| Dec 31,
2020 | Dec 31,
2021 | Dec 31,
2022 | Dec 31,
2023 |
|---|
| Cash and deposits | - | 4,675 | 3,013 | 3,003 |
|---|
| Trade accounts receivable | - | 541 | 604 | 713 |
|---|
| Operational investment securities | - | 10,607 | 13,423 | 13,699 |
|---|
| Short-term loans receivable from subsidiaries and associates | - | - | 520 | - |
|---|
| Operational investment securities | - | 10,607 | 13,423 | 13,699 |
|---|
| Advances paid | - | 29 | 113 | 262 |
|---|
| Operating loans | - | 537 | 595 | 680 |
|---|
| Short-term loans receivable from subsidiaries and associates | - | - | 520 | - |
|---|
| Advances paid | - | 29 | 113 | 262 |
|---|
| Other | - | 412 | 574 | 394 |
|---|
| Other | - | 412 | 574 | 394 |
|---|
| Current assets | - | 16,800 | 18,843 | 18,751 |
|---|
| Current assets | - | 16,800 | 18,843 | 18,751 |
|---|
| Buildings, net | - | 73 | 176 | 169 |
|---|
| Tools, furniture and fixtures, net | - | 12 | 17 | 21 |
|---|
| Property, plant and equipment | - | 85 | 193 | 190 |
|---|
| Investment securities | - | 281 | 307 | 243 |
|---|
| Leasehold and guarantee deposits | - | 75 | 83 | 99 |
|---|
| Deferred tax assets | - | 754 | 538 | 358 |
|---|
| Other | - | 15 | 16 | 13 |
|---|
| Investments and other assets | - | 1,125 | 945 | 713 |
|---|
| Software | - | 0 | 1 | 2 |
|---|
| Intangible assets | - | 0 | 1 | 2 |
|---|
| Non-current assets | - | 1,210 | 1,140 | 904 |
|---|
| Investment securities | - | 281 | 307 | 243 |
|---|
| Leasehold and guarantee deposits | - | 75 | 83 | 99 |
|---|
| Deferred tax assets | - | 754 | 538 | 358 |
|---|
| Other | - | 15 | 16 | 13 |
|---|
| Investments and other assets | - | 1,125 | 945 | 713 |
|---|
| Non-current assets | - | 1,210 | 1,140 | 904 |
|---|
| Assets | - | 18,010 | 19,983 | 19,655 |
|---|
| Short-term borrowings | - | - | 100 | - |
|---|
| Current portion of long-term borrowings | - | 130 | 130 | - |
|---|
| Accounts payable - other | - | 369 | 38 | 51 |
|---|
| Accrued expenses | - | 240 | 401 | 479 |
|---|
| Accrued consumption taxes | - | - | 31 | 62 |
|---|
| Income taxes payable | - | 145 | 389 | 94 |
|---|
| Provision for bonuses | - | - | 34 | - |
|---|
| Other | - | 52 | 58 | 69 |
|---|
| Current liabilities | - | 936 | 1,181 | 755 |
|---|
| Long-term borrowings | - | 744 | 614 | - |
|---|
| Long-term deposits received | - | 19 | 19 | 25 |
|---|
| Provision for retirement benefits for directors (and other officers) | - | 102 | 102 | 102 |
|---|
| Non-current liabilities | - | 1,253 | 1,260 | 660 |
|---|
| Provision for directors' retirement benefits-stockBS | - | 163 | 180 | 198 |
|---|
| Employee provision for retirement benefits-stockBS | - | 13 | 20 | 28 |
|---|
| Retirement benefit liability | - | 128 | 160 | 175 |
|---|
| Long-term accounts payable - other | - | 84 | 70 | 70 |
|---|
| Long-term deposits received | - | 19 | 19 | 25 |
|---|
| Other | - | 0 | 95 | 63 |
|---|
| Non-current liabilities | - | 1,253 | 1,260 | 660 |
|---|
| Liabilities | - | 2,189 | 2,441 | 1,415 |
|---|
| Share capital | - | 4,058 | 4,064 | 4,066 |
|---|
| Capital surplus | - | 4,511 | 4,517 | 4,519 |
|---|
| Capital surplus | - | 4,511 | 4,517 | 4,519 |
|---|
| Retained earnings | - | 7,719 | 8,863 | 9,384 |
|---|
| Treasury shares | - | -713 | -1,065 | -1,592 |
|---|
| Retained earnings | - | 7,719 | 8,863 | 9,384 |
|---|
| Shareholders' equity | - | 15,575 | 16,378 | 16,378 |
|---|
| Treasury shares | - | -713 | -1,065 | -1,592 |
|---|
| Shareholders' equity | - | 15,575 | 16,378 | 16,378 |
|---|
| Valuation difference on available-for-sale securities | - | -418 | 111 | 426 |
|---|
| Valuation and translation adjustments | - | -466 | 249 | 715 |
|---|
| Foreign currency translation adjustment | - | -48 | 138 | 289 |
|---|
| Valuation and translation adjustments | - | -466 | 249 | 715 |
|---|
| Share acquisition rights | - | 0 | 0 | 0 |
|---|
| Net assets | 12,469 | 15,821 | 17,542 | 18,241 |
|---|
| Non-controlling interests | - | 713 | 914 | 1,147 |
|---|
| Net assets | 12,469 | 15,821 | 17,542 | 18,241 |
|---|
| Liabilities and net assets | - | 18,010 | 19,983 | 19,655 |
|---|