| r0.1 | label_boi_a2/Average balance | boi_met:md86 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | N/A | boi_GA:x1 | N/A | N/A | N/A | N/A | boi_RP:x19 |
| r0.2 | label_boi_a2/Financing income (expenses) | boi_met:md13 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | N/A | boi_GA:x1 | boi_MC:x125 | N/A | N/A | N/A | boi_RP:x19 |
| r0.3 | label_boi_a2/Rate of income (expense) | boi_met:pd90 | num:percentItemType | instant | N/A | boi_CS:x2 | N/A | boi_GA:x1 | N/A | N/A | N/A | N/A | boi_RP:x19 |
| r0.4 | label_boi_a2/Average balance | boi_met:md86 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | N/A | boi_GA:x1 | N/A | N/A | N/A | boi_MU:x1 | boi_RP:x19 |
| r0.5 | label_boi_a2/Financing income (expenses) | boi_met:md13 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | N/A | boi_GA:x1 | boi_MC:x125 | N/A | N/A | boi_MU:x1 | boi_RP:x19 |
| r0.6 | label_boi_a2/Rate of income (expense) | boi_met:pd90 | num:percentItemType | instant | N/A | boi_CS:x2 | N/A | boi_GA:x1 | N/A | N/A | N/A | boi_MU:x1 | boi_RP:x19 |
| r1.1 | Unindexed local currency/Average balance | boi_met:md86 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | boi_CU:x5 | boi_GA:x1 | N/A | boi_MC:x962 | N/A | N/A | boi_RP:x19 |
| r1.2 | Unindexed local currency/Financing income (expenses) | boi_met:md13 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | boi_CU:x5 | boi_GA:x1 | boi_MC:x125 | boi_MC:x962 | N/A | N/A | boi_RP:x19 |
| r1.3 | Unindexed local currency/Rate of income (expense) | boi_met:pd90 | num:percentItemType | instant | N/A | boi_CS:x2 | boi_CU:x5 | boi_GA:x1 | N/A | boi_MC:x962 | N/A | N/A | boi_RP:x19 |
| r1.4 | Unindexed local currency/Average balance | boi_met:md86 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | boi_CU:x5 | boi_GA:x1 | N/A | boi_MC:x962 | N/A | boi_MU:x1 | boi_RP:x19 |
| r1.5 | Unindexed local currency/Financing income (expenses) | boi_met:md13 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | boi_CU:x5 | boi_GA:x1 | boi_MC:x125 | boi_MC:x962 | N/A | boi_MU:x1 | boi_RP:x19 |
| r1.6 | Unindexed local currency/Rate of income (expense) | boi_met:pd90 | num:percentItemType | instant | N/A | boi_CS:x2 | boi_CU:x5 | boi_GA:x1 | N/A | boi_MC:x962 | N/A | boi_MU:x1 | boi_RP:x19 |
| 1.1 | Total interest-bearing assets/Average balance | boi_met:md86 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_CU:x5 | boi_GA:x1 | N/A | boi_MC:x962 | boi_MC:x1 | N/A | boi_RP:x19 |
| 1.2 | Total interest-bearing assets/Financing income (expenses) | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_CU:x5 | boi_GA:x1 | boi_MC:x125 | boi_MC:x962 | boi_MC:x1 | N/A | boi_RP:x19 |
| 1.3 | Total interest-bearing assets/Rate of income (expense) | boi_met:pd90 | num:percentItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_CU:x5 | boi_GA:x1 | N/A | boi_MC:x962 | boi_MC:x1 | N/A | boi_RP:x19 |
| 1.4 | Total interest-bearing assets/Average balance | boi_met:md86 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_CU:x5 | boi_GA:x1 | N/A | boi_MC:x962 | boi_MC:x1 | boi_MU:x1 | boi_RP:x19 |
| 1.5 | Total interest-bearing assets/Financing income (expenses) | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_CU:x5 | boi_GA:x1 | boi_MC:x125 | boi_MC:x962 | boi_MC:x1 | boi_MU:x1 | boi_RP:x19 |
| 1.6 | Total interest-bearing assets/Rate of income (expense) | boi_met:pd90 | num:percentItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_CU:x5 | boi_GA:x1 | N/A | boi_MC:x962 | boi_MC:x1 | boi_MU:x1 | boi_RP:x19 |
| 2.1 | Total interest-bearing liabilities/Average balance | boi_met:md86 | xbrli:monetaryItemType | instant | boi_BC:x2 | boi_CS:x2 | boi_CU:x5 | boi_GA:x1 | N/A | boi_MC:x962 | boi_MC:x3 | N/A | boi_RP:x19 |
| 2.2 | Total interest-bearing liabilities/Financing income (expenses) | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x2 | boi_CS:x2 | boi_CU:x5 | boi_GA:x1 | boi_MC:x125 | boi_MC:x962 | boi_MC:x3 | N/A | boi_RP:x19 |
| 2.3 | Total interest-bearing liabilities/Rate of income (expense) | boi_met:pd90 | num:percentItemType | instant | boi_BC:x2 | boi_CS:x2 | boi_CU:x5 | boi_GA:x1 | N/A | boi_MC:x962 | boi_MC:x3 | N/A | boi_RP:x19 |
| 2.4 | Total interest-bearing liabilities/Average balance | boi_met:md86 | xbrli:monetaryItemType | instant | boi_BC:x2 | boi_CS:x2 | boi_CU:x5 | boi_GA:x1 | N/A | boi_MC:x962 | boi_MC:x3 | boi_MU:x1 | boi_RP:x19 |
| 2.5 | Total interest-bearing liabilities/Financing income (expenses) | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x2 | boi_CS:x2 | boi_CU:x5 | boi_GA:x1 | boi_MC:x125 | boi_MC:x962 | boi_MC:x3 | boi_MU:x1 | boi_RP:x19 |
| 2.6 | Total interest-bearing liabilities/Rate of income (expense) | boi_met:pd90 | num:percentItemType | instant | boi_BC:x2 | boi_CS:x2 | boi_CU:x5 | boi_GA:x1 | N/A | boi_MC:x962 | boi_MC:x3 | boi_MU:x1 | boi_RP:x19 |