| r0.1 | label_boi_a2/Consolidated | | | | N/A | boi_CS:x2 | N/A | boi_RP:x24 | N/A | N/A |
| r0.2 | label_boi_a2/Company | | | | N/A | boi_CS:x1 | N/A | boi_RP:x24 | N/A | N/A |
| 1.1 | Businesses (1)/Consolidated | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x2 | boi_CS:x2 | boi_MC:x860 | boi_RP:x24 | N/A | boi_SE:x89 |
| 1.2 | Businesses (1)/Company | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x2 | boi_CS:x1 | boi_MC:x860 | boi_RP:x24 | N/A | boi_SE:x89 |
| 2.1 | Liabilities on account of deposits/Consolidated | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x2 | boi_CS:x2 | boi_MC:x861 | boi_RP:x24 | N/A | boi_SE:x89 |
| 2.2 | Liabilities on account of deposits/Company | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x2 | boi_CS:x1 | boi_MC:x861 | boi_RP:x24 | N/A | boi_SE:x89 |
| 3.1 | International credit card companies and organizations/Consolidated | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x2 | boi_CS:x2 | boi_MC:x862 | boi_RP:x24 | N/A | boi_SE:x89 |
| 3.2 | International credit card companies and organizations/Company | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x2 | boi_CS:x1 | boi_MC:x862 | boi_RP:x24 | N/A | boi_SE:x89 |
| 4.1 | Held (consolidated/included) companies/Consolidated | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x2 | boi_CS:x2 | boi_MC:x863 | boi_RP:x24 | N/A | boi_SE:x89 |
| 4.2 | Held (consolidated/included) companies/Company | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x2 | boi_CS:x1 | boi_MC:x863 | boi_RP:x24 | N/A | boi_SE:x89 |
| 5.1 | Advanc income/Consolidated | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x2 | boi_CS:x2 | boi_MC:x864 | boi_RP:x24 | N/A | boi_SE:x89 |
| 5.2 | Advanc income/Company | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x2 | boi_CS:x1 | boi_MC:x864 | boi_RP:x24 | N/A | boi_SE:x89 |
| 6.1 | Provision for points/stars (2)/Consolidated | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x2 | boi_CS:x2 | boi_MC:x865 | boi_RP:x24 | N/A | boi_SE:x89 |
| 6.2 | Provision for points/stars (2)/Company | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x2 | boi_CS:x1 | boi_MC:x865 | boi_RP:x24 | N/A | boi_SE:x89 |
| 7.1 | Expenses payable/Consolidated | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x2 | boi_CS:x2 | boi_MC:x866 | boi_RP:x24 | N/A | boi_SE:x89 |
| 7.2 | Expenses payable/Company | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x2 | boi_CS:x1 | boi_MC:x866 | boi_RP:x24 | N/A | boi_SE:x89 |
| 8.1 | Other/Consolidated | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x2 | boi_CS:x2 | boi_MC:x867 | boi_RP:x24 | N/A | boi_SE:x89 |
| 8.2 | Other/Company | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x2 | boi_CS:x1 | boi_MC:x867 | boi_RP:x24 | N/A | boi_SE:x89 |
| 9.1 | Total sums payable on account of credit card activity/Consolidated | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x2 | boi_CS:x2 | boi_MC:x17 | boi_RP:x24 | N/A | boi_SE:x89 |
| 9.2 | Total sums payable on account of credit card activity/Company | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x2 | boi_CS:x1 | boi_MC:x17 | boi_RP:x24 | N/A | boi_SE:x89 |
| 10.1 | Thereof: balance subtracted on account of advances to businesses (1)/Consolidated | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x2 | boi_CS:x2 | boi_MC:x586 | boi_RP:x24 | N/A | boi_SE:x89 |
| 10.2 | Thereof: balance subtracted on account of advances to businesses (1)/Company | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x2 | boi_CS:x1 | boi_MC:x586 | boi_RP:x24 | N/A | boi_SE:x89 |
| 11.1 | Thereof: balance subtracted on account of discounting of coupons to businesses/Consolidated | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x2 | boi_CS:x2 | boi_MC:x587 | boi_RP:x24 | N/A | boi_SE:x89 |
| 11.2 | Thereof: balance subtracted on account of discounting of coupons to businesses/Company | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x2 | boi_CS:x1 | boi_MC:x587 | boi_RP:x24 | N/A | boi_SE:x89 |
| 12.1 | Opening balance, points/stars (thousands)/Consolidated | boi_met:ri472 | xbrli:decimalItemType | instant | N/A | boi_CS:x2 | N/A | boi_RP:x24 | boi_RP:x22 | N/A |
| 12.2 | Opening balance, points/stars (thousands)/Company | boi_met:ri472 | xbrli:decimalItemType | instant | N/A | boi_CS:x1 | N/A | boi_RP:x24 | boi_RP:x22 | N/A |
| 13.1 | Points/stars created/Consolidated | boi_met:ri469 | xbrli:decimalItemType | instant | N/A | boi_CS:x2 | N/A | boi_RP:x24 | N/A | N/A |
| 13.2 | Points/stars created/Company | boi_met:ri469 | xbrli:decimalItemType | instant | N/A | boi_CS:x1 | N/A | boi_RP:x24 | N/A | N/A |
| 14.1 | Points/stars utilized/Consolidated | boi_met:ri470 | xbrli:decimalItemType | instant | N/A | boi_CS:x2 | N/A | boi_RP:x24 | N/A | N/A |
| 14.2 | Points/stars utilized/Company | boi_met:ri470 | xbrli:decimalItemType | instant | N/A | boi_CS:x1 | N/A | boi_RP:x24 | N/A | N/A |
| 15.1 | Points/stars expired/cancelled/Consolidated | boi_met:ri471 | xbrli:decimalItemType | instant | N/A | boi_CS:x2 | N/A | boi_RP:x24 | N/A | N/A |
| 15.2 | Points/stars expired/cancelled/Company | boi_met:ri471 | xbrli:decimalItemType | instant | N/A | boi_CS:x1 | N/A | boi_RP:x24 | N/A | N/A |
| 16.1 | Closing balance, points/stars/Consolidated | boi_met:ri472 | xbrli:decimalItemType | instant | N/A | boi_CS:x2 | N/A | boi_RP:x24 | N/A | N/A |
| 16.2 | Closing balance, points/stars/Company | boi_met:ri472 | xbrli:decimalItemType | instant | N/A | boi_CS:x1 | N/A | boi_RP:x24 | N/A | N/A |