| r0.1 | label_boi_a2/On demand up to one month | boi_met:mi1205 | xbrli:monetaryItemType | instant | boi_CS:x2 | boi_FN:x1 | N/A | boi_TI:x14 |
| r0.2 | label_boi_a2/Over one month to three months | boi_met:mi1205 | xbrli:monetaryItemType | instant | boi_CS:x2 | boi_FN:x1 | N/A | boi_TI:x15 |
| r0.3 | label_boi_a2/Over three months to one year | boi_met:mi1205 | xbrli:monetaryItemType | instant | boi_CS:x2 | boi_FN:x1 | N/A | boi_TI:x16 |
| r0.4 | label_boi_a2/Over one year to three years | boi_met:mi1205 | xbrli:monetaryItemType | instant | boi_CS:x2 | boi_FN:x1 | N/A | boi_TI:x17 |
| r0.5 | label_boi_a2/Over three years to five years | boi_met:mi1205 | xbrli:monetaryItemType | instant | boi_CS:x2 | boi_FN:x1 | N/A | boi_TI:x18 |
| r0.6 | label_boi_a2/Over five years to ten years | boi_met:mi1205 | xbrli:monetaryItemType | instant | boi_CS:x2 | boi_FN:x1 | N/A | boi_TI:x20 |
| r0.7 | label_boi_a2/Over ten years to twenty years | boi_met:mi1205 | xbrli:monetaryItemType | instant | boi_CS:x2 | boi_FN:x1 | N/A | boi_TI:x21 |
| r0.8 | label_boi_a2/Over twenty years | boi_met:mi1205 | xbrli:monetaryItemType | instant | boi_CS:x2 | boi_FN:x1 | N/A | boi_TI:x22 |
| r0.9 | label_boi_a2/Without fixed maturity | boi_met:mi1205 | xbrli:monetaryItemType | instant | boi_CS:x2 | boi_FN:x1 | N/A | boi_TI:x23 |
| r0.10 | label_boi_a2/Total fair value | boi_met:mi1205 | xbrli:monetaryItemType | instant | boi_CS:x2 | boi_FN:x1 | boi_RP:x24 | N/A |
| r0.11 | label_boi_a2/Internal rate of return | boi_met:pi1208 | num:percentItemType | instant | boi_CS:x2 | boi_FN:x1 | boi_RP:x24 | N/A |
| r0.12 | label_boi_a2/Average duration | boi_met:ri1209 | xbrli:decimalItemType | instant | boi_CS:x2 | boi_FN:x1 | boi_RP:x24 | N/A |
| r1.1 | Effect on exposure to changes in interest the rates/On demand up to one month | boi_met:mi1205 | xbrli:monetaryItemType | instant | boi_CS:x2 | boi_FN:x1 | N/A | boi_TI:x14 |
| r1.2 | Effect on exposure to changes in interest the rates/Over one month to three months | boi_met:mi1205 | xbrli:monetaryItemType | instant | boi_CS:x2 | boi_FN:x1 | N/A | boi_TI:x15 |
| r1.3 | Effect on exposure to changes in interest the rates/Over three months to one year | boi_met:mi1205 | xbrli:monetaryItemType | instant | boi_CS:x2 | boi_FN:x1 | N/A | boi_TI:x16 |
| r1.4 | Effect on exposure to changes in interest the rates/Over one year to three years | boi_met:mi1205 | xbrli:monetaryItemType | instant | boi_CS:x2 | boi_FN:x1 | N/A | boi_TI:x17 |
| r1.5 | Effect on exposure to changes in interest the rates/Over three years to five years | boi_met:mi1205 | xbrli:monetaryItemType | instant | boi_CS:x2 | boi_FN:x1 | N/A | boi_TI:x18 |
| r1.6 | Effect on exposure to changes in interest the rates/Over five years to ten years | boi_met:mi1205 | xbrli:monetaryItemType | instant | boi_CS:x2 | boi_FN:x1 | N/A | boi_TI:x20 |
| r1.7 | Effect on exposure to changes in interest the rates/Over ten years to twenty years | boi_met:mi1205 | xbrli:monetaryItemType | instant | boi_CS:x2 | boi_FN:x1 | N/A | boi_TI:x21 |
| r1.8 | Effect on exposure to changes in interest the rates/Over twenty years | boi_met:mi1205 | xbrli:monetaryItemType | instant | boi_CS:x2 | boi_FN:x1 | N/A | boi_TI:x22 |
| r1.9 | Effect on exposure to changes in interest the rates/Without fixed maturity | boi_met:mi1205 | xbrli:monetaryItemType | instant | boi_CS:x2 | boi_FN:x1 | N/A | boi_TI:x23 |
| r1.10 | Effect on exposure to changes in interest the rates/Total fair value | boi_met:mi1205 | xbrli:monetaryItemType | instant | boi_CS:x2 | boi_FN:x1 | boi_RP:x24 | N/A |
| r1.11 | Effect on exposure to changes in interest the rates/Internal rate of return | boi_met:pi1208 | num:percentItemType | instant | boi_CS:x2 | boi_FN:x1 | boi_RP:x24 | N/A |
| r1.12 | Effect on exposure to changes in interest the rates/Average duration | boi_met:ri1209 | xbrli:decimalItemType | instant | boi_CS:x2 | boi_FN:x1 | boi_RP:x24 | N/A |
| 14.1 | Effect of other behavioral assumptions/On demand up to one month | boi_met:mi1205 | xbrli:monetaryItemType | instant | boi_CS:x2 | boi_FN:x1 | N/A | boi_TI:x14 |
| 14.2 | Effect of other behavioral assumptions/Over one month to three months | boi_met:mi1205 | xbrli:monetaryItemType | instant | boi_CS:x2 | boi_FN:x1 | N/A | boi_TI:x15 |
| 14.3 | Effect of other behavioral assumptions/Over three months to one year | boi_met:mi1205 | xbrli:monetaryItemType | instant | boi_CS:x2 | boi_FN:x1 | N/A | boi_TI:x16 |
| 14.4 | Effect of other behavioral assumptions/Over one year to three years | boi_met:mi1205 | xbrli:monetaryItemType | instant | boi_CS:x2 | boi_FN:x1 | N/A | boi_TI:x17 |
| 14.5 | Effect of other behavioral assumptions/Over three years to five years | boi_met:mi1205 | xbrli:monetaryItemType | instant | boi_CS:x2 | boi_FN:x1 | N/A | boi_TI:x18 |
| 14.6 | Effect of other behavioral assumptions/Over five years to ten years | boi_met:mi1205 | xbrli:monetaryItemType | instant | boi_CS:x2 | boi_FN:x1 | N/A | boi_TI:x20 |
| 14.7 | Effect of other behavioral assumptions/Over ten years to twenty years | boi_met:mi1205 | xbrli:monetaryItemType | instant | boi_CS:x2 | boi_FN:x1 | N/A | boi_TI:x21 |
| 14.8 | Effect of other behavioral assumptions/Over twenty years | boi_met:mi1205 | xbrli:monetaryItemType | instant | boi_CS:x2 | boi_FN:x1 | N/A | boi_TI:x22 |
| 14.9 | Effect of other behavioral assumptions/Without fixed maturity | boi_met:mi1205 | xbrli:monetaryItemType | instant | boi_CS:x2 | boi_FN:x1 | N/A | boi_TI:x23 |
| 14.10 | Effect of other behavioral assumptions/Total fair value | boi_met:mi1205 | xbrli:monetaryItemType | instant | boi_CS:x2 | boi_FN:x1 | boi_RP:x24 | N/A |
| 14.11 | Effect of other behavioral assumptions/Internal rate of return | boi_met:pi1208 | num:percentItemType | instant | boi_CS:x2 | boi_FN:x1 | boi_RP:x24 | N/A |
| 14.12 | Effect of other behavioral assumptions/Average duration | boi_met:ri1209 | xbrli:decimalItemType | instant | boi_CS:x2 | boi_FN:x1 | boi_RP:x24 | N/A |