| r0.1 | label_boi_a2/Amount of of exposure at the beginning of the period | boi_met:mi540 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_FN:x1 | boi_GA:x39 | N/A | boi_GA:x2 | boi_MC:x1 | N/A | boi_RP:x24 | boi_RP:x22 |
| r0.2 | label_boi_a2/Net changes in short term exposure | boi_met:md552 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_FN:x1 | boi_GA:x39 | N/A | boi_GA:x2 | boi_MC:x1 | boi_MU:x1 | boi_RP:x24 | N/A |
| r0.3 | label_boi_a2/Additional exposures | boi_met:md551 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_FN:x1 | boi_GA:x39 | N/A | boi_GA:x2 | boi_MC:x1 | boi_MU:x1 | boi_RP:x24 | N/A |
| r0.4 | label_boi_a2/Accrued interest income | boi_met:md550 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_FN:x1 | boi_GA:x39 | N/A | boi_GA:x2 | boi_MC:x1 | boi_MU:x1 | boi_RP:x24 | N/A |
| r0.5 | label_boi_a2/Amounts collected | boi_met:md549 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_FN:x1 | boi_GA:x39 | N/A | boi_GA:x2 | boi_MC:x1 | boi_MU:x1 | boi_RP:x24 | N/A |
| r0.6 | label_boi_a2/Others changes | boi_met:md548 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_FN:x1 | boi_GA:x39 | N/A | boi_GA:x2 | boi_MC:x1 | boi_MU:x1 | boi_RP:x24 | N/A |
| r0.7 | label_boi_a2/Amount of of exposure at the end of the period | boi_met:mi540 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_FN:x1 | boi_GA:x39 | N/A | boi_GA:x2 | boi_MC:x1 | N/A | boi_RP:x24 | N/A |
| 20.1 | Other countries/Amount of of exposure at the beginning of the period | boi_met:mi540 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_FN:x1 | boi_GA:x39 | boi_GA:x26 | boi_GA:x2 | boi_MC:x1 | N/A | boi_RP:x24 | boi_RP:x22 |
| 20.2 | Other countries/Net changes in short term exposure | boi_met:md552 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_FN:x1 | boi_GA:x39 | boi_GA:x26 | boi_GA:x2 | boi_MC:x1 | boi_MU:x1 | boi_RP:x24 | N/A |
| 20.3 | Other countries/Additional exposures | boi_met:md551 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_FN:x1 | boi_GA:x39 | boi_GA:x26 | boi_GA:x2 | boi_MC:x1 | boi_MU:x1 | boi_RP:x24 | N/A |
| 20.4 | Other countries/Accrued interest income | boi_met:md550 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_FN:x1 | boi_GA:x39 | boi_GA:x26 | boi_GA:x2 | boi_MC:x1 | boi_MU:x1 | boi_RP:x24 | N/A |
| 20.5 | Other countries/Amounts collected | boi_met:md549 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_FN:x1 | boi_GA:x39 | boi_GA:x26 | boi_GA:x2 | boi_MC:x1 | boi_MU:x1 | boi_RP:x24 | N/A |
| 20.6 | Other countries/Others changes | boi_met:md548 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_FN:x1 | boi_GA:x39 | boi_GA:x26 | boi_GA:x2 | boi_MC:x1 | boi_MU:x1 | boi_RP:x24 | N/A |
| 20.7 | Other countries/Amount of of exposure at the end of the period | boi_met:mi540 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_FN:x1 | boi_GA:x39 | boi_GA:x26 | boi_GA:x2 | boi_MC:x1 | N/A | boi_RP:x24 | N/A |
| 21.1 | Total/Amount of of exposure at the beginning of the period | boi_met:mi540 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_FN:x1 | boi_GA:x39 | N/A | boi_GA:x2 | boi_MC:x1 | N/A | boi_RP:x24 | boi_RP:x22 |
| 21.2 | Total/Net changes in short term exposure | boi_met:md552 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_FN:x1 | boi_GA:x39 | N/A | boi_GA:x2 | boi_MC:x1 | boi_MU:x1 | boi_RP:x24 | N/A |
| 21.3 | Total/Additional exposures | boi_met:md551 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_FN:x1 | boi_GA:x39 | N/A | boi_GA:x2 | boi_MC:x1 | boi_MU:x1 | boi_RP:x24 | N/A |
| 21.4 | Total/Accrued interest income | boi_met:md550 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_FN:x1 | boi_GA:x39 | N/A | boi_GA:x2 | boi_MC:x1 | boi_MU:x1 | boi_RP:x24 | N/A |
| 21.5 | Total/Amounts collected | boi_met:md549 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_FN:x1 | boi_GA:x39 | N/A | boi_GA:x2 | boi_MC:x1 | boi_MU:x1 | boi_RP:x24 | N/A |
| 21.6 | Total/Others changes | boi_met:md548 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_FN:x1 | boi_GA:x39 | N/A | boi_GA:x2 | boi_MC:x1 | boi_MU:x1 | boi_RP:x24 | N/A |
| 21.7 | Total/Amount of of exposure at the end of the period | boi_met:mi540 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_FN:x1 | boi_GA:x39 | N/A | boi_GA:x2 | boi_MC:x1 | N/A | boi_RP:x24 | N/A |