Key Financial Data Of Reporting Company
| Concept | 2023-04-01 to 2023-12-31 | As at 2023-12-31 | 2023-10-01 to 2023-12-31 | As at 2023-03-31 | 2022-04-01 to 2023-03-31 | As at 2022-12-31 | 2022-04-01 to 2022-12-31 | 2022-10-01 to 2022-12-31 | 
|---|---|---|---|---|---|---|---|---|
| Key financial data of reporting company | ||||||||
| Business results of reporting company | ||||||||
| Net sales | 
                                                9,630,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                13,389,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                10,187,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | 
                                                104,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                311,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                240,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | — | 
                                                5,213,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,952,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,862,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Total assets | — | 
                                                12,899,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                12,085,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                12,344,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Basic earnings (loss) per share | 
                                                27.49
                                                
                                             | — | 
                                                63.69
                                                
                                             | — | 
                                                61.31
                                                
                                             | — | 
                                                48.66
                                                
                                             | 
                                                41.61
                                                
                                             | 
| Diluted earnings per share |  | — | — | — |  | — |  | — | 
| Equity-to-asset ratio | — | 
                                                0.3687
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.3743
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.3600
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — |