| r0.1 | label_boi_a2/Controlling principals | boi_met:md13 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | boi_IP:x5 | N/A | boi_MU:x1 | boi_RP:x25 |
| r0.2 | label_boi_a2/Other | boi_met:md13 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | boi_IP:x19 | N/A | boi_MU:x1 | boi_RP:x25 |
| r0.3 | label_boi_a2/Management key people | boi_met:md13 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | boi_IP:x3 | N/A | boi_MU:x1 | boi_RP:x25 |
| r0.4 | label_boi_a2/Others | boi_met:md13 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | boi_IP:x21 | N/A | boi_MU:x1 | boi_RP:x25 |
| r0.5 | label_boi_a2/Non-consolidated companies | boi_met:md13 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | boi_IP:x9 | N/A | boi_MU:x1 | boi_RP:x25 |
| r0.6 | label_boi_a2/Companies included or held under joint control | boi_met:md13 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | boi_IP:x22 | N/A | boi_MU:x1 | boi_RP:x25 |
| r0.7 | label_boi_a2/Other | boi_met:md13 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | boi_IP:x25 | N/A | boi_MU:x1 | boi_RP:x25 |
| 1.1 | Income from credit card transactions/Controlling principals | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | boi_IP:x5 | boi_MC:x281 | boi_MU:x1 | boi_RP:x25 |
| 1.2 | Income from credit card transactions/Other | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | boi_IP:x19 | boi_MC:x281 | boi_MU:x1 | boi_RP:x25 |
| 1.3 | Income from credit card transactions/Management key people | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | boi_IP:x3 | boi_MC:x281 | boi_MU:x1 | boi_RP:x25 |
| 1.4 | Income from credit card transactions/Others | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | boi_IP:x21 | boi_MC:x281 | boi_MU:x1 | boi_RP:x25 |
| 1.5 | Income from credit card transactions/Non-consolidated companies | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | boi_IP:x9 | boi_MC:x281 | boi_MU:x1 | boi_RP:x25 |
| 1.6 | Income from credit card transactions/Companies included or held under joint control | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | boi_IP:x22 | boi_MC:x281 | boi_MU:x1 | boi_RP:x25 |
| 1.7 | Income from credit card transactions/Other | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | boi_IP:x25 | boi_MC:x281 | boi_MU:x1 | boi_RP:x25 |
| 2.1 | Profit from financing activity before credit loss provision/Controlling principals | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | boi_IP:x5 | boi_MC:x125 | boi_MU:x1 | boi_RP:x25 |
| 2.2 | Profit from financing activity before credit loss provision/Other | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | boi_IP:x19 | boi_MC:x125 | boi_MU:x1 | boi_RP:x25 |
| 2.3 | Profit from financing activity before credit loss provision/Management key people | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | boi_IP:x3 | boi_MC:x125 | boi_MU:x1 | boi_RP:x25 |
| 2.4 | Profit from financing activity before credit loss provision/Others | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | boi_IP:x21 | boi_MC:x125 | boi_MU:x1 | boi_RP:x25 |
| 2.5 | Profit from financing activity before credit loss provision/Non-consolidated companies | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | boi_IP:x9 | boi_MC:x125 | boi_MU:x1 | boi_RP:x25 |
| 2.6 | Profit from financing activity before credit loss provision/Companies included or held under joint control | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | boi_IP:x22 | boi_MC:x125 | boi_MU:x1 | boi_RP:x25 |
| 2.7 | Profit from financing activity before credit loss provision/Other | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | boi_IP:x25 | boi_MC:x125 | boi_MU:x1 | boi_RP:x25 |
| 3.1 | Credit loss expenses/Controlling principals | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x12 | boi_CS:x2 | boi_IP:x5 | boi_MC:x126 | boi_MU:x1 | boi_RP:x25 |
| 3.2 | Credit loss expenses/Other | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x12 | boi_CS:x2 | boi_IP:x19 | boi_MC:x126 | boi_MU:x1 | boi_RP:x25 |
| 3.3 | Credit loss expenses/Management key people | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x12 | boi_CS:x2 | boi_IP:x3 | boi_MC:x126 | boi_MU:x1 | boi_RP:x25 |
| 3.4 | Credit loss expenses/Others | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x12 | boi_CS:x2 | boi_IP:x21 | boi_MC:x126 | boi_MU:x1 | boi_RP:x25 |
| 3.5 | Credit loss expenses/Non-consolidated companies | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x12 | boi_CS:x2 | boi_IP:x9 | boi_MC:x126 | boi_MU:x1 | boi_RP:x25 |
| 3.6 | Credit loss expenses/Companies included or held under joint control | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x12 | boi_CS:x2 | boi_IP:x22 | boi_MC:x126 | boi_MU:x1 | boi_RP:x25 |
| 3.7 | Credit loss expenses/Other | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x12 | boi_CS:x2 | boi_IP:x25 | boi_MC:x126 | boi_MU:x1 | boi_RP:x25 |
| 4.1 | Other income/Controlling principals | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | boi_IP:x5 | boi_MC:x456 | boi_MU:x1 | boi_RP:x25 |
| 4.2 | Other income/Other | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | boi_IP:x19 | boi_MC:x456 | boi_MU:x1 | boi_RP:x25 |
| 4.3 | Other income/Management key people | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | boi_IP:x3 | boi_MC:x456 | boi_MU:x1 | boi_RP:x25 |
| 4.4 | Other income/Others | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | boi_IP:x21 | boi_MC:x456 | boi_MU:x1 | boi_RP:x25 |
| 4.5 | Other income/Non-consolidated companies | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | boi_IP:x9 | boi_MC:x456 | boi_MU:x1 | boi_RP:x25 |
| 4.6 | Other income/Companies included or held under joint control | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | boi_IP:x22 | boi_MC:x456 | boi_MU:x1 | boi_RP:x25 |
| 4.7 | Other income/Other | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | boi_IP:x25 | boi_MC:x456 | boi_MU:x1 | boi_RP:x25 |
| 5.1 | Operational expenses/Controlling principals | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x10 | boi_CS:x2 | boi_IP:x5 | boi_MC:x458 | boi_MU:x1 | boi_RP:x25 |
| 5.2 | Operational expenses/Other | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x10 | boi_CS:x2 | boi_IP:x19 | boi_MC:x458 | boi_MU:x1 | boi_RP:x25 |
| 5.3 | Operational expenses/Management key people | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x10 | boi_CS:x2 | boi_IP:x3 | boi_MC:x458 | boi_MU:x1 | boi_RP:x25 |
| 5.4 | Operational expenses/Others | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x10 | boi_CS:x2 | boi_IP:x21 | boi_MC:x458 | boi_MU:x1 | boi_RP:x25 |
| 5.5 | Operational expenses/Non-consolidated companies | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x10 | boi_CS:x2 | boi_IP:x9 | boi_MC:x458 | boi_MU:x1 | boi_RP:x25 |
| 5.6 | Operational expenses/Companies included or held under joint control | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x10 | boi_CS:x2 | boi_IP:x22 | boi_MC:x458 | boi_MU:x1 | boi_RP:x25 |
| 5.7 | Operational expenses/Other | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x10 | boi_CS:x2 | boi_IP:x25 | boi_MC:x458 | boi_MU:x1 | boi_RP:x25 |
| 6.1 | Sales and marketing expenses/Controlling principals | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x10 | boi_CS:x2 | boi_IP:x5 | boi_MC:x459 | boi_MU:x1 | boi_RP:x25 |
| 6.2 | Sales and marketing expenses/Other | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x10 | boi_CS:x2 | boi_IP:x19 | boi_MC:x459 | boi_MU:x1 | boi_RP:x25 |
| 6.3 | Sales and marketing expenses/Management key people | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x10 | boi_CS:x2 | boi_IP:x3 | boi_MC:x459 | boi_MU:x1 | boi_RP:x25 |
| 6.4 | Sales and marketing expenses/Others | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x10 | boi_CS:x2 | boi_IP:x21 | boi_MC:x459 | boi_MU:x1 | boi_RP:x25 |
| 6.5 | Sales and marketing expenses/Non-consolidated companies | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x10 | boi_CS:x2 | boi_IP:x9 | boi_MC:x459 | boi_MU:x1 | boi_RP:x25 |
| 6.6 | Sales and marketing expenses/Companies included or held under joint control | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x10 | boi_CS:x2 | boi_IP:x22 | boi_MC:x459 | boi_MU:x1 | boi_RP:x25 |
| 6.7 | Sales and marketing expenses/Other | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x10 | boi_CS:x2 | boi_IP:x25 | boi_MC:x459 | boi_MU:x1 | boi_RP:x25 |
| 7.1 | Administrative and general expenses/Controlling principals | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x10 | boi_CS:x2 | boi_IP:x5 | boi_MC:x460 | boi_MU:x1 | boi_RP:x25 |
| 7.2 | Administrative and general expenses/Other | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x10 | boi_CS:x2 | boi_IP:x19 | boi_MC:x460 | boi_MU:x1 | boi_RP:x25 |
| 7.3 | Administrative and general expenses/Management key people | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x10 | boi_CS:x2 | boi_IP:x3 | boi_MC:x460 | boi_MU:x1 | boi_RP:x25 |
| 7.4 | Administrative and general expenses/Others | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x10 | boi_CS:x2 | boi_IP:x21 | boi_MC:x460 | boi_MU:x1 | boi_RP:x25 |
| 7.5 | Administrative and general expenses/Non-consolidated companies | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x10 | boi_CS:x2 | boi_IP:x9 | boi_MC:x460 | boi_MU:x1 | boi_RP:x25 |
| 7.6 | Administrative and general expenses/Companies included or held under joint control | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x10 | boi_CS:x2 | boi_IP:x22 | boi_MC:x460 | boi_MU:x1 | boi_RP:x25 |
| 7.7 | Administrative and general expenses/Other | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x10 | boi_CS:x2 | boi_IP:x25 | boi_MC:x460 | boi_MU:x1 | boi_RP:x25 |
| 8.1 | Payments to banks/Controlling principals | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x10 | boi_CS:x2 | boi_IP:x5 | boi_MC:x461 | boi_MU:x1 | boi_RP:x25 |
| 8.2 | Payments to banks/Other | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x10 | boi_CS:x2 | boi_IP:x19 | boi_MC:x461 | boi_MU:x1 | boi_RP:x25 |
| 8.3 | Payments to banks/Management key people | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x10 | boi_CS:x2 | boi_IP:x3 | boi_MC:x461 | boi_MU:x1 | boi_RP:x25 |
| 8.4 | Payments to banks/Others | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x10 | boi_CS:x2 | boi_IP:x21 | boi_MC:x461 | boi_MU:x1 | boi_RP:x25 |
| 8.5 | Payments to banks/Non-consolidated companies | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x10 | boi_CS:x2 | boi_IP:x9 | boi_MC:x461 | boi_MU:x1 | boi_RP:x25 |
| 8.6 | Payments to banks/Companies included or held under joint control | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x10 | boi_CS:x2 | boi_IP:x22 | boi_MC:x461 | boi_MU:x1 | boi_RP:x25 |
| 8.7 | Payments to banks/Other | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x10 | boi_CS:x2 | boi_IP:x25 | boi_MC:x461 | boi_MU:x1 | boi_RP:x25 |
| 9.1 | Total/Controlling principals | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | boi_IP:x5 | boi_MC:x123 | boi_MU:x1 | boi_RP:x25 |
| 9.2 | Total/Other | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | boi_IP:x19 | boi_MC:x123 | boi_MU:x1 | boi_RP:x25 |
| 9.3 | Total/Management key people | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | boi_IP:x3 | boi_MC:x123 | boi_MU:x1 | boi_RP:x25 |
| 9.4 | Total/Others | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | boi_IP:x21 | boi_MC:x123 | boi_MU:x1 | boi_RP:x25 |
| 9.5 | Total/Non-consolidated companies | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | boi_IP:x9 | boi_MC:x123 | boi_MU:x1 | boi_RP:x25 |
| 9.6 | Total/Companies included or held under joint control | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | boi_IP:x22 | boi_MC:x123 | boi_MU:x1 | boi_RP:x25 |
| 9.7 | Total/Other | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | boi_IP:x25 | boi_MC:x123 | boi_MU:x1 | boi_RP:x25 |