Key Financial Data Of Reporting Company
| Concept | 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 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 | 2021-10-01 to 2022-03-31 | 2021-04-01 to 2022-03-31 | As at 2022-03-31 | As at 2022-03-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Key financial data of reporting company | ||||||||||||||||||
| Business results of reporting company | ||||||||||||||||||
| Operating revenue | 
                                                8,052,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                2,176,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                10,008,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,945,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Ordinary income | — | — | — | 
                                                89,576,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                90,839,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                84,743,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                84,730,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Ordinary profit (loss) | 
                                                4,956,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                12,298,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                14,461,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -962,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                7,991,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                16,046,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,551,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                19,167,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Profit (loss) | 
                                                4,386,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                -903,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                8,013,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,544,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Share capital | — | — | — | — | 
                                                10,000,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                10,000,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                10,000,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                10,000,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total number of issued shares | — | — | — | — | 
                                                23,408,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | 
                                                25,208,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | — | 
                                                26,908,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | — | — | 
                                                27,908,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
| Net assets | — | — | 
                                                220,889,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                196,740,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                197,450,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                252,954,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                237,688,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                210,274,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                264,258,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                212,672,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | — | 
                                                6,393,070,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                197,642,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                198,547,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                5,758,652,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                5,603,724,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                210,913,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                5,712,233,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                213,001,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets per share | — | — | 
                                                9,338.59
                                                
                                             | — | 
                                                8,630.42
                                                
                                             | — | 
                                                8,477.75
                                                
                                             | — | 
                                                10,533.34
                                                
                                             | — | 
                                                9,149.42
                                                
                                             | 
                                                8,342.79
                                                
                                             | — | — | — | — | 
                                                9,576.53
                                                
                                             | 
                                                7,903.67
                                                
                                             | 
| Dividend paid per share | 
                                                120.00
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                110.00
                                                
                                             | — | — | 
                                                100.00
                                                
                                             | — | 
                                                50.00
                                                
                                             | — | — | — | 
| Interim dividend paid per share | 
                                                60.00
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                55.00
                                                
                                             | — | — | 
                                                50.00
                                                
                                             | — |  | — | — | — | 
| Basic earnings (loss) per share | 
                                                191.99
                                                
                                             | — | — | 
                                                355.05
                                                
                                             | — | — | — | 
                                                378.34
                                                
                                             | — | 
                                                -37.56
                                                
                                             | — | — | 
                                                306.85
                                                
                                             | 
                                                336.06
                                                
                                             | 
                                                56.38
                                                
                                             | 
                                                340.64
                                                
                                             | — | — | 
| Diluted earnings per share | 
                                                190.88
                                                
                                             | — | — | 
                                                354.84
                                                
                                             | — | — | — | 
                                                378.23
                                                
                                             | — |  | — | — | 
                                                306.84
                                                
                                             | 
                                                336.05
                                                
                                             |  |  | — | — | 
| Equity-to-asset ratio | — | — | 
                                                0.0331
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.9954
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.9944
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.0424
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.0409
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.9969
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.0449
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.9984
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Rate of return on equity | 
                                                0.0222
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.0355
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.0382
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                -0.0044
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.0378
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.0359
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.0072
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.0350
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
| Price-earnings ratio | 
                                                30.72
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                16.53
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                13.40
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                -134.98
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                13.47
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                12.30
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                54.27
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                8.98
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
| Payout ratio | 
                                                0.6281
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                -2.9286
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.3258
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.8868
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
| Net cash provided by (used in) operating activities | — | — | — | 
                                                490,373,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                183,653,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -128,949,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                294,117,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) investing activities | — | — | — | 
                                                -412,969,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                51,406,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -117,364,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -149,137,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) financing activities | — | — | — | 
                                                -5,720,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -12,522,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -10,420,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -5,700,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash and cash equivalents | — | — | 
                                                1,642,236,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                1,570,556,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,348,008,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                1,604,721,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Number of employees | — | 
                                                43
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,967
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                127
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,924
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                111
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1,951
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1,938
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                226
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                1,927
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                306
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | — | 
                                                3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                191
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                4
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                188
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                5
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                241
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                289
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                4
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                382
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Total shareholder return | — | — | — | — | 
                                                3.0251
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                2.5798
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                2.0740
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                1.5053
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Total return on share price index | — | — | — | — | 
                                                3.0451
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                2.3722
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                1.3738
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                1.1096
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |