Key Financial Data Of Reporting Company
| Concept | 2024-01-01 to 2024-06-30 | As at 2024-06-30 | 2023-01-01 to 2023-12-31 | As at 2023-12-31 | 2023-01-01 to 2023-06-30 | As at 2023-06-30 | 
|---|---|---|---|---|---|---|
| Key financial data of reporting company | ||||||
| Business results of reporting company | ||||||
| Net sales | 
                                                3,694,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                6,256,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,849,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | 
                                                553,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                562,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                309,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | — | 
                                                971,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                806,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                635,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | 
                                                2,541,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,756,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,372,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Basic earnings (loss) per share | 
                                                341.30
                                                
                                             | — | 
                                                368.95
                                                
                                             | — | 
                                                223.15
                                                
                                             | — | 
| Diluted earnings per share | 
                                                272.41
                                                
                                             | — | 
                                                298.26
                                                
                                             | — |  | — | 
| Equity-to-asset ratio | — | 
                                                0.382
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.293
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.268
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Net cash provided by (used in) operating activities | 
                                                144,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                354,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                176,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | 
                                                -38,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -135,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -49,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | 
                                                -236,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -60,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -35,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | — | 
                                                1,149,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,279,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,214,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |