| r0.1 | label_boi_a2/Year -1 | | | | N/A | boi_CS:x2 | N/A | boi_RP:x24 |
| r1.1 | On-balance sheet exposures/Year -1 | | | | N/A | boi_CS:x2 | N/A | boi_RP:x24 |
| 1.1 | On-balance sheet items (excluding derivatives and securities financing transactions, but including collateral)/Year -1 | boi_met:mi1285 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | N/A | boi_RP:x24 |
| 2.1 | Asset amounts deducted in determining Tier 1 capital/Year -1 | boi_met:mi1286 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | N/A | boi_RP:x24 |
| 3.1 | Total on-balance sheet exposures/Year -1 | boi_met:mi1284 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | N/A | boi_RP:x24 |
| r5.1 | Derivative exposures/Year -1 | | | | N/A | boi_CS:x2 | N/A | boi_RP:x24 |
| 4.1 | Replacement cost associated with all derivatives transactions/Year -1 | boi_met:mi1288 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | N/A | boi_RP:x24 |
| 5.1 | Add-on amounts for potential future exposure associated with all derivatives transactions/Year -1 | boi_met:mi1289 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | N/A | boi_RP:x24 |
| 6.1 | Gross-up for collateral provided in respect of derivatives deducted from balance sheet assets pursuant to the Public Reporting Directives/Year -1 | boi_met:mi1290 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | N/A | boi_RP:x24 |
| 7.1 | Deductions of receivables assets for cash variation margin provided in derivatives transactions/Year -1 | boi_met:mi1291 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | N/A | boi_RP:x24 |
| 8.1 | Exempted central counterparty leg of client-cleared trade exposures/Year -1 | boi_met:mi1292 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | N/A | boi_RP:x24 |
| 9.1 | Adjusted effective notional amount of written credit derivatives/Year -1 | boi_met:mi1293 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | N/A | boi_RP:x24 |
| 10.1 | Adjusted effective notional offsets and add-on deductions for written credit derivatives - -/Year -1 | boi_met:mi1294 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | N/A | boi_RP:x24 |
| 11.1 | Total derivative exposures/Year -1 | boi_met:mi1287 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | N/A | boi_RP:x24 |
| r14.1 | Securities financing transaction exposures/Year -1 | | | | N/A | boi_CS:x2 | N/A | boi_RP:x24 |
| 12.1 | Gross securities financing transaction assets (with no recognition of netting), after adjusting for sale accounting transactions/Year -1 | boi_met:mi1296 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | N/A | boi_RP:x24 |
| 13.1 | Netted amounts of cash payables and cash receivables of gross securities financing transaction assets/Year -1 | boi_met:mi1297 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | N/A | boi_RP:x24 |
| 14.1 | Central counterparty credit risk exposure for securities financing transaction assets/Year -1 | boi_met:mi1298 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | N/A | boi_RP:x24 |
| 15.1 | Agent transaction exposures/Year -1 | boi_met:mi1299 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | N/A | boi_RP:x24 |
| 16.1 | Total securities financing transaction exposures/Year -1 | boi_met:mi1295 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | N/A | boi_RP:x24 |
| r20.1 | Other off-balance sheet exposures/Year -1 | | | | N/A | boi_CS:x2 | N/A | boi_RP:x24 |
| 17.1 | Off-balance sheet exposure at gross notional amount/Year -1 | boi_met:mi1301 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | N/A | boi_RP:x24 |
| 18.1 | Adjustments for conversion to credit equivalent amounts/Year -1 | boi_met:mi1302 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | N/A | boi_RP:x24 |
| 19.1 | Off-balance sheet items/Year -1 | boi_met:mi1300 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | N/A | boi_RP:x24 |
| r24.1 | Capital and total exposures/Year -1 | | | | N/A | boi_CS:x2 | N/A | boi_RP:x24 |
| 20.1 | Tier 1 capital/Year -1 | boi_met:mi15 | xbrli:monetaryItemType | instant | boi_BC:x15 | boi_CS:x2 | boi_MC:x596 | boi_RP:x24 |
| 21.1 | Total exposures/Year -1 | boi_met:mi902 | xbrli:monetaryItemType | instant | N/A | boi_CS:x2 | N/A | boi_RP:x24 |
| r27.1 | Leverage ratio/Year -1 | | | | N/A | boi_CS:x2 | N/A | boi_RP:x24 |
| 22.1 | Leverage ratio pursuant to Proper Conduct of Banking Business Directive 218/Year -1 | boi_met:pi903 | num:percentItemType | instant | N/A | boi_CS:x2 | N/A | boi_RP:x24 |