| r0.1 | label_boi_a2/On bonds available for sale | | | | N/A | N/A | boi_CS:x2 | boi_MC:x399 | N/A | boi_PL:x1 | boi_RP:x25 | N/A |
| r0.2 | label_boi_a2/Translation adjastment, net after the effect of hedges | | | | N/A | N/A | boi_CS:x2 | boi_MC:x399 | N/A | boi_PL:x30 | boi_RP:x25 | N/A |
| r0.3 | label_boi_a2/Earnings (losses) on cash flow hedges | | | | N/A | N/A | boi_CS:x2 | boi_MC:x399 | N/A | boi_PL:x27 | boi_RP:x25 | N/A |
| r0.4 | label_boi_a2/Reconciliations in respect of employee rights | | | | N/A | N/A | boi_CS:x2 | boi_MC:x399 | N/A | boi_PL:x53 | boi_RP:x25 | N/A |
| r0.5 | label_boi_a2/Total | | | | N/A | N/A | boi_CS:x2 | boi_MC:x399 | N/A | boi_PL:x36 | boi_RP:x25 | N/A |
| r0.6 | label_boi_a2/Other comprehensive income attributable to non-controlling interests | | | | N/A | boi_CN:x2 | boi_CS:x2 | boi_MC:x399 | N/A | boi_PL:x36 | boi_RP:x25 | N/A |
| r0.7 | label_boi_a2/Other comprehensive income attributable to non-controlling interest | | | | N/A | boi_CN:x1 | boi_CS:x2 | boi_MC:x399 | N/A | boi_PL:x36 | boi_RP:x25 | N/A |
| 1.1 | Balance at beginning of year/On bonds available for sale | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x3 | N/A | boi_CS:x2 | boi_MC:x399 | N/A | boi_PL:x1 | boi_RP:x25 | boi_RP:x22 |
| 1.2 | Balance at beginning of year/Translation adjastment, net after the effect of hedges | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x3 | N/A | boi_CS:x2 | boi_MC:x399 | N/A | boi_PL:x30 | boi_RP:x25 | boi_RP:x22 |
| 1.3 | Balance at beginning of year/Earnings (losses) on cash flow hedges | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x3 | N/A | boi_CS:x2 | boi_MC:x399 | N/A | boi_PL:x27 | boi_RP:x25 | boi_RP:x22 |
| 1.4 | Balance at beginning of year/Reconciliations in respect of employee rights | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x3 | N/A | boi_CS:x2 | boi_MC:x399 | N/A | boi_PL:x53 | boi_RP:x25 | boi_RP:x22 |
| 1.5 | Balance at beginning of year/Total | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x3 | N/A | boi_CS:x2 | boi_MC:x399 | N/A | boi_PL:x36 | boi_RP:x25 | boi_RP:x22 |
| 1.6 | Balance at beginning of year/Other comprehensive income attributable to non-controlling interests | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x3 | boi_CN:x2 | boi_CS:x2 | boi_MC:x399 | N/A | boi_PL:x36 | boi_RP:x25 | boi_RP:x22 |
| 1.7 | Balance at beginning of year/Other comprehensive income attributable to non-controlling interest | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x3 | boi_CN:x1 | boi_CS:x2 | boi_MC:x399 | N/A | boi_PL:x36 | boi_RP:x25 | boi_RP:x22 |
| 2.1 | Changes during the year/On bonds available for sale | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x399 | boi_MU:x1 | boi_PL:x1 | boi_RP:x25 | N/A |
| 2.2 | Changes during the year/Translation adjastment, net after the effect of hedges | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x399 | boi_MU:x1 | boi_PL:x30 | boi_RP:x25 | N/A |
| 2.3 | Changes during the year/Earnings (losses) on cash flow hedges | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x399 | boi_MU:x1 | boi_PL:x27 | boi_RP:x25 | N/A |
| 2.4 | Changes during the year/Reconciliations in respect of employee rights | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x399 | boi_MU:x1 | boi_PL:x53 | boi_RP:x25 | N/A |
| 2.5 | Changes during the year/Total | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | N/A | boi_CS:x2 | boi_MC:x399 | boi_MU:x1 | boi_PL:x36 | boi_RP:x25 | N/A |
| 2.6 | Changes during the year/Other comprehensive income attributable to non-controlling interests | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CN:x2 | boi_CS:x2 | boi_MC:x399 | boi_MU:x1 | boi_PL:x36 | boi_RP:x25 | N/A |
| 2.7 | Changes during the year/Other comprehensive income attributable to non-controlling interest | boi_met:md13 | xbrli:monetaryItemType | instant | boi_BC:x11 | boi_CN:x1 | boi_CS:x2 | boi_MC:x399 | boi_MU:x1 | boi_PL:x36 | boi_RP:x25 | N/A |
| 3.1 | Balance at end of year/On bonds available for sale | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x3 | N/A | boi_CS:x2 | boi_MC:x399 | N/A | boi_PL:x1 | boi_RP:x25 | N/A |
| 3.2 | Balance at end of year/Translation adjastment, net after the effect of hedges | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x3 | N/A | boi_CS:x2 | boi_MC:x399 | N/A | boi_PL:x30 | boi_RP:x25 | N/A |
| 3.3 | Balance at end of year/Earnings (losses) on cash flow hedges | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x3 | N/A | boi_CS:x2 | boi_MC:x399 | N/A | boi_PL:x27 | boi_RP:x25 | N/A |
| 3.4 | Balance at end of year/Reconciliations in respect of employee rights | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x3 | N/A | boi_CS:x2 | boi_MC:x399 | N/A | boi_PL:x53 | boi_RP:x25 | N/A |
| 3.5 | Balance at end of year/Total | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x3 | N/A | boi_CS:x2 | boi_MC:x399 | N/A | boi_PL:x36 | boi_RP:x25 | N/A |
| 3.6 | Balance at end of year/Other comprehensive income attributable to non-controlling interests | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x3 | boi_CN:x2 | boi_CS:x2 | boi_MC:x399 | N/A | boi_PL:x36 | boi_RP:x25 | N/A |
| 3.7 | Balance at end of year/Other comprehensive income attributable to non-controlling interest | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x3 | boi_CN:x1 | boi_CS:x2 | boi_MC:x399 | N/A | boi_PL:x36 | boi_RP:x25 | N/A |