Statement Of Changes In Equity
| Concept | As at 2025-03-31 | As at 2025-03-31 | 2024-04-01 to 2025-03-31 | 2024-04-01 to 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | 2024-04-01 to 2025-03-31 | As at 2025-03-31 | 2024-04-01 to 2025-03-31 | As at 2025-03-31 | 2024-04-01 to 2025-03-31 | 2024-04-01 to 2025-03-31 | 2024-04-01 to 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | 2024-04-01 to 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | 2024-04-01 to 2025-03-31 | As at 2025-03-31 | 2024-04-01 to 2025-03-31 | As at 2025-03-31 | 2024-04-01 to 2025-03-31 | 2024-04-01 to 2025-03-31 | As at 2025-03-31 | 2024-04-01 to 2025-03-31 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | 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 2024-03-31 | 2023-04-01 to 2024-03-31 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | 2023-04-01 to 2024-03-31 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | 2023-04-01 to 2024-03-31 | 2023-04-01 to 2024-03-31 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | As at 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of changes in equity | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Statement of changes in equity | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Net assets | 
                                                1,185,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,363,026,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,120,727,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                16,827,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,102,715,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                103,001,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                298,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -37,524,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,366,867,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                176,822,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,543,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                176,822,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                3,543,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,177,537,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                176,822,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                176,822,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                931,498,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -33,783,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                5,911,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                376,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                5,911,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,185,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                103,001,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                16,827,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                1,183,824,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                913,486,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                103,001,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                16,827,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                739,391,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                10,196,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,022,834,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,185,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                176,822,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                536,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                176,822,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -25,123,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,012,102,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                10,196,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                757,403,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Changes during period | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Dividends of surplus | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -130,254,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -130,254,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -130,254,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -130,254,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -117,579,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -117,579,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -117,579,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -117,579,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Profit (loss) | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                319,719,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                319,719,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                319,719,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                319,719,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                292,161,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                292,161,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                292,161,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                292,161,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Disposal of treasury shares | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -236,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -236,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,983,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,983,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,219,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -487,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,588,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,588,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,075,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -487,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Net changes in items other than shareholders' equity | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -78,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -2,369,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -2,369,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -2,446,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -4,285,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -4,445,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -4,285,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -161,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Total changes during period | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -78,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                189,229,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                189,229,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -2,369,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                185,489,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -2,369,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                183,042,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -3,740,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -4,285,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                174,095,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                165,435,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                160,990,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -8,660,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -4,285,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -161,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                174,095,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — |