| r0.1 | label_boi_a2/Total | boi_met:mi2 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | N/A | boi_CS:x2 | N/A | boi_MC:x8 | N/A | N/A | boi_RP:x24 |
| r0.2 | label_boi_a2/of which: bullet and balloon | boi_met:mi2 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | N/A | boi_CS:x2 | N/A | boi_MC:x8 | boi_PI:x24 | N/A | boi_RP:x24 |
| r0.3 | label_boi_a2/of which: variable interest | boi_met:mi2 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | N/A | boi_CS:x2 | boi_CU:x24 | boi_MC:x8 | N/A | N/A | boi_RP:x24 |
| r0.4 | label_boi_a2/Off-balance sheet credit risk total | boi_met:mi184 | xbrli:monetaryItemType | instant | N/A | boi_CL:x35 | N/A | boi_CS:x2 | N/A | N/A | N/A | N/A | boi_RP:x24 |
| r1.1 | First charge: rate of financing:/Total | boi_met:mi2 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CL:x29 | boi_CS:x2 | N/A | boi_MC:x8 | N/A | N/A | boi_RP:x24 |
| r1.2 | First charge: rate of financing:/of which: bullet and balloon | boi_met:mi2 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CL:x29 | boi_CS:x2 | N/A | boi_MC:x8 | boi_PI:x24 | N/A | boi_RP:x24 |
| r1.3 | First charge: rate of financing:/of which: variable interest | boi_met:mi2 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CL:x29 | boi_CS:x2 | boi_CU:x24 | boi_MC:x8 | N/A | N/A | boi_RP:x24 |
| r1.4 | First charge: rate of financing:/Off-balance sheet credit risk total | boi_met:mi184 | xbrli:monetaryItemType | instant | N/A | boi_CL:x35 | boi_CL:x29 | boi_CS:x2 | N/A | N/A | N/A | N/A | boi_RP:x24 |
| 1.1 | Up to 60%/Total | boi_met:mi2 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CL:x29 | boi_CS:x2 | N/A | boi_MC:x8 | N/A | boi_PI:x36 | boi_RP:x24 |
| 1.2 | Up to 60%/of which: bullet and balloon | boi_met:mi2 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CL:x29 | boi_CS:x2 | N/A | boi_MC:x8 | boi_PI:x24 | boi_PI:x36 | boi_RP:x24 |
| 1.3 | Up to 60%/of which: variable interest | boi_met:mi2 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CL:x29 | boi_CS:x2 | boi_CU:x24 | boi_MC:x8 | N/A | boi_PI:x36 | boi_RP:x24 |
| 1.4 | Up to 60%/Off-balance sheet credit risk total | boi_met:mi184 | xbrli:monetaryItemType | instant | N/A | boi_CL:x35 | boi_CL:x29 | boi_CS:x2 | N/A | N/A | N/A | boi_PI:x36 | boi_RP:x24 |
| 2.1 | Above 60%/Total | boi_met:mi2 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CL:x29 | boi_CS:x2 | N/A | boi_MC:x8 | N/A | boi_PI:x37 | boi_RP:x24 |
| 2.2 | Above 60%/of which: bullet and balloon | boi_met:mi2 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CL:x29 | boi_CS:x2 | N/A | boi_MC:x8 | boi_PI:x24 | boi_PI:x37 | boi_RP:x24 |
| 2.3 | Above 60%/of which: variable interest | boi_met:mi2 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CL:x29 | boi_CS:x2 | boi_CU:x24 | boi_MC:x8 | N/A | boi_PI:x37 | boi_RP:x24 |
| 2.4 | Above 60%/Off-balance sheet credit risk total | boi_met:mi184 | xbrli:monetaryItemType | instant | N/A | boi_CL:x35 | boi_CL:x29 | boi_CS:x2 | N/A | N/A | N/A | boi_PI:x37 | boi_RP:x24 |
| 3.1 | Second or without charge/Total | boi_met:mi2 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CL:x30 | boi_CS:x2 | N/A | boi_MC:x8 | N/A | N/A | boi_RP:x24 |
| 3.2 | Second or without charge/of which: bullet and balloon | boi_met:mi2 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CL:x30 | boi_CS:x2 | N/A | boi_MC:x8 | boi_PI:x24 | N/A | boi_RP:x24 |
| 3.3 | Second or without charge/of which: variable interest | boi_met:mi2 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | boi_CL:x30 | boi_CS:x2 | boi_CU:x24 | boi_MC:x8 | N/A | N/A | boi_RP:x24 |
| 3.4 | Second or without charge/Off-balance sheet credit risk total | boi_met:mi184 | xbrli:monetaryItemType | instant | N/A | boi_CL:x35 | boi_CL:x30 | boi_CS:x2 | N/A | N/A | N/A | N/A | boi_RP:x24 |
| 4.1 | Total/Total | boi_met:mi2 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | N/A | boi_CS:x2 | N/A | boi_MC:x8 | N/A | N/A | boi_RP:x24 |
| 4.2 | Total/of which: bullet and balloon | boi_met:mi2 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | N/A | boi_CS:x2 | N/A | boi_MC:x8 | boi_PI:x24 | N/A | boi_RP:x24 |
| 4.3 | Total/of which: variable interest | boi_met:mi2 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CL:x35 | N/A | boi_CS:x2 | boi_CU:x24 | boi_MC:x8 | N/A | N/A | boi_RP:x24 |
| 4.4 | Total/Off-balance sheet credit risk total | boi_met:mi184 | xbrli:monetaryItemType | instant | N/A | boi_CL:x35 | N/A | boi_CS:x2 | N/A | N/A | N/A | N/A | boi_RP:x24 |