| r0.1 | label_boi_a2/Non-indexed | boi_met:mi14 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | boi_CU:x5 | N/A | boi_EF:x7 | boi_FN:x1 | N/A | N/A | boi_RP:x24 |
| r0.2 | label_boi_a2/CPI-indexed | boi_met:mi14 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | boi_CU:x6 | N/A | boi_EF:x7 | boi_FN:x1 | N/A | N/A | boi_RP:x24 |
| r0.3 | label_boi_a2/USD | boi_met:mi14 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | boi_CU:x16 | N/A | boi_EF:x7 | boi_FN:x1 | N/A | N/A | boi_RP:x24 |
| r0.4 | label_boi_a2/Other | boi_met:mi14 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | boi_CU:x33 | N/A | boi_EF:x7 | boi_FN:x1 | N/A | N/A | boi_RP:x24 |
| r0.5 | label_boi_a2/Total | boi_met:mi14 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | N/A | boi_EF:x3 | boi_EF:x7 | boi_FN:x1 | N/A | N/A | boi_RP:x24 |
| r1.1 | The effect of changes in the interest rates on the adjusted net fair value1 of the bank and its consolidated companies/Non-indexed | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x5 | N/A | boi_EF:x7 | boi_FN:x1 | N/A | N/A | boi_RP:x24 |
| r1.2 | The effect of changes in the interest rates on the adjusted net fair value1 of the bank and its consolidated companies/CPI-indexed | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x6 | N/A | boi_EF:x7 | boi_FN:x1 | N/A | N/A | boi_RP:x24 |
| r1.3 | The effect of changes in the interest rates on the adjusted net fair value1 of the bank and its consolidated companies/USD | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x16 | N/A | boi_EF:x7 | boi_FN:x1 | N/A | N/A | boi_RP:x24 |
| r1.4 | The effect of changes in the interest rates on the adjusted net fair value1 of the bank and its consolidated companies/Other | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x33 | N/A | boi_EF:x7 | boi_FN:x1 | N/A | N/A | boi_RP:x24 |
| r1.5 | The effect of changes in the interest rates on the adjusted net fair value1 of the bank and its consolidated companies/Total | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | N/A | boi_EF:x3 | boi_EF:x7 | boi_FN:x1 | N/A | N/A | boi_RP:x24 |
| r2.1 | Parallel changes/Non-indexed | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x5 | N/A | boi_EF:x7 | boi_FN:x1 | N/A | N/A | boi_RP:x24 |
| r2.2 | Parallel changes/CPI-indexed | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x6 | N/A | boi_EF:x7 | boi_FN:x1 | N/A | N/A | boi_RP:x24 |
| r2.3 | Parallel changes/USD | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x16 | N/A | boi_EF:x7 | boi_FN:x1 | N/A | N/A | boi_RP:x24 |
| r2.4 | Parallel changes/Other | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x33 | N/A | boi_EF:x7 | boi_FN:x1 | N/A | N/A | boi_RP:x24 |
| r2.5 | Parallel changes/Total | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | N/A | boi_EF:x3 | boi_EF:x7 | boi_FN:x1 | N/A | N/A | boi_RP:x24 |
| 3.1 | A parallel increase of 1%/Non-indexed | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x5 | N/A | boi_EF:x7 | boi_FN:x1 | boi_PI:x1 | N/A | boi_RP:x24 |
| 3.2 | A parallel increase of 1%/CPI-indexed | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x6 | N/A | boi_EF:x7 | boi_FN:x1 | boi_PI:x1 | N/A | boi_RP:x24 |
| 3.3 | A parallel increase of 1%/USD | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x16 | N/A | boi_EF:x7 | boi_FN:x1 | boi_PI:x1 | N/A | boi_RP:x24 |
| 3.4 | A parallel increase of 1%/Other | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x33 | N/A | boi_EF:x7 | boi_FN:x1 | boi_PI:x1 | N/A | boi_RP:x24 |
| 3.5 | A parallel increase of 1%/Total | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | N/A | boi_EF:x3 | boi_EF:x7 | boi_FN:x1 | boi_PI:x1 | N/A | boi_RP:x24 |
| 4.1 | of which: banking portfolio/Non-indexed | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x5 | N/A | boi_EF:x7 | boi_FN:x1 | boi_PI:x1 | boi_PL:x66 | boi_RP:x24 |
| 4.2 | of which: banking portfolio/CPI-indexed | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x6 | N/A | boi_EF:x7 | boi_FN:x1 | boi_PI:x1 | boi_PL:x66 | boi_RP:x24 |
| 4.3 | of which: banking portfolio/USD | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x16 | N/A | boi_EF:x7 | boi_FN:x1 | boi_PI:x1 | boi_PL:x66 | boi_RP:x24 |
| 4.4 | of which: banking portfolio/Other | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x33 | N/A | boi_EF:x7 | boi_FN:x1 | boi_PI:x1 | boi_PL:x66 | boi_RP:x24 |
| 4.5 | of which: banking portfolio/Total | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | N/A | boi_EF:x3 | boi_EF:x7 | boi_FN:x1 | boi_PI:x1 | boi_PL:x66 | boi_RP:x24 |
| 5.1 | A parallel decline of 1%/Non-indexed | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x5 | N/A | boi_EF:x7 | boi_FN:x1 | boi_PI:x3 | N/A | boi_RP:x24 |
| 5.2 | A parallel decline of 1%/CPI-indexed | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x6 | N/A | boi_EF:x7 | boi_FN:x1 | boi_PI:x3 | N/A | boi_RP:x24 |
| 5.3 | A parallel decline of 1%/USD | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x16 | N/A | boi_EF:x7 | boi_FN:x1 | boi_PI:x3 | N/A | boi_RP:x24 |
| 5.4 | A parallel decline of 1%/Other | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x33 | N/A | boi_EF:x7 | boi_FN:x1 | boi_PI:x3 | N/A | boi_RP:x24 |
| 5.5 | A parallel decline of 1%/Total | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | N/A | boi_EF:x3 | boi_EF:x7 | boi_FN:x1 | boi_PI:x3 | N/A | boi_RP:x24 |
| 6.1 | of which: banking portfolio/Non-indexed | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x5 | N/A | boi_EF:x7 | boi_FN:x1 | boi_PI:x3 | boi_PL:x66 | boi_RP:x24 |
| 6.2 | of which: banking portfolio/CPI-indexed | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x6 | N/A | boi_EF:x7 | boi_FN:x1 | boi_PI:x3 | boi_PL:x66 | boi_RP:x24 |
| 6.3 | of which: banking portfolio/USD | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x16 | N/A | boi_EF:x7 | boi_FN:x1 | boi_PI:x3 | boi_PL:x66 | boi_RP:x24 |
| 6.4 | of which: banking portfolio/Other | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x33 | N/A | boi_EF:x7 | boi_FN:x1 | boi_PI:x3 | boi_PL:x66 | boi_RP:x24 |
| 6.5 | of which: banking portfolio/Total | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | N/A | boi_EF:x3 | boi_EF:x7 | boi_FN:x1 | boi_PI:x3 | boi_PL:x66 | boi_RP:x24 |
| r7.1 | Non-parallel changes/Non-indexed | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x5 | N/A | boi_EF:x7 | boi_FN:x1 | N/A | N/A | boi_RP:x24 |
| r7.2 | Non-parallel changes/CPI-indexed | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x6 | N/A | boi_EF:x7 | boi_FN:x1 | N/A | N/A | boi_RP:x24 |
| r7.3 | Non-parallel changes/USD | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x16 | N/A | boi_EF:x7 | boi_FN:x1 | N/A | N/A | boi_RP:x24 |
| r7.4 | Non-parallel changes/Other | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x33 | N/A | boi_EF:x7 | boi_FN:x1 | N/A | N/A | boi_RP:x24 |
| r7.5 | Non-parallel changes/Total | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | N/A | boi_EF:x3 | boi_EF:x7 | boi_FN:x1 | N/A | N/A | boi_RP:x24 |
| 7.1 | Steepening/Non-indexed | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x5 | N/A | boi_EF:x7 | boi_FN:x1 | boi_PI:x70 | N/A | boi_RP:x24 |
| 7.2 | Steepening/CPI-indexed | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x6 | N/A | boi_EF:x7 | boi_FN:x1 | boi_PI:x70 | N/A | boi_RP:x24 |
| 7.3 | Steepening/USD | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x16 | N/A | boi_EF:x7 | boi_FN:x1 | boi_PI:x70 | N/A | boi_RP:x24 |
| 7.4 | Steepening/Other | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x33 | N/A | boi_EF:x7 | boi_FN:x1 | boi_PI:x70 | N/A | boi_RP:x24 |
| 7.5 | Steepening/Total | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | N/A | boi_EF:x3 | boi_EF:x7 | boi_FN:x1 | boi_PI:x70 | N/A | boi_RP:x24 |
| 8.1 | Leveling/Non-indexed | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x5 | N/A | boi_EF:x7 | boi_FN:x1 | boi_PI:x71 | N/A | boi_RP:x24 |
| 8.2 | Leveling/CPI-indexed | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x6 | N/A | boi_EF:x7 | boi_FN:x1 | boi_PI:x71 | N/A | boi_RP:x24 |
| 8.3 | Leveling/USD | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x16 | N/A | boi_EF:x7 | boi_FN:x1 | boi_PI:x71 | N/A | boi_RP:x24 |
| 8.4 | Leveling/Other | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x33 | N/A | boi_EF:x7 | boi_FN:x1 | boi_PI:x71 | N/A | boi_RP:x24 |
| 8.5 | Leveling/Total | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | N/A | boi_EF:x3 | boi_EF:x7 | boi_FN:x1 | boi_PI:x71 | N/A | boi_RP:x24 |
| 9.1 | Interest rate increase in the short term/Non-indexed | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x5 | N/A | boi_EF:x7 | boi_FN:x1 | N/A | N/A | boi_RP:x24 |
| 9.2 | Interest rate increase in the short term/CPI-indexed | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x6 | N/A | boi_EF:x7 | boi_FN:x1 | N/A | N/A | boi_RP:x24 |
| 9.3 | Interest rate increase in the short term/USD | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x16 | N/A | boi_EF:x7 | boi_FN:x1 | N/A | N/A | boi_RP:x24 |
| 9.4 | Interest rate increase in the short term/Other | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x33 | N/A | boi_EF:x7 | boi_FN:x1 | N/A | N/A | boi_RP:x24 |
| 9.5 | Interest rate increase in the short term/Total | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | N/A | boi_EF:x3 | boi_EF:x7 | boi_FN:x1 | N/A | N/A | boi_RP:x24 |
| 10.1 | Interest rate decline in the short term/Non-indexed | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x5 | N/A | boi_EF:x7 | boi_FN:x1 | boi_PI:x73 | N/A | boi_RP:x24 |
| 10.2 | Interest rate decline in the short term/CPI-indexed | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x6 | N/A | boi_EF:x7 | boi_FN:x1 | boi_PI:x73 | N/A | boi_RP:x24 |
| 10.3 | Interest rate decline in the short term/USD | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x16 | N/A | boi_EF:x7 | boi_FN:x1 | boi_PI:x73 | N/A | boi_RP:x24 |
| 10.4 | Interest rate decline in the short term/Other | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | boi_CU:x33 | N/A | boi_EF:x7 | boi_FN:x1 | boi_PI:x73 | N/A | boi_RP:x24 |
| 10.5 | Interest rate decline in the short term/Total | boi_met:mi14 | xbrli:monetaryItemType | instant | boi_BC:x13 | boi_CS:x2 | N/A | boi_EF:x3 | boi_EF:x7 | boi_FN:x1 | boi_PI:x73 | N/A | boi_RP:x24 |