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 | 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 | — | — | — | 
                                                30,645,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                28,238,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                25,635,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                22,816,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                25,027,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Operating revenue | — | — | 
                                                7,341,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                6,666,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                6,163,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,353,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                5,589,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | — | — | 
                                                4,025,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,411,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                7,343,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,940,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                7,197,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,573,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,648,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                6,448,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,091,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,895,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) attributable to owners of parent | — | — | — | 
                                                5,993,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                5,201,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                4,990,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                4,378,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,498,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Comprehensive income | — | — | — | 
                                                6,095,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                5,299,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                4,826,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                4,441,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,351,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net assets | — | 
                                                10,714,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                24,989,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                25,726,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                13,405,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                27,700,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                16,706,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                16,168,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                25,710,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                16,054,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                23,688,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | 
                                                19,972,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                31,438,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                31,631,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                18,540,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                33,010,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                18,252,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                17,771,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                30,928,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                17,536,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                27,951,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets per share | — | 
                                                215.58
                                                
                                             | — | — | — | — | 
                                                523.49
                                                
                                             | — | — | — | 
                                                524.01
                                                
                                             | — | 
                                                266.33
                                                
                                             | 
                                                546.31
                                                
                                             | — | 
                                                323.47
                                                
                                             | — | — | 
                                                312.27
                                                
                                             | 
                                                505.52
                                                
                                             | — | — | 
                                                311.35
                                                
                                             | — | 
                                                465.60
                                                
                                             | 
| Basic earnings (loss) per share | — | — | 
                                                86.24
                                                
                                             | 
                                                128.01
                                                
                                             | — | — | — | — | — | 
                                                106.30
                                                
                                             | — | 
                                                79.75
                                                
                                             | — | — | 
                                                100.92
                                                
                                             | — | 
                                                69.42
                                                
                                             | 
                                                51.63
                                                
                                             | — | — | 
                                                88.67
                                                
                                             | 
                                                70.32
                                                
                                             | — | 
                                                58.19
                                                
                                             | — | 
| Diluted earnings per share | — | — | 
                                                85.26
                                                
                                             | 
                                                126.54
                                                
                                             | — | — | — | — | — | 
                                                105.03
                                                
                                             | — | 
                                                78.79
                                                
                                             | — | — | 
                                                99.62
                                                
                                             | — | 
                                                68.53
                                                
                                             | 
                                                51.01
                                                
                                             | — | — | 
                                                87.60
                                                
                                             | 
                                                69.52
                                                
                                             | — | 
                                                57.54
                                                
                                             | — | 
| Equity-to-asset ratio | — | 
                                                0.500
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.772
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.792
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.687
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.817
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.874
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.868
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.807
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.879
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.824
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Rate of return on equity | — | — | 
                                                0.355
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.243
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                0.200
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.272
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.192
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.219
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.165
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.182
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.153
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.187
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Price-earnings ratio | — | — | 
                                                27.7
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                18.7
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                24.1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                32.2
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                26.9
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                39.2
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                50.7
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                29.5
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                35.9
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                43.3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | — | — | 
                                                7,010,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                5,479,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                4,960,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                5,214,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,515,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net cash provided by (used in) investing activities | — | — | — | 
                                                -2,595,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -2,233,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                389,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -219,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                263,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net cash provided by (used in) financing activities | — | — | — | 
                                                -6,971,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -7,385,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -2,996,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -2,547,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -3,194,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash and cash equivalents | — | — | — | — | — | — | 
                                                10,346,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                12,894,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                17,031,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                14,675,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                12,216,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Number of employees | 
                                                136
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                136
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                318
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                136
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,535
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                989
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                92
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1,535
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                124
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,382
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                110
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                100
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,317
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                107
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1,303
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | 
                                                1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                38
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                81
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                38
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                4
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                90
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                2
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                63
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                52
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                68
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |