Key Financial Data Of Group
| Concept | As at 2024-12-31 | As at 2024-12-31 | As at 2024-12-31 | As at 2024-12-31 | As at 2024-12-31 | 2024-01-01 to 2024-12-31 | 2024-01-01 to 2024-12-31 | As at 2024-12-31 | As at 2024-12-31 | As at 2024-12-31 | As at 2024-12-31 | 2023-01-01 to 2023-12-31 | As at 2023-12-31 | 2023-01-01 to 2023-12-31 | As at 2023-12-31 | As at 2022-12-31 | 2022-01-01 to 2022-12-31 | As at 2022-12-31 | 2022-01-01 to 2022-12-31 | 2021-01-01 to 2021-12-31 | As at 2021-12-31 | As at 2021-12-31 | 2021-01-01 to 2021-12-31 | 2020-01-01 to 2020-12-31 | As at 2020-12-31 | 2020-01-01 to 2020-12-31 | As at 2020-12-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Key financial data of group | |||||||||||||||||||||||||||
| Business results of group | |||||||||||||||||||||||||||
| Operating revenue | — | — | — | — | — | 
                                                118,029,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                82,432,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                57,013,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                115,006,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                102,708,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | — | — | — | — | — | 
                                                104,974,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                70,010,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                46,363,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                104,789,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                93,473,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | — | — | — | — | 
                                                1,072,932,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                1,079,851,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,063,296,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,068,749,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                1,016,964,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Total assets | — | — | — | — | 
                                                1,382,500,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                1,212,335,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,271,496,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,248,088,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                1,208,485,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net assets per share | — | — | — | — | 
                                                1,997.67
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                1,989.83
                                                
                                             | — | — | 
                                                1,959.51
                                                
                                             | — | — | 
                                                1,970.44
                                                
                                             | — | — | — | 
                                                1,875.15
                                                
                                             | — | — | 
| Basic earnings (loss) per share | — | — | — | — | — | 
                                                196.52
                                                
                                             | — | — | — | — | — | — | — | 
                                                130.92
                                                
                                             | — | — | — | — | 
                                                87.37
                                                
                                             | 
                                                195.50
                                                
                                             | — | — | — | — | — | 
                                                174.03
                                                
                                             | — | 
| Diluted earnings per share | — | — | — | — | — |  | — | — | — | — | — | — | — |  | — | — | — | — |  |  | — | — | — | — | — |  | — | 
| Equity-to-asset ratio | — | — | — | — | 
                                                0.776
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                0.891
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.836
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.856
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.842
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
| Rate of return on equity | — | — | — | — | — | 
                                                0.099
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                0.066
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.044
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.102
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                0.095
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Price-earnings ratio | — | — | — | — | — | 
                                                43.8
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                40.4
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                49.3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                21.3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                25.4
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Number of employees | 
                                                604
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                2,756
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                9,166
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                183
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                183
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                33,947
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,391
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                35,338
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                21,421
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                34,388
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                151
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                33,482
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                147
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                137
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                33,226
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                111
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                33,151
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | 
                                                98
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                422
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                2,345
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                25
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                25
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                4,610
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                462
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                5,072
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,745
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                5,160
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                23
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                5,386
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                18
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                18
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                4,984
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                17
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                5,069
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Revenue | — | — | — | — | — | — | 
                                                2,329,861,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                2,018,568,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                1,737,998,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                1,498,276,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,422,826,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Profit (loss) before tax | — | — | — | — | — | — | 
                                                335,854,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                142,655,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                172,954,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                163,638,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                189,988,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Profit (loss), attributable to owners of parent | — | — | — | — | — | — | 
                                                343,120,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                121,616,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                133,906,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                125,463,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                148,137,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Comprehensive income, attributable to owners of parent | — | — | — | — | — | — | 
                                                455,504,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                222,855,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                267,980,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                212,218,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                139,321,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Equity attributable to owners of parent | — | — | — | — | — | — | — | — | — | 
                                                2,733,580,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,393,683,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,225,255,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                2,010,994,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                1,852,375,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | — | — | — | — | — | — | — | — | 
                                                3,739,251,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                3,361,244,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                3,102,638,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                2,820,915,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                2,627,807,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Owners' equity per share | — | — | — | — | — | — | — | — | — | 
                                                5,089.58
                                                
                                             | — | — | 
                                                4,410.80
                                                
                                             | — | — | 
                                                4,100.84
                                                
                                             | — | — | — | — | — | 
                                                3,707.64
                                                
                                             | — | — | — | — | 
                                                3,415.54
                                                
                                             | 
| Basic earnings (loss) per share | — | — | — | — | — | — | 
                                                633.76
                                                
                                             | — | — | — | — | 
                                                224.10
                                                
                                             | — | — | — | — | 
                                                246.80
                                                
                                             | — | — | — | — | — | 
                                                231.32
                                                
                                             | 
                                                273.15
                                                
                                             | — | — | — | 
| Diluted earnings (loss) per share | — | — | — | — | — | — |  | — | — | — | — |  | — | — | — | — | 
                                                246.78
                                                
                                             | — | — | — | — | — | 
                                                231.15
                                                
                                             | 
                                                272.35
                                                
                                             | — | — | — | 
| Ratio of owners' equity to gross assets | — | — | — | — | — | — | — | — | — | 
                                                0.731
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.712
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.717
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                0.713
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.705
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Rate of return on equity | — | — | — | — | — | — | 
                                                0.134
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.053
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.063
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                0.065
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.082
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
| Price-earnings ratio | — | — | — | — | — | — | 
                                                13.6
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                23.6
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                17.4
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                18.0
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                16.2
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
| Cash flows from (used in) operating activities | — | — | — | — | — | — | 
                                                354,638,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                283,232,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                211,848,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                228,864,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                232,839,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash flows from (used in) investing activities | — | — | — | — | — | — | 
                                                -265,793,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -190,538,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -81,575,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -95,288,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -99,863,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash flows from (used in) financing activities | — | — | — | — | — | — | 
                                                -189,367,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -60,260,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -95,474,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -95,844,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -104,932,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash and cash equivalents | — | — | — | — | — | — | — | — | — | 
                                                426,173,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                513,341,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                471,634,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                410,684,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                356,851,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |