total securities/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x29 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 32.11 | total securities/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x29 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 32.12 | total securities/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x29 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 33.1 | Stocks at cost (no available fair value)/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x31 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 33.2 | Stocks at cost (no available fair value)/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x31 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 33.3 | Stocks at cost (no available fair value)/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x31 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 33.4 | Stocks at cost (no available fair value)/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x31 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 33.5 | Stocks at cost (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 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 33.6 | Stocks at cost (no available fair value)/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x31 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 33.7 | Stocks at cost (no available fair value)/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x31 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 33.8 | Stocks at cost (no available fair value)/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x31 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 33.9 | Stocks at cost (no available fair value)/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x31 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 33.10 | Stocks at cost (no available fair value)/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x31 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 33.11 | Stocks at cost (no available fair value)/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x31 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 33.12 | Stocks at cost (no available fair value)/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x31 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r38.1 | Of which: bonds/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r38.2 | Of which: bonds/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r38.3 | Of which: bonds/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r38.4 | Of which: bonds/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r38.5 | 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 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r38.6 | Of which: bonds/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r38.7 | Of which: bonds/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r38.8 | Of which: bonds/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r38.9 | Of which: bonds/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r38.10 | Of which: bonds/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r38.11 | Of which: bonds/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r38.12 | Of which: bonds/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 34.1 | Consolidated subsidiaries/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x26 | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 34.2 | Consolidated subsidiaries/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x26 | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 34.3 | Consolidated subsidiaries/Profit not yet realized from adjustment 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 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 34.4 | Consolidated subsidiaries/Losses not yet realized from adjustment 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 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 34.5 | Consolidated subsidiaries/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x26 | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 34.6 | Consolidated subsidiaries/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x26 | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 34.7 | Consolidated subsidiaries/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_IP:x26 | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 34.8 | Consolidated subsidiaries/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_IP:x26 | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 34.9 | Consolidated subsidiaries/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_IP:x26 | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 34.10 | Consolidated subsidiaries/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_IP:x26 | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 34.11 | Consolidated subsidiaries/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_IP:x26 | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 34.12 | Consolidated subsidiaries/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_IP:x26 | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 35.1 | Companies included on an equity basis/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x23 | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 35.2 | Companies included on an equity basis/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x23 | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 35.3 | Companies included on an equity basis/Profit not yet realized from adjustment 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 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 35.4 | Companies included on an equity basis/Losses not yet realized from adjustment 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 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 35.5 | Companies included on an equity basis/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x23 | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 35.6 | Companies included on an equity basis/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x23 | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 35.7 | Companies included on an equity basis/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_IP:x23 | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 35.8 | Companies included on an equity basis/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_IP:x23 | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 35.9 | Companies included on an equity basis/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_IP:x23 | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 35.10 | Companies included on an equity basis/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_IP:x23 | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 35.11 | Companies included on an equity basis/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_IP:x23 | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 35.12 | Companies included on an equity basis/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_IP:x23 | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 36.1 | Parent company or controlled by parent co./Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x28 | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 36.2 | Parent company or controlled by parent co./Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x28 | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 36.3 | Parent company or controlled by parent co./Profit not yet realized from adjustment 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 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 36.4 | Parent company or controlled by parent co./Losses not yet realized from adjustment 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 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 36.5 | 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 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 36.6 | Parent company or controlled by parent co./Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x28 | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 36.7 | Parent company or controlled by parent co./Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_IP:x28 | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 36.8 | Parent company or controlled by parent co./depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_IP:x28 | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 36.9 | Parent company or controlled by parent co./Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_IP:x28 | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 36.10 | Parent company or controlled by parent co./Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_IP:x28 | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 36.11 | Parent company or controlled by parent co./Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_IP:x28 | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 36.12 | Parent company or controlled by parent co./Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_IP:x28 | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r42.1 | Of which: stocks/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r42.2 | Of which: stocks/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r42.3 | Of which: stocks/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r42.4 | Of which: stocks/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r42.5 | Of which: stocks/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r42.6 | Of which: stocks/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r42.7 | Of which: stocks/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r42.8 | Of which: stocks/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r42.9 | Of which: stocks/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r42.10 | Of which: stocks/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r42.11 | Of which: stocks/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| r42.12 | Of which: stocks/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 37.1 | Consolidated subsidiaries/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x26 | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 37.2 | Consolidated subsidiaries/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x26 | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 37.3 | Consolidated subsidiaries/Profit not yet realized from adjustment 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 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 37.4 | Consolidated subsidiaries/Losses not yet realized from adjustment 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 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 37.5 | Consolidated subsidiaries/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x26 | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 37.6 | Consolidated subsidiaries/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x26 | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 37.7 | Consolidated subsidiaries/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_IP:x26 | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 37.8 | Consolidated subsidiaries/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_IP:x26 | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 37.9 | Consolidated subsidiaries/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_IP:x26 | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 37.10 | Consolidated subsidiaries/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_IP:x26 | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 37.11 | Consolidated subsidiaries/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_IP:x26 | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 37.12 | Consolidated subsidiaries/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_IP:x26 | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 38.1 | Companies included on an equity basis/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x23 | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 38.2 | Companies included on an equity basis/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x23 | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 38.3 | Companies included on an equity basis/Profit not yet realized from adjustment 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 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 38.4 | Companies included on an equity basis/Losses not yet realized from adjustment 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 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 38.5 | Companies included on an equity basis/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x23 | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 38.6 | Companies included on an equity basis/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x23 | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 38.7 | Companies included on an equity basis/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_IP:x23 | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 38.8 | Companies included on an equity basis/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_IP:x23 | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 38.9 | Companies included on an equity basis/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_IP:x23 | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 38.10 | Companies included on an equity basis/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_IP:x23 | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 38.11 | Companies included on an equity basis/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_IP:x23 | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 38.12 | Companies included on an equity basis/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_IP:x23 | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 39.1 | Parent company or controlled by parent co./Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x28 | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 39.2 | Parent company or controlled by parent co./Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x28 | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 39.3 | Parent company or controlled by parent co./Profit not yet realized from adjustment 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 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 39.4 | Parent company or controlled by parent co./Losses not yet realized from adjustment 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 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 39.5 | 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 | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 39.6 | Parent company or controlled by parent co./Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_IP:x28 | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 39.7 | Parent company or controlled by parent co./Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_IP:x28 | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 39.8 | Parent company or controlled by parent co./depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_IP:x28 | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 39.9 | Parent company or controlled by parent co./Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_IP:x28 | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 39.10 | Parent company or controlled by parent co./Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_IP:x28 | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 39.11 | Parent company or controlled by parent co./Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_IP:x28 | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 39.12 | Parent company or controlled by parent co./Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_IP:x28 | boi_MC:x30 | N/A | N/A | boi_RP:x24 | N/A | N/A | N/A |
| 40.1 | impaired bonds from which interest income is accrued/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | boi_MC:x962 | N/A | boi_RP:x24 | N/A | boi_ST:x3 | N/A |
| 40.2 | impaired bonds from which interest income is accrued/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | boi_MC:x962 | N/A | boi_RP:x24 | N/A | boi_ST:x3 | N/A |
| 40.3 | impaired bonds from which interest income is accrued/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | boi_MC:x962 | N/A | boi_RP:x24 | N/A | boi_ST:x3 | N/A |
| 40.4 | impaired bonds from which interest income is accrued/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | boi_MC:x962 | N/A | boi_RP:x24 | N/A | boi_ST:x3 | N/A |
| 40.5 | impaired bonds from which interest income is accrued/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | boi_MC:x962 | N/A | boi_RP:x24 | N/A | boi_ST:x3 | N/A |
| 40.6 | impaired bonds from which interest income is accrued/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | boi_MC:x962 | N/A | boi_RP:x24 | N/A | boi_ST:x3 | N/A |
| 40.7 | impaired bonds from which interest income is accrued/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | boi_MC:x962 | N/A | boi_RP:x24 | N/A | boi_ST:x3 | N/A |
| 40.8 | impaired bonds from which interest income is accrued/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | boi_MC:x962 | N/A | boi_RP:x24 | N/A | boi_ST:x3 | N/A |
| 40.9 | impaired bonds from which interest income is accrued/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | boi_MC:x962 | N/A | boi_RP:x24 | N/A | boi_ST:x3 | N/A |
| 40.10 | impaired bonds from which interest income is accrued/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | boi_MC:x962 | N/A | boi_RP:x24 | N/A | boi_ST:x3 | N/A |
| 40.11 | impaired bonds from which interest income is accrued/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | boi_MC:x962 | N/A | boi_RP:x24 | N/A | boi_ST:x3 | N/A |
| 40.12 | impaired bonds from which interest income is accrued/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | boi_MC:x962 | N/A | boi_RP:x24 | N/A | boi_ST:x3 | N/A |
| 41.1 | impaired bonds from which interest income is not accrued/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | boi_MC:x914 | N/A | boi_RP:x24 | N/A | boi_ST:x3 | N/A |
| 41.2 | impaired bonds from which interest income is not accrued/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | boi_MC:x914 | N/A | boi_RP:x24 | N/A | boi_ST:x3 | N/A |
| 41.3 | impaired bonds from which interest income is not accrued/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | boi_MC:x914 | N/A | boi_RP:x24 | N/A | boi_ST:x3 | N/A |
| 41.4 | impaired bonds from which interest income is not accrued/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | boi_MC:x914 | N/A | boi_RP:x24 | N/A | boi_ST:x3 | N/A |
| 41.5 | impaired bonds from which interest income is not accrued/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | boi_MC:x914 | N/A | boi_RP:x24 | N/A | boi_ST:x3 | N/A |
| 41.6 | impaired bonds from which interest income is not accrued/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | boi_MC:x914 | N/A | boi_RP:x24 | N/A | boi_ST:x3 | N/A |
| 41.7 | impaired bonds from which interest income is not accrued/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | boi_MC:x914 | N/A | boi_RP:x24 | N/A | boi_ST:x3 | N/A |
| 41.8 | impaired bonds from which interest income is not accrued/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | boi_MC:x914 | N/A | boi_RP:x24 | N/A | boi_ST:x3 | N/A |
| 41.9 | impaired bonds from which interest income is not accrued/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | boi_MC:x914 | N/A | boi_RP:x24 | N/A | boi_ST:x3 | N/A |
| 41.10 | impaired bonds from which interest income is not accrued/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | boi_MC:x914 | N/A | boi_RP:x24 | N/A | boi_ST:x3 | N/A |
| 41.11 | impaired bonds from which interest income is not accrued/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | boi_MC:x914 | N/A | boi_RP:x24 | N/A | boi_ST:x3 | N/A |
| 41.12 | impaired bonds from which interest income is not accrued/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | boi_MC:x914 | N/A | boi_RP:x24 | N/A | boi_ST:x3 | N/A |
| 42.1 | non-impaired bonds from which interest income is accrued,/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | boi_ST:x4 | boi_TI:x2 |
| 42.2 | non-impaired bonds from which interest income is accrued,/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | boi_ST:x4 | boi_TI:x2 |
| 42.3 | non-impaired bonds from which interest income is accrued,/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | boi_ST:x4 | boi_TI:x2 |
| 42.4 | non-impaired bonds from which interest income is accrued,/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | boi_ST:x4 | boi_TI:x2 |
| 42.5 | non-impaired bonds from which interest income is accrued,/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | boi_ST:x4 | boi_TI:x2 |
| 42.6 | non-impaired bonds from which interest income is accrued,/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | boi_ST:x4 | boi_TI:x2 |
| 42.7 | non-impaired bonds from which interest income is accrued,/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | boi_ST:x4 | boi_TI:x2 |
| 42.8 | non-impaired bonds from which interest income is accrued,/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | boi_ST:x4 | boi_TI:x2 |
| 42.9 | non-impaired bonds from which interest income is accrued,/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | boi_ST:x4 | boi_TI:x2 |
| 42.10 | non-impaired bonds from which interest income is accrued,/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | boi_ST:x4 | boi_TI:x2 |
| 42.11 | non-impaired bonds from which interest income is accrued,/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | boi_ST:x4 | boi_TI:x2 |
| 42.12 | non-impaired bonds from which interest income is accrued,/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | boi_ST:x4 | boi_TI:x2 |
| 43.1 | non-impaired bonds from which interest income is accrued,/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | boi_ST:x18 | boi_TI:x1 |
| 43.2 | non-impaired bonds from which interest income is accrued,/Depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | boi_ST:x18 | boi_TI:x1 |
| 43.3 | non-impaired bonds from which interest income is accrued,/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | boi_ST:x18 | boi_TI:x1 |
| 43.4 | non-impaired bonds from which interest income is accrued,/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | boi_ST:x18 | boi_TI:x1 |
| 43.5 | non-impaired bonds from which interest income is accrued,/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | boi_ST:x18 | boi_TI:x1 |
| 43.6 | non-impaired bonds from which interest income is accrued,/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | boi_ST:x18 | boi_TI:x1 |
| 43.7 | non-impaired bonds from which interest income is accrued,/Balance-sheet value | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | boi_ST:x18 | boi_TI:x1 |
| 43.8 | non-impaired bonds from which interest income is accrued,/depriciated cost (in shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | boi_ST:x18 | boi_TI:x1 |
| 43.9 | non-impaired bonds from which interest income is accrued,/Profit not yet realized from adjustment to fair value | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | boi_ST:x18 | boi_TI:x1 |
| 43.10 | non-impaired bonds from which interest income is accrued,/Losses not yet realized from adjustment to fair value | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | boi_ST:x18 | boi_TI:x1 |
| 43.11 | non-impaired bonds from which interest income is accrued,/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | boi_ST:x18 | boi_TI:x1 |
| 43.12 | non-impaired bonds from which interest income is accrued,/Other profit or loss, hedging of expected transactions | boi_met:mi4 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_MC:x15 | N/A | N/A | boi_RP:x24 | N/A | boi_ST:x18 | boi_TI:x1 |