| r0.1 | label_boi_a2/Amortized cost (with shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x1 | boi_RP:x24 |
| r0.2 | label_boi_a2/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x1 | boi_RP:x24 |
| r0.3 | label_boi_a2/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x1 | boi_RP:x24 |
| r0.4 | label_boi_a2/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x1 | boi_RP:x24 |
| r1.1 | Mortgage backed securities (MBS)/Amortized cost (with shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x1 | boi_RP:x24 |
| r1.2 | Mortgage backed securities (MBS)/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x1 | boi_RP:x24 |
| r1.3 | Mortgage backed securities (MBS)/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x1 | boi_RP:x24 |
| r1.4 | Mortgage backed securities (MBS)/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x1 | boi_RP:x24 |
| r2.1 | Pass through securities:/Amortized cost (with shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x1 | boi_RP:x24 |
| r2.2 | Pass through securities:/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x1 | boi_RP:x24 |
| r2.3 | Pass through securities:/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x1 | boi_RP:x24 |
| r2.4 | Pass through securities:/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x1 | boi_RP:x24 |
| 1.1 | GNMA guaranteed securities/Amortized cost (with shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x317 | boi_PL:x1 | boi_RP:x24 |
| 1.2 | GNMA guaranteed securities/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x317 | boi_PL:x1 | boi_RP:x24 |
| 1.3 | GNMA guaranteed securities/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x317 | boi_PL:x1 | boi_RP:x24 |
| 1.4 | GNMA guaranteed securities/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x317 | boi_PL:x1 | boi_RP:x24 |
| 2.1 | Securities issued by FHLMC and FNMA/Amortized cost (with shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x318 | boi_PL:x1 | boi_RP:x24 |
| 2.2 | Securities issued by FHLMC and FNMA/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x318 | boi_PL:x1 | boi_RP:x24 |
| 2.3 | Securities issued by FHLMC and FNMA/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x318 | boi_PL:x1 | boi_RP:x24 |
| 2.4 | Securities issued by FHLMC and FNMA/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x318 | boi_PL:x1 | boi_RP:x24 |
| 3.1 | Other securities/Amortized cost (with shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x319 | boi_PL:x1 | boi_RP:x24 |
| 3.2 | Other securities/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x319 | boi_PL:x1 | boi_RP:x24 |
| 3.3 | Other securities/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x319 | boi_PL:x1 | boi_RP:x24 |
| 3.4 | Other securities/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x319 | boi_PL:x1 | boi_RP:x24 |
| 4.1 | Total pass through MBS securities/Amortized cost (with shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x316 | boi_PL:x1 | boi_RP:x24 |
| 4.2 | Total pass through MBS securities/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x316 | boi_PL:x1 | boi_RP:x24 |
| 4.3 | Total pass through MBS securities/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x316 | boi_PL:x1 | boi_RP:x24 |
| 4.4 | Total pass through MBS securities/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x316 | boi_PL:x1 | boi_RP:x24 |
| r7.1 | Other MBS securities (incl. CMO, REMIC ו- STRIPPED MBS):/Amortized cost (with shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x1 | boi_RP:x24 |
| r7.2 | Other MBS securities (incl. CMO, REMIC ו- STRIPPED MBS):/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x1 | boi_RP:x24 |
| r7.3 | Other MBS securities (incl. CMO, REMIC ו- STRIPPED MBS):/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x1 | boi_RP:x24 |
| r7.4 | Other MBS securities (incl. CMO, REMIC ו- STRIPPED MBS):/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x1 | boi_RP:x24 |
| 5.1 | Securities issued or guaranteed by FHLMC, GNMA or FHMA/Amortized cost (with shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x321 | boi_PL:x1 | boi_RP:x24 |
| 5.2 | Securities issued or guaranteed by FHLMC, GNMA or FHMA/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x321 | boi_PL:x1 | boi_RP:x24 |
| 5.3 | Securities issued or guaranteed by FHLMC, GNMA or FHMA/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x321 | boi_PL:x1 | boi_RP:x24 |
| 5.4 | Securities issued or guaranteed by FHLMC, GNMA or FHMA/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x321 | boi_PL:x1 | boi_RP:x24 |
| 6.1 | Securities secured by FHLMC, GNMA or FHMA/Amortized cost (with shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x322 | boi_PL:x1 | boi_RP:x24 |
| 6.2 | Securities secured by FHLMC, GNMA or FHMA/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x322 | boi_PL:x1 | boi_RP:x24 |
| 6.3 | Securities secured by FHLMC, GNMA or FHMA/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x322 | boi_PL:x1 | boi_RP:x24 |
| 6.4 | Securities secured by FHLMC, GNMA or FHMA/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x322 | boi_PL:x1 | boi_RP:x24 |
| 7.1 | Other MBS securities/Amortized cost (with shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x323 | boi_PL:x1 | boi_RP:x24 |
| 7.2 | Other MBS securities/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x323 | boi_PL:x1 | boi_RP:x24 |
| 7.3 | Other MBS securities/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x323 | boi_PL:x1 | boi_RP:x24 |
| 7.4 | Other MBS securities/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x323 | boi_PL:x1 | boi_RP:x24 |
| 8.1 | Total other MBS securities/Amortized cost (with shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x320 | boi_PL:x1 | boi_RP:x24 |
| 8.2 | Total other MBS securities/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x320 | boi_PL:x1 | boi_RP:x24 |
| 8.3 | Total other MBS securities/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x320 | boi_PL:x1 | boi_RP:x24 |
| 8.4 | Total other MBS securities/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x320 | boi_PL:x1 | boi_RP:x24 |
| 9.1 | Total MBS securities/Amortized cost (with shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x120 | boi_PL:x1 | boi_RP:x24 |
| 9.2 | Total MBS securities/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x120 | boi_PL:x1 | boi_RP:x24 |
| 9.3 | Total MBS securities/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x120 | boi_PL:x1 | boi_RP:x24 |
| 9.4 | Total MBS securities/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x120 | boi_PL:x1 | boi_RP:x24 |
| r13.1 | Asset backed securities/Amortized cost (with shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x1 | boi_RP:x24 |
| r13.2 | Asset backed securities/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x1 | boi_RP:x24 |
| r13.3 | Asset backed securities/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x1 | boi_RP:x24 |
| r13.4 | Asset backed securities/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x1 | boi_RP:x24 |
| 10.1 | Receivables in respect of credit cards/Amortized cost (with shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x310 | boi_PL:x1 | boi_RP:x24 |
| 10.2 | Receivables in respect of credit cards/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x310 | boi_PL:x1 | boi_RP:x24 |
| 10.3 | Receivables in respect of credit cards/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x310 | boi_PL:x1 | boi_RP:x24 |
| 10.4 | Receivables in respect of credit cards/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x310 | boi_PL:x1 | boi_RP:x24 |
| 11.1 | Credit lines for any purpose secured by residential apartments/Amortized cost (with shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x311 | boi_PL:x1 | boi_RP:x24 |
| 11.2 | Credit lines for any purpose secured by residential apartments/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x311 | boi_PL:x1 | boi_RP:x24 |
| 11.3 | Credit lines for any purpose secured by residential apartments/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x311 | boi_PL:x1 | boi_RP:x24 |
| 11.4 | Credit lines for any purpose secured by residential apartments/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x311 | boi_PL:x1 | boi_RP:x24 |
| 12.1 | Credit for purchase of automobile/Amortized cost (with shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x312 | boi_PL:x1 | boi_RP:x24 |
| 12.2 | Credit for purchase of automobile/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x312 | boi_PL:x1 | boi_RP:x24 |
| 12.3 | Credit for purchase of automobile/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x312 | boi_PL:x1 | boi_RP:x24 |
| 12.4 | Credit for purchase of automobile/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x312 | boi_PL:x1 | boi_RP:x24 |
| 13.1 | Other credit for private individuals/Amortized cost (with shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x313 | boi_PL:x1 | boi_RP:x24 |
| 13.2 | Other credit for private individuals/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x313 | boi_PL:x1 | boi_RP:x24 |
| 13.3 | Other credit for private individuals/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x313 | boi_PL:x1 | boi_RP:x24 |
| 13.4 | Other credit for private individuals/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x313 | boi_PL:x1 | boi_RP:x24 |
| 14.1 | Credit not for private individuals/Amortized cost (with shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x314 | boi_PL:x1 | boi_RP:x24 |
| 14.2 | Credit not for private individuals/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x314 | boi_PL:x1 | boi_RP:x24 |
| 14.3 | Credit not for private individuals/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x314 | boi_PL:x1 | boi_RP:x24 |
| 14.4 | Credit not for private individuals/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x314 | boi_PL:x1 | boi_RP:x24 |
| 15.1 | Other securities/Amortized cost (with shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x315 | boi_PL:x1 | boi_RP:x24 |
| 15.2 | Other securities/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x315 | boi_PL:x1 | boi_RP:x24 |
| 15.3 | Other securities/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x315 | boi_PL:x1 | boi_RP:x24 |
| 15.4 | Other securities/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x315 | boi_PL:x1 | boi_RP:x24 |
| 16.1 | Total ABS securities/Amortized cost (with shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x119 | boi_PL:x1 | boi_RP:x24 |
| 16.2 | Total ABS securities/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x119 | boi_PL:x1 | boi_RP:x24 |
| 16.3 | Total ABS securities/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x119 | boi_PL:x1 | boi_RP:x24 |
| 16.4 | Total ABS securities/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x119 | boi_PL:x1 | boi_RP:x24 |
| 17.1 | Total MBS and ABS available for sale/Amortized cost (with shares, cost) | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x5 | boi_PL:x1 | boi_RP:x24 |
| 17.2 | Total MBS and ABS available for sale/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x5 | boi_PL:x1 | boi_RP:x24 |
| 17.3 | Total MBS and ABS available for sale/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x5 | boi_PL:x1 | boi_RP:x24 |
| 17.4 | Total MBS and ABS available for sale/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x5 | boi_PL:x1 | boi_RP:x24 |