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 | 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 | ||||||||||||||||||||||||||||||
| Net sales | — | — | — | — | — | — | — | — | 
                                                79,932,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                88,475,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                71,426,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                62,736,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                63,445,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                57,246,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                50,297,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                57,539,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                48,375,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                42,532,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | — | — | — | — | — | — | — | — | 
                                                16,973,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                19,304,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                13,972,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                13,520,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                11,496,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                11,338,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,069,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                7,531,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,750,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,486,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) attributable to owners of parent | — | — | — | — | — | — | — | — | — | 
                                                14,526,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                10,812,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                8,350,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                5,173,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,958,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Comprehensive income | — | — | — | — | — | — | — | — | — | 
                                                17,913,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                12,721,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                9,869,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                7,810,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,729,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net assets | — | — | 
                                                61,646,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                82,333,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                70,732,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                53,610,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                60,574,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                45,173,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                37,909,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                52,536,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                32,554,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                45,777,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | — | 
                                                73,487,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                102,184,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                87,062,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                64,145,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                75,556,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                55,924,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                50,662,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                67,065,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                43,394,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                58,190,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets per share | — | — | 
                                                1,495.62
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                1,997.51
                                                
                                             | — | 
                                                1,690.78
                                                
                                             | — | 
                                                1,281.51
                                                
                                             | 
                                                1,449.62
                                                
                                             | — | 
                                                1,081.06
                                                
                                             | — | — | 
                                                909.16
                                                
                                             | 
                                                1,259.96
                                                
                                             | — | — | 
                                                780.73
                                                
                                             | — | 
                                                1,097.86
                                                
                                             | 
| Basic earnings (loss) per share | — | — | — | — | — | — | — | — | 
                                                326.89
                                                
                                             | 
                                                351.60
                                                
                                             | — | — | — | — | 
                                                258.56
                                                
                                             | — | 
                                                259.16
                                                
                                             | — | — | 
                                                200.01
                                                
                                             | — | 
                                                217.54
                                                
                                             | 
                                                151.05
                                                
                                             | — | — | 
                                                124.07
                                                
                                             | 
                                                44.41
                                                
                                             | — | 
                                                61.45
                                                
                                             | — | 
| Diluted earnings per share | — | — | — | — | — | — | — | — |  |  | — | — | — | — |  | — |  | — | — |  | — |  |  | — | — |  |  | — |  | — | 
| Equity-to-asset ratio | — | — | 
                                                0.839
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                0.806
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.812
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.836
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.802
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.808
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.748
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.783
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.750
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.787
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Rate of return on equity | — | — | — | — | — | — | — | — | 
                                                0.234
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.190
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.165
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.219
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.148
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.219
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.179
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.105
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.039
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.079
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Price-earnings ratio | — | — | — | — | — | — | — | — | 
                                                13.8
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                12.8
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                10.3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                10.3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                7.4
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                6.8
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                9.5
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                11.5
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                20.6
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                14.9
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | — | — | — | — | — | — | — | — | 
                                                17,644,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                10,027,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                9,232,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                8,660,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,554,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net cash provided by (used in) investing activities | — | — | — | — | — | — | — | — | — | 
                                                -6,734,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -5,145,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -3,865,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -3,780,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -12,334,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net cash provided by (used in) financing activities | — | — | — | — | — | — | — | — | — | 
                                                -6,022,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -2,778,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -2,044,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -1,250,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -2,112,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash and cash equivalents | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                38,384,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                32,640,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                29,948,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                25,832,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                21,417,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Number of employees | 
                                                621
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                101
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                935
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                121
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                429
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                3,736
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                554
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                92
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                4,719
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                834
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                101
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                4,820
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                4,604
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                947
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                4,448
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                945
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                966
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                4,098
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                1,052
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                4,070
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | 
                                                116
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                22
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                165
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                17
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                88
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                488
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                140
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                10
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                716
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                143
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                22
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                738
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                419
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                116
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                408
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                115
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                109
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                897
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                250
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                641
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |