Key Financial Data Of Group
| Concept | 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 | 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 | 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 | |||||||||||||||||||||||||||||
| Net sales | — | — | 
                                                10,724,901,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                22,041,238,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                21,242,751,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                10,622,396,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                22,174,025,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                12,334,733,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                10,737,744,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                19,633,003,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                18,734,268,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                9,959,563,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | — | — | 
                                                957,863,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,135,123,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                1,515,898,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,500,521,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                3,060,487,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,977,774,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,278,998,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,776,896,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,929,501,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,760,195,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) attributable to owners of parent | — | — | — | 
                                                1,313,086,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                966,355,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                2,413,428,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                1,718,835,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,205,517,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Comprehensive income | — | — | — | 
                                                1,906,020,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                1,300,884,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                2,757,736,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                2,239,671,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,093,292,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net assets | — | 
                                                17,399,187,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                23,358,976,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                22,440,482,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                17,630,081,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                22,590,311,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                17,367,559,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                16,154,794,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                20,464,724,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                15,072,220,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                18,982,235,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | 
                                                28,652,138,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                35,891,221,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                32,451,056,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                25,872,756,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                33,052,840,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                26,160,189,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                22,196,534,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                28,985,086,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                21,237,230,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                26,497,563,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets per share | — | 
                                                949.52
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                1,274.76
                                                
                                             | — | 
                                                1,224.84
                                                
                                             | — | 
                                                962.28
                                                
                                             | 
                                                1,216.32
                                                
                                             | — | 
                                                948.40
                                                
                                             | — | — | 
                                                885.42
                                                
                                             | 
                                                1,106.33
                                                
                                             | — | — | 
                                                826.30
                                                
                                             | — | 
                                                1,027.14
                                                
                                             | 
| Basic earnings (loss) per share | — | — | 
                                                40.09
                                                
                                             | 
                                                71.67
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                52.76
                                                
                                             | — | 
                                                73.24
                                                
                                             | — | — | 
                                                132.16
                                                
                                             | — | 
                                                111.15
                                                
                                             | 
                                                98.65
                                                
                                             | — | — | 
                                                94.22
                                                
                                             | 
                                                66.14
                                                
                                             | — | 
                                                98.45
                                                
                                             | — | 
| Diluted earnings per share | — | — | 
                                                40.00
                                                
                                             | 
                                                71.51
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                52.63
                                                
                                             | — | 
                                                73.06
                                                
                                             | — | — | 
                                                131.85
                                                
                                             | — | 
                                                110.90
                                                
                                             | 
                                                98.39
                                                
                                             | — | — | 
                                                93.98
                                                
                                             | 
                                                65.91
                                                
                                             | — | 
                                                98.11
                                                
                                             | — | 
| Equity-to-asset ratio | — | 
                                                0.607
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                0.651
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.692
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.681
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.674
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.664
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.728
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.696
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.710
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.707
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Rate of return on equity | — | — | 
                                                0.042
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.057
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                0.043
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.077
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.114
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.121
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.115
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.088
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.065
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.123
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Price-earnings ratio | — | — | 
                                                27.24
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                15.24
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                20.64
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                14.87
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                7.64
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                9.09
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                11.04
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                11.56
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                15.30
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                10.28
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | — | — | 
                                                2,845,638,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                1,915,190,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                1,802,252,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                1,061,091,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,587,182,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net cash provided by (used in) investing activities | — | — | — | 
                                                -3,365,524,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                -2,897,286,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -2,016,999,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -1,082,258,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -410,626,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net cash provided by (used in) financing activities | — | — | — | 
                                                1,435,194,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                -1,314,445,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                1,774,124,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -499,020,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,493,401,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash and cash equivalents | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                5,105,300,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,022,190,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                6,233,799,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                4,589,699,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                4,918,100,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Number of employees | 
                                                14
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                259
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                805
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                245
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                245
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                66
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                113
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                551
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                75
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                14
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                819
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                811
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                266
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                838
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                275
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                271
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                839
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                268
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                850
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | 
                                                7
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                99
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                179
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                92
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                92
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                15
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                24
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                99
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                41
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                7
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                186
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                177
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                102
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                184
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                110
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                103
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                167
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                101
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                164
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |