Key Financial Data Of Group
| Concept | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | 2024-04-01 to 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | 2024-04-01 to 2025-03-31 | As at 2025-03-31 | 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 2023-03-31 | As at 2023-03-31 | 2022-04-01 to 2023-03-31 | 2022-04-01 to 2023-03-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Key financial data of group | ||||||||||||||||
| Business results of group | ||||||||||||||||
| Operating revenue | — | — | — | 
                                                21,298,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                8,854,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                9,833,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary income | — | — | — | — | — | — | 
                                                211,734,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                184,661,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                179,860,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Ordinary profit (loss) | — | — | — | 
                                                18,925,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                38,308,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                31,191,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                7,204,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                9,037,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                29,608,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Profit (loss) attributable to owners of parent | — | — | — | — | — | — | 
                                                27,434,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                21,389,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                20,486,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Comprehensive income | — | — | — | — | — | — | 
                                                -23,301,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                60,719,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -16,957,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | — | — | — | — | — | 
                                                542,366,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                484,900,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                481,532,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                581,115,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                527,948,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                481,983,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Total assets | — | — | — | — | — | 
                                                11,045,576,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                505,428,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                481,758,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                10,763,804,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                9,849,196,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                482,138,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net assets per share | — | — | — | — | — | 
                                                3,030.68
                                                
                                             | — | 
                                                2,709.49
                                                
                                             | 
                                                2,645.12
                                                
                                             | — | 
                                                3,192.39
                                                
                                             | — | 
                                                2,872.48
                                                
                                             | 
                                                2,622.27
                                                
                                             | — | — | 
| Basic earnings (loss) per share | — | — | — | 
                                                104.67
                                                
                                             | — | — | 
                                                152.61
                                                
                                             | — | — | 
                                                117.06
                                                
                                             | — | 
                                                38.86
                                                
                                             | — | — | 
                                                49.00
                                                
                                             | 
                                                111.01
                                                
                                             | 
| Diluted earnings per share | — | — | — | 
                                                104.56
                                                
                                             | — | — | 
                                                152.46
                                                
                                             | — | — | 
                                                116.90
                                                
                                             | — | 
                                                38.81
                                                
                                             | — | — | 
                                                48.93
                                                
                                             | 
                                                110.85
                                                
                                             | 
| Equity-to-asset ratio | — | — | — | — | — | 
                                                0.0490
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.9591
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.9990
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.0539
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.0535
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.9991
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
| Rate of return on equity | — | — | — | 
                                                0.0389
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.0488
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.0385
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.0147
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.0188
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.0379
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Price-earnings ratio | — | — | — | 
                                                15.95
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                10.94
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                11.22
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                33.82
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                18.14
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                8.00
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Net cash provided by (used in) operating activities | — | — | — | — | — | — | 
                                                46,944,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                115,595,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -403,482,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) investing activities | — | — | — | — | — | — | 
                                                -265,073,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -198,394,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                164,298,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) financing activities | — | — | — | — | — | — | 
                                                4,214,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -7,930,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -7,844,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Cash and cash equivalents | — | — | — | — | — | 
                                                1,201,718,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                1,415,632,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,506,361,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Number of employees | 
                                                89
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                2,736
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                48
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                142
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                3,015
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                43
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                7
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                2,988
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                3,009
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                4
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
| Average number of temporary employees | 
                                                19
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,651
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                15
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                23
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,707
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                9
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1,681
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1,695
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — |