| r0.1 | label_boi_a2/Unaudited | boi_met:md13 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | N/A | N/A | N/A | boi_RP:x19 |
| r0.2 | label_boi_a2/Unaudited | boi_met:md13 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | N/A | N/A | boi_MU:x1 | boi_RP:x3 |
| r1.1 | Income from businesses/Unaudited | boi_met:md13 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | N/A | N/A | N/A | boi_RP:x19 |
| r1.2 | Income from businesses/Unaudited | boi_met:md13 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | N/A | N/A | boi_MU:x1 | boi_RP:x3 |
| 1.1 | Businesses' fees/Unaudited | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | boi_CS:x2 | N/A | boi_MC:x464 | N/A | boi_RP:x19 |
| 1.2 | Businesses' fees/Unaudited | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | boi_CS:x2 | N/A | boi_MC:x464 | boi_MU:x1 | boi_RP:x3 |
| 2.1 | Other income/Unaudited | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | boi_CS:x2 | N/A | boi_MC:x465 | N/A | boi_RP:x19 |
| 2.2 | Other income/Unaudited | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | boi_CS:x2 | N/A | boi_MC:x465 | boi_MU:x1 | boi_RP:x3 |
| 3.1 | Total income from businesses, gross/Unaudited | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | boi_CS:x2 | N/A | boi_MC:x463 | N/A | boi_RP:x19 |
| 3.2 | Total income from businesses, gross/Unaudited | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | boi_CS:x2 | N/A | boi_MC:x463 | boi_MU:x1 | boi_RP:x3 |
| 4.1 | Minus fees to other issuers/Unaudited | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x10 | boi_CS:x2 | N/A | boi_MC:x466 | N/A | boi_RP:x19 |
| 4.2 | Minus fees to other issuers/Unaudited | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x10 | boi_CS:x2 | N/A | boi_MC:x466 | boi_MU:x1 | boi_RP:x3 |
| 5.1 | Total income from businesses, net/Unaudited | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | N/A | boi_MC:x462 | N/A | boi_RP:x19 |
| 5.2 | Total income from businesses, net/Unaudited | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | N/A | boi_MC:x462 | boi_MU:x1 | boi_RP:x3 |
| r7.1 | Income from credit card holders/Unaudited | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | boi_CS:x2 | N/A | N/A | N/A | boi_RP:x19 |
| r7.2 | Income from credit card holders/Unaudited | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | boi_CS:x2 | N/A | N/A | boi_MU:x1 | boi_RP:x3 |
| 6.1 | Issuer's fees/Unaudited | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | boi_CS:x2 | boi_GA:x1 | boi_MC:x468 | N/A | boi_RP:x19 |
| 6.2 | Issuer's fees/Unaudited | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | boi_CS:x2 | boi_GA:x1 | boi_MC:x468 | boi_MU:x1 | boi_RP:x3 |
| 7.1 | Service fees/Unaudited | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | boi_CS:x2 | boi_GA:x1 | boi_MC:x469 | N/A | boi_RP:x19 |
| 7.2 | Service fees/Unaudited | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | boi_CS:x2 | boi_GA:x1 | boi_MC:x469 | boi_MU:x1 | boi_RP:x3 |
| 8.1 | Fees from transactions abroad/Unaudited | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | boi_CS:x2 | boi_GA:x2 | boi_MC:x467 | N/A | boi_RP:x19 |
| 8.2 | Fees from transactions abroad/Unaudited | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | boi_CS:x2 | boi_GA:x2 | boi_MC:x467 | boi_MU:x1 | boi_RP:x3 |
| 9.1 | Total income from credit card holders/Unaudited | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | boi_CS:x2 | N/A | boi_MC:x467 | N/A | boi_RP:x19 |
| 9.2 | Total income from credit card holders/Unaudited | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x9 | boi_CS:x2 | N/A | boi_MC:x467 | boi_MU:x1 | boi_RP:x3 |
| 10.1 | Total income from credit card transactions/Unaudited | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | N/A | boi_MC:x281 | N/A | boi_RP:x19 |
| 10.2 | Total income from credit card transactions/Unaudited | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CS:x2 | N/A | boi_MC:x281 | boi_MU:x1 | boi_RP:x3 |