Key Financial Data Of Reporting Company
| Concept | As at 2024-09-30 | 2024-04-01 to 2024-09-30 | 2024-04-01 to 2024-09-30 | As at 2024-09-30 | 2023-04-01 to 2024-03-31 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2023-09-30 | 2023-04-01 to 2023-09-30 | 2023-04-01 to 2023-09-30 | As at 2023-09-30 | 2022-04-01 to 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | 2022-04-01 to 2023-03-31 | As at 2022-09-30 | 2022-04-01 to 2022-09-30 | As at 2022-09-30 | 2022-04-01 to 2022-09-30 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Key financial data of reporting company | ||||||||||||||||||||
| Business results of reporting company | ||||||||||||||||||||
| Operating revenue | — | 
                                                2,554,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                5,191,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                2,764,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,692,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                2,730,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Ordinary income | — | — | 
                                                46,029,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                85,219,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                43,357,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                89,250,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                44,512,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Ordinary profit (loss) | — | 
                                                1,882,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                11,768,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,322,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                16,025,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                9,507,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,500,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,655,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                12,061,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,188,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                9,106,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Profit (loss) | — | 
                                                1,819,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                3,249,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                1,460,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,651,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                2,159,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Share capital | — | — | — | 
                                                102,999,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                102,999,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                102,999,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                102,999,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                102,999,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Total number of issued shares | — | — | — | 
                                                281,008
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | 
                                                281,008
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                281,008
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | — | 
                                                281,008
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | 
                                                281,008
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | 
| Net assets | 
                                                248,092,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                167,468,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                244,825,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                167,386,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                167,323,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                234,528,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                167,248,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                228,697,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                167,133,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                224,057,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Total assets | 
                                                6,338,725,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                168,879,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                6,442,107,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                167,603,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                167,587,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                6,416,099,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                192,478,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,219,089,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                192,279,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                6,167,261,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets per share | 
                                                873.91
                                                
                                             | — | — | — | — | — | 
                                                863.54
                                                
                                             | — | — | — | — | 
                                                827.47
                                                
                                             | — | — | 
                                                807.64
                                                
                                             | — | — | — | 
                                                790.71
                                                
                                             | — | 
| Dividend paid per share | — | 
                                                7.50
                                                
                                             | — | — | 
                                                12.50
                                                
                                             | — | — | — | — | — | 
                                                6.25
                                                
                                             | — | 
                                                10.00
                                                
                                             | — | — | — | — | 
                                                5.00
                                                
                                             | — | — | 
| Basic earnings (loss) per share | — | — | 
                                                30.14
                                                
                                             | — | — | 
                                                38.78
                                                
                                             | — | — | — | 
                                                23.83
                                                
                                             | — | — | — | — | — | 
                                                33.89
                                                
                                             | — | — | — | 
                                                25.95
                                                
                                             | 
| Diluted earnings per share | — | — | 
                                                30.05
                                                
                                             | — | — | 
                                                38.68
                                                
                                             | — | — | — | 
                                                23.77
                                                
                                             | — | — | — | — | — | 
                                                32.05
                                                
                                             | — | — | — | 
                                                23.34
                                                
                                             | 
| Equity-to-asset ratio | 
                                                0.0386
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.9907
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.0375
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.9978
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.9976
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.0361
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.8683
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.0364
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.8687
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.0359
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | — | 
                                                150,677,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                121,348,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                158,811,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -1,034,131,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -903,095,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) investing activities | — | — | 
                                                -47,298,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -145,754,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -41,382,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                165,660,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                30,507,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) financing activities | — | — | 
                                                -1,464,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -2,860,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -1,232,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -28,753,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -27,351,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Cash and cash equivalents | 
                                                889,964,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                788,049,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                931,537,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                815,323,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                812,524,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Number of employees | 
                                                2,363
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                35
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                2,326
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                23
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                14
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                2,375
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                7
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                2,397
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                7
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                2,498
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Average number of temporary employees | 
                                                1,388
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                1,347
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                1,333
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                1,333
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                1,325
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — |