Key Financial Data Of Group
| Concept | As at 2024-03-31 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | 2023-04-01 to 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 | 2022-04-01 to 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | 2022-04-01 to 2023-03-31 | 2021-04-01 to 2022-03-31 | 2021-04-01 to 2022-03-31 | As at 2022-03-31 | As at 2022-03-31 | As at 2021-03-31 | 2020-04-01 to 2021-03-31 | 2020-04-01 to 2021-03-31 | As at 2021-03-31 | 2019-04-01 to 2020-03-31 | As at 2020-03-31 | 2019-04-01 to 2020-03-31 | As at 2020-03-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Key financial data of group | |||||||||||||||||||||||||
| Business results of group | |||||||||||||||||||||||||
| Net sales | — | — | — | 
                                                95,205,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                81,344,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                83,602,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                84,667,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                86,922,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Operating revenue | — | 
                                                6,769,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                7,514,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                7,834,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                7,798,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                7,988,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Ordinary profit (loss) | — | 
                                                3,664,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                9,627,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                4,729,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                5,913,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,175,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,761,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                5,174,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                9,479,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                5,244,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                9,326,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) attributable to owners of parent | — | — | — | 
                                                6,011,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                3,996,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                5,350,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                6,224,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                6,971,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Comprehensive income | — | — | — | 
                                                9,717,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                4,487,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                5,909,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                9,571,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                5,267,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | — | — | — | — | 
                                                91,583,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                60,802,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                58,036,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                84,213,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                81,906,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                55,605,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                79,368,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                54,669,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                71,334,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                50,653,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | — | — | — | 
                                                139,695,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                77,127,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                67,834,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                123,986,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                125,167,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                73,073,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                122,515,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                68,748,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                115,753,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                64,376,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets per share | — | — | — | — | 
                                                2,074.22
                                                
                                             | — | — | 
                                                1,393.40
                                                
                                             | — | — | 
                                                1,324.83
                                                
                                             | 
                                                1,899.79
                                                
                                             | — | — | — | 
                                                1,835.49
                                                
                                             | 
                                                1,260.87
                                                
                                             | 
                                                1,717.79
                                                
                                             | — | — | 
                                                1,203.22
                                                
                                             | — | 
                                                1,547.57
                                                
                                             | — | 
                                                1,117.45
                                                
                                             | 
| Basic earnings (loss) per share | — | 
                                                76.01
                                                
                                             | — | 
                                                137.09
                                                
                                             | — | — | — | — | — | 
                                                103.74
                                                
                                             | — | — | 
                                                90.98
                                                
                                             | 
                                                102.52
                                                
                                             | 
                                                118.10
                                                
                                             | — | — | — | 
                                                107.12
                                                
                                             | 
                                                137.09
                                                
                                             | — | 
                                                134.47
                                                
                                             | — | 
                                                153.93
                                                
                                             | — | 
| Diluted earnings per share | — |  | — |  | — | — | — | — | — |  | — | — |  |  |  | — | — | — |  |  | — |  | — |  | — | 
| Equity-to-asset ratio | — | — | — | — | 
                                                0.648
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.788
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.856
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.671
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.647
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.761
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.637
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.795
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.606
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.787
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Rate of return on equity | — | 
                                                0.0561
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.069
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                0.0802
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.049
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.0842
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.067
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.0924
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.084
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.1250
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.102
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Price-earnings ratio | — | 
                                                21.54
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                11.94
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                12.82
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                14.62
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                12.06
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                10.47
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                16.68
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                13.04
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                12.37
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                10.80
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | — | — | 
                                                11,172,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                2,140,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                10,544,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                11,673,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                5,075,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | — | — | — | 
                                                -3,479,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                -2,669,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -685,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -611,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                940,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | — | — | — | 
                                                -1,485,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                -8,961,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -3,630,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -3,647,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -3,770,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | — | — | — | — | 
                                                25,910,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                19,651,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                29,132,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                22,839,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                15,426,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Number of employees | 
                                                100
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                331
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1,723
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                252
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                72
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                100
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                968
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                101
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,755
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                1,785
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                101
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,796
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                97
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1,767
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                89
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |