| r0.1 | label_boi_a2/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_RP:x24 |
| r0.2 | label_boi_a2/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_RP:x24 |
| r0.3 | label_boi_a2/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_RP:x24 |
| r0.4 | label_boi_a2/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_RP:x24 |
| r1.1 | Securities available for sale/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x1 | boi_RP:x24 |
| r1.2 | Securities available for sale/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x1 | boi_RP:x24 |
| r1.3 | Securities available for sale/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x1 | boi_RP:x24 |
| r1.4 | Securities available for sale/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x1 | boi_RP:x24 |
| r2.1 | Mortgage backed securities (MBS)/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x1 | boi_RP:x24 |
| r2.2 | 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 |
| r2.3 | 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 |
| r2.4 | 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 |
| r3.1 | Pass through securities:/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x1 | boi_RP:x24 |
| r3.2 | Pass through securities:/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x1 | boi_RP:x24 |
| r3.3 | Pass through securities:/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x1 | boi_RP:x24 |
| r3.4 | 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 | 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 | 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 | 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 | 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 |
| r8.1 | Other MBS securities (incl. CMO, REMIC ו- STRIPPED MBS):/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x1 | boi_RP:x24 |
| r8.2 | 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 |
| r8.3 | 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 |
| r8.4 | 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 | 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 | 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 | 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 | 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 | 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 |
| r14.1 | Asset backed securities (ABS)/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x1 | boi_RP:x24 |
| r14.2 | Asset backed securities (ABS)/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x1 | boi_RP:x24 |
| r14.3 | Asset backed securities (ABS)/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x1 | boi_RP:x24 |
| r14.4 | Asset backed securities (ABS)/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x1 | boi_RP:x24 |
| 10.1 | Credit card receivables/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x310 | boi_PL:x1 | boi_RP:x24 |
| 10.2 | Credit card receivables/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x310 | boi_PL:x1 | boi_RP:x24 |
| 10.3 | Credit card receivables/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x310 | boi_PL:x1 | boi_RP:x24 |
| 10.4 | Credit card receivables/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 | 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 | 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 | 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 | 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 | 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 | 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 | 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 |
| r23.1 | Bonds held to maturity/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x5 | boi_RP:x24 |
| r23.2 | Bonds held to maturity/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x5 | boi_RP:x24 |
| r23.3 | Bonds held to maturity/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x5 | boi_RP:x24 |
| r23.4 | Bonds held to maturity/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x5 | boi_RP:x24 |
| r24.1 | Mortgage backed securities (MBS)/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x5 | boi_RP:x24 |
| r24.2 | Mortgage backed securities (MBS)/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x5 | boi_RP:x24 |
| r24.3 | Mortgage backed securities (MBS)/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x5 | boi_RP:x24 |
| r24.4 | Mortgage backed securities (MBS)/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x5 | boi_RP:x24 |
| r25.1 | Pass through securities:/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x5 | boi_RP:x24 |
| r25.2 | Pass through securities:/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x5 | boi_RP:x24 |
| r25.3 | Pass through securities:/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x5 | boi_RP:x24 |
| r25.4 | Pass through securities:/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x5 | boi_RP:x24 |
| 18.1 | GNMA guaranteed securities/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x317 | boi_PL:x5 | boi_RP:x24 |
| 18.2 | GNMA guaranteed securities/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x317 | boi_PL:x5 | boi_RP:x24 |
| 18.3 | GNMA guaranteed securities/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x317 | boi_PL:x5 | boi_RP:x24 |
| 18.4 | GNMA guaranteed securities/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x317 | boi_PL:x5 | boi_RP:x24 |
| 19.1 | Securities issued by FHLMC and FNMA/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x318 | boi_PL:x5 | boi_RP:x24 |
| 19.2 | Securities issued by FHLMC and FNMA/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x318 | boi_PL:x5 | boi_RP:x24 |
| 19.3 | Securities issued by FHLMC and FNMA/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x318 | boi_PL:x5 | boi_RP:x24 |
| 19.4 | 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:x5 | boi_RP:x24 |
| 20.1 | Other securities/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x319 | boi_PL:x5 | boi_RP:x24 |
| 20.2 | Other securities/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x319 | boi_PL:x5 | boi_RP:x24 |
| 20.3 | Other securities/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x319 | boi_PL:x5 | boi_RP:x24 |
| 20.4 | Other securities/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x319 | boi_PL:x5 | boi_RP:x24 |
| r29.1 | Other MBS securities (incl. CMO, REMIC ו- STRIPPED MBS):/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x5 | boi_RP:x24 |
| r29.2 | 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:x5 | boi_RP:x24 |
| r29.3 | 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:x5 | boi_RP:x24 |
| r29.4 | 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:x5 | boi_RP:x24 |
| 21.1 | Securities issued or guaranteed by FHLMC, GNMA or FHMA/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x321 | boi_PL:x5 | boi_RP:x24 |
| 21.2 | 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:x5 | boi_RP:x24 |
| 21.3 | 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:x5 | boi_RP:x24 |
| 21.4 | 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:x5 | boi_RP:x24 |
| 22.1 | Securities secured by FHLMC, GNMA or FHMA/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x322 | boi_PL:x5 | boi_RP:x24 |
| 22.2 | 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:x5 | boi_RP:x24 |
| 22.3 | 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:x5 | boi_RP:x24 |
| 22.4 | 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:x5 | boi_RP:x24 |
| 23.1 | Other MBS securities/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x323 | boi_PL:x5 | boi_RP:x24 |
| 23.2 | Other MBS securities/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x323 | boi_PL:x5 | boi_RP:x24 |
| 23.3 | Other MBS securities/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x323 | boi_PL:x5 | boi_RP:x24 |
| 23.4 | Other MBS securities/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x323 | boi_PL:x5 | boi_RP:x24 |
| 24.1 | Total MBS securities/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x120 | boi_PL:x5 | boi_RP:x24 |
| 24.2 | Total MBS securities/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x120 | boi_PL:x5 | boi_RP:x24 |
| 24.3 | Total MBS securities/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x120 | boi_PL:x5 | boi_RP:x24 |
| 24.4 | Total MBS securities/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x120 | boi_PL:x5 | boi_RP:x24 |
| r34.1 | Asset backed securities (ABS)/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x5 | boi_RP:x24 |
| r34.2 | Asset backed securities (ABS)/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x5 | boi_RP:x24 |
| r34.3 | Asset backed securities (ABS)/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x5 | boi_RP:x24 |
| r34.4 | Asset backed securities (ABS)/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x5 | boi_RP:x24 |
| 25.1 | Credit card receivables/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x310 | boi_PL:x5 | boi_RP:x24 |
| 25.2 | Credit card receivables/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x310 | boi_PL:x5 | boi_RP:x24 |
| 25.3 | Credit card receivables/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x310 | boi_PL:x5 | boi_RP:x24 |
| 25.4 | Credit card receivables/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x310 | boi_PL:x5 | boi_RP:x24 |
| 26.1 | Credit lines for any purpose secured by residential apartments/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x311 | boi_PL:x5 | boi_RP:x24 |
| 26.2 | 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:x5 | boi_RP:x24 |
| 26.3 | 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:x5 | boi_RP:x24 |
| 26.4 | 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:x5 | boi_RP:x24 |
| 27.1 | Credit for purchase of automobile/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x312 | boi_PL:x5 | boi_RP:x24 |
| 27.2 | Credit for purchase of automobile/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x312 | boi_PL:x5 | boi_RP:x24 |
| 27.3 | Credit for purchase of automobile/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x312 | boi_PL:x5 | boi_RP:x24 |
| 27.4 | Credit for purchase of automobile/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x312 | boi_PL:x5 | boi_RP:x24 |
| 28.1 | Other credit for private individuals/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x313 | boi_PL:x5 | boi_RP:x24 |
| 28.2 | Other credit for private individuals/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x313 | boi_PL:x5 | boi_RP:x24 |
| 28.3 | Other credit for private individuals/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x313 | boi_PL:x5 | boi_RP:x24 |
| 28.4 | Other credit for private individuals/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x313 | boi_PL:x5 | boi_RP:x24 |
| 29.1 | Credit not for private individuals/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x314 | boi_PL:x5 | boi_RP:x24 |
| 29.2 | Credit not for private individuals/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x314 | boi_PL:x5 | boi_RP:x24 |
| 29.3 | Credit not for private individuals/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x314 | boi_PL:x5 | boi_RP:x24 |
| 29.4 | Credit not for private individuals/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x314 | boi_PL:x5 | boi_RP:x24 |
| 30.1 | Other securities/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x315 | boi_PL:x5 | boi_RP:x24 |
| 30.2 | Other securities/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x315 | boi_PL:x5 | boi_RP:x24 |
| 30.3 | Other securities/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x315 | boi_PL:x5 | boi_RP:x24 |
| 30.4 | Other securities/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x315 | boi_PL:x5 | boi_RP:x24 |
| 31.1 | Total ABS securities/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x119 | boi_PL:x5 | boi_RP:x24 |
| 31.2 | Total ABS securities/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x119 | boi_PL:x5 | boi_RP:x24 |
| 31.3 | Total ABS securities/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x119 | boi_PL:x5 | boi_RP:x24 |
| 31.4 | Total ABS securities/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x119 | boi_PL:x5 | boi_RP:x24 |
| 32.1 | Total mortgage-backed and asset-backed bonds held to maturity/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x5 | boi_PL:x5 | boi_RP:x24 |
| 32.2 | Total mortgage-backed and asset-backed bonds held to maturity/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x5 | boi_PL:x5 | boi_RP:x24 |
| 32.3 | Total mortgage-backed and asset-backed bonds held to maturity/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x5 | boi_PL:x5 | boi_RP:x24 |
| 32.4 | Total mortgage-backed and asset-backed bonds held to maturity/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x5 | boi_PL:x5 | boi_RP:x24 |
| r43.1 | Securities held for trading/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x2 | boi_RP:x24 |
| r43.2 | Securities held for trading/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x2 | boi_RP:x24 |
| r43.3 | Securities held for trading/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x2 | boi_RP:x24 |
| r43.4 | Securities held for trading/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x2 | boi_RP:x24 |
| r44.1 | Mortgage backed securities (MBS)/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x2 | boi_RP:x24 |
| r44.2 | Mortgage backed securities (MBS)/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x2 | boi_RP:x24 |
| r44.3 | Mortgage backed securities (MBS)/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x2 | boi_RP:x24 |
| r44.4 | Mortgage backed securities (MBS)/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x2 | boi_RP:x24 |
| r45.1 | Pass through securities:/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x2 | boi_RP:x24 |
| r45.2 | Pass through securities:/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x2 | boi_RP:x24 |
| r45.3 | Pass through securities:/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x2 | boi_RP:x24 |
| r45.4 | Pass through securities:/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x2 | boi_RP:x24 |
| 33.1 | GNMA guaranteed securities/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x317 | boi_PL:x2 | boi_RP:x24 |
| 33.2 | GNMA guaranteed securities/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x317 | boi_PL:x2 | boi_RP:x24 |
| 33.3 | GNMA guaranteed securities/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x317 | boi_PL:x2 | boi_RP:x24 |
| 33.4 | GNMA guaranteed securities/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x317 | boi_PL:x2 | boi_RP:x24 |
| 34.1 | Securities issued by FHLMC and FNMA/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x318 | boi_PL:x2 | boi_RP:x24 |
| 34.2 | Securities issued by FHLMC and FNMA/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x318 | boi_PL:x2 | boi_RP:x24 |
| 34.3 | Securities issued by FHLMC and FNMA/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x318 | boi_PL:x2 | boi_RP:x24 |
| 34.4 | 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:x2 | boi_RP:x24 |
| 35.1 | Other securities/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x319 | boi_PL:x2 | boi_RP:x24 |
| 35.2 | Other securities/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x319 | boi_PL:x2 | boi_RP:x24 |
| 35.3 | Other securities/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x319 | boi_PL:x2 | boi_RP:x24 |
| 35.4 | Other securities/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x319 | boi_PL:x2 | boi_RP:x24 |
| 36.1 | Total pass through MBS securities/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x316 | boi_PL:x2 | boi_RP:x24 |
| 36.2 | Total pass through MBS securities/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x316 | boi_PL:x2 | boi_RP:x24 |
| 36.3 | Total pass through MBS securities/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x316 | boi_PL:x2 | boi_RP:x24 |
| 36.4 | Total pass through MBS securities/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x316 | boi_PL:x2 | boi_RP:x24 |
| r50.1 | Other MBS securities (incl. CMO, REMIC ו- STRIPPED MBS):/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x2 | boi_RP:x24 |
| r50.2 | 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:x2 | boi_RP:x24 |
| r50.3 | 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:x2 | boi_RP:x24 |
| r50.4 | 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:x2 | boi_RP:x24 |
| 37.1 | Securities issued or guaranteed by FHLMC, GNMA or FHMA/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x321 | boi_PL:x2 | boi_RP:x24 |
| 37.2 | 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:x2 | boi_RP:x24 |
| 37.3 | 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:x2 | boi_RP:x24 |
| 37.4 | 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:x2 | boi_RP:x24 |
| 38.1 | Securities secured by FHLMC, GNMA or FHMA/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x322 | boi_PL:x2 | boi_RP:x24 |
| 38.2 | 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:x2 | boi_RP:x24 |
| 38.3 | 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:x2 | boi_RP:x24 |
| 38.4 | 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:x2 | boi_RP:x24 |
| 39.1 | Other MBS securities/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x323 | boi_PL:x2 | boi_RP:x24 |
| 39.2 | Other MBS securities/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x323 | boi_PL:x2 | boi_RP:x24 |
| 39.3 | Other MBS securities/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x323 | boi_PL:x2 | boi_RP:x24 |
| 39.4 | Other MBS securities/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x323 | boi_PL:x2 | boi_RP:x24 |
| 40.1 | Total other MBS securities/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x320 | boi_PL:x2 | boi_RP:x24 |
| 40.2 | Total other MBS securities/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x320 | boi_PL:x2 | boi_RP:x24 |
| 40.3 | Total other MBS securities/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x320 | boi_PL:x2 | boi_RP:x24 |
| 40.4 | Total other MBS securities/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x320 | boi_PL:x2 | boi_RP:x24 |
| 41.1 | Total MBS securities/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x120 | boi_PL:x2 | boi_RP:x24 |
| 41.2 | Total MBS securities/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x120 | boi_PL:x2 | boi_RP:x24 |
| 41.3 | Total MBS securities/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x120 | boi_PL:x2 | boi_RP:x24 |
| 41.4 | Total MBS securities/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x120 | boi_PL:x2 | boi_RP:x24 |
| r56.1 | Asset backed securities (ABS)/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x2 | boi_RP:x24 |
| r56.2 | Asset backed securities (ABS)/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x2 | boi_RP:x24 |
| r56.3 | Asset backed securities (ABS)/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x2 | boi_RP:x24 |
| r56.4 | Asset backed securities (ABS)/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_PL:x2 | boi_RP:x24 |
| 42.1 | Credit card receivables/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x310 | boi_PL:x2 | boi_RP:x24 |
| 42.2 | Credit card receivables/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x310 | boi_PL:x2 | boi_RP:x24 |
| 42.3 | Credit card receivables/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x310 | boi_PL:x2 | boi_RP:x24 |
| 42.4 | Credit card receivables/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x310 | boi_PL:x2 | boi_RP:x24 |
| 43.1 | Credit lines for any purpose secured by residential apartments/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x311 | boi_PL:x2 | boi_RP:x24 |
| 43.2 | 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:x2 | boi_RP:x24 |
| 43.3 | 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:x2 | boi_RP:x24 |
| 43.4 | 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:x2 | boi_RP:x24 |
| 44.1 | Credit for purchase of automobile/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x312 | boi_PL:x2 | boi_RP:x24 |
| 44.2 | Credit for purchase of automobile/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x312 | boi_PL:x2 | boi_RP:x24 |
| 44.3 | Credit for purchase of automobile/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x312 | boi_PL:x2 | boi_RP:x24 |
| 44.4 | Credit for purchase of automobile/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x312 | boi_PL:x2 | boi_RP:x24 |
| 45.1 | Other credit for private individuals/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x313 | boi_PL:x2 | boi_RP:x24 |
| 45.2 | Other credit for private individuals/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x313 | boi_PL:x2 | boi_RP:x24 |
| 45.3 | Other credit for private individuals/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x313 | boi_PL:x2 | boi_RP:x24 |
| 45.4 | Other credit for private individuals/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x313 | boi_PL:x2 | boi_RP:x24 |
| 46.1 | Credit not for private individuals/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x314 | boi_PL:x2 | boi_RP:x24 |
| 46.2 | Credit not for private individuals/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x314 | boi_PL:x2 | boi_RP:x24 |
| 46.3 | Credit not for private individuals/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x314 | boi_PL:x2 | boi_RP:x24 |
| 46.4 | Credit not for private individuals/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x314 | boi_PL:x2 | boi_RP:x24 |
| 47.1 | Other securities/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x315 | boi_PL:x2 | boi_RP:x24 |
| 47.2 | Other securities/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x315 | boi_PL:x2 | boi_RP:x24 |
| 47.3 | Other securities/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x315 | boi_PL:x2 | boi_RP:x24 |
| 47.4 | Other securities/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x315 | boi_PL:x2 | boi_RP:x24 |
| 48.1 | Total ABS securities/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x119 | boi_PL:x2 | boi_RP:x24 |
| 48.2 | Total ABS securities/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x119 | boi_PL:x2 | boi_RP:x24 |
| 48.3 | Total ABS securities/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x119 | boi_PL:x2 | boi_RP:x24 |
| 48.4 | Total ABS securities/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x119 | boi_PL:x2 | boi_RP:x24 |
| 49.1 | Total MBS and ABS for trading/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x5 | boi_PL:x2 | boi_RP:x24 |
| 49.2 | Total MBS and ABS for trading/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x5 | boi_PL:x2 | boi_RP:x24 |
| 49.3 | Total MBS and ABS for trading/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x5 | boi_PL:x2 | boi_RP:x24 |
| 49.4 | Total MBS and ABS for trading/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x5 | boi_PL:x2 | boi_RP:x24 |
| 50.1 | Total MBS and ABS/Amortized cost | boi_met:mi8 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x5 | N/A | boi_RP:x24 |
| 50.2 | Total MBS and ABS/Profits | boi_met:mi7 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x5 | N/A | boi_RP:x24 |
| 50.3 | Total MBS and ABS/Losses | boi_met:mi6 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x5 | N/A | boi_RP:x24 |
| 50.4 | Total MBS and ABS/Fair value | boi_met:mi5 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x5 | N/A | boi_RP:x24 |