Key Financial Data Of Group
| Concept | As at 2024-06-30 | 2024-01-01 to 2024-06-30 | 2023-01-01 to 2023-12-31 | As at 2023-12-31 | As at 2023-06-30 | 2023-01-01 to 2023-06-30 | 
|---|---|---|---|---|---|---|
| Key financial data of group | ||||||
| Business results of group | ||||||
| Net sales | — | 
                                                4,668,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                10,989,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                4,575,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Ordinary profit (loss) | — | 
                                                2,081,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,292,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,053,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                15,832,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                15,675,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                13,934,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Total assets | 
                                                18,663,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                18,948,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                16,558,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Basic earnings (loss) per share | — | 
                                                78.22
                                                
                                             | 
                                                198.13
                                                
                                             | — | — | 
                                                76.72
                                                
                                             | 
| Diluted earnings per share | — |  |  | — | — |  | 
| Equity-to-asset ratio | 
                                                0.848
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.827
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.842
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | 
                                                2,339,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,991,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                3,069,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) investing activities | — | 
                                                -187,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -270,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -147,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) financing activities | — | 
                                                -1,333,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -2,381,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -1,807,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Cash and cash equivalents | 
                                                9,540,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                8,716,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,490,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — |