Key Financial Data Of Group
| 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 group | ||||||||
| Business results of group | ||||||||
| Net sales | 
                                                84,707,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                105,709,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                84,737,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | 
                                                7,385,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                8,342,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                7,405,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) attributable to owners of parent | 
                                                4,970,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                5,621,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,991,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Comprehensive income | 
                                                5,645,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                5,564,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,588,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | — | 
                                                82,882,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                79,704,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                78,685,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Total assets | — | 
                                                102,404,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                98,188,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                98,900,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Basic earnings (loss) per share | 
                                                145.59
                                                
                                             | — | 
                                                59.73
                                                
                                             | — | 
                                                164.34
                                                
                                             | — | 
                                                145.85
                                                
                                             | 
                                                68.83
                                                
                                             | 
| Diluted earnings per share | 
                                                143.82
                                                
                                             | — | — | — |  | — |  | — | 
| Equity-to-asset ratio | — | 
                                                0.791
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.794
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.779
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | 
                                                -1,869,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                7,121,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -1,107,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | 
                                                -1,271,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -304,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -230,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | 
                                                -2,697,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -2,860,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -2,820,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | — | 
                                                46,942,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                52,639,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                44,507,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — |