Key Financial Data Of Group
| Concept | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | 2023-04-01 to 2024-03-31 | As at 2023-03-31 | 2022-04-01 to 2023-03-31 | 2021-04-01 to 2022-03-31 | As at 2022-03-31 | 2020-04-01 to 2021-03-31 | As at 2021-03-31 | As at 2020-03-31 | 2019-04-01 to 2020-03-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Key financial data of group | |||||||||||||||
| Business results of group | |||||||||||||||
| Net sales | — | — | — | — | — | — | 
                                                13,192,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                11,883,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                12,570,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                11,343,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                12,209,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Ordinary profit (loss) | — | — | — | — | — | — | 
                                                1,173,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                625,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,128,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                480,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                191,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | — | 
                                                19,897,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                19,550,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                19,341,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                18,801,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                18,519,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Total assets | — | 
                                                27,223,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                28,666,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                24,981,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                25,194,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                25,836,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets per share | — | 
                                                2,157.15
                                                
                                             | — | — | — | — | — | 
                                                2,052.78
                                                
                                             | — | — | 
                                                1,882.54
                                                
                                             | — | 
                                                1,829.91
                                                
                                             | 
                                                1,802.43
                                                
                                             | — | 
| Basic earnings (loss) per share | — | — | — | — | — | — | 
                                                61.50
                                                
                                             | — | 
                                                65.85
                                                
                                             | 
                                                73.73
                                                
                                             | — | 
                                                32.48
                                                
                                             | — | — | 
                                                -0.08
                                                
                                             | 
| Diluted earnings per share | — | — | — | — | — | — |  | — |  |  | — |  | — | — |  | 
| Equity-to-asset ratio | — | 
                                                0.7309
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                0.6820
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.7742
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.7463
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.7168
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Rate of return on equity | — | — | — | — | — | — | 
                                                0.0296
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.0344
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.0397
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.0179
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.0000
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Price-earnings ratio | — | — | — | — | — | — | 
                                                11.56
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                7.99
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                7.20
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                18.13
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Net cash provided by (used in) operating activities | — | — | — | — | — | — | 
                                                767,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -908,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,375,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,915,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -1,291,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) investing activities | — | — | — | — | — | — | 
                                                76,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -328,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -959,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                212,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -745,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) financing activities | — | — | — | — | — | — | 
                                                -2,197,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,403,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,375,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -1,374,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,826,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Cash and cash equivalents | — | 
                                                5,265,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                6,377,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                3,966,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,675,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,879,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Number of employees | 
                                                196
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                232
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                49
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                36
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                9
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                138
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                235
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                236
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                246
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                250
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — |