Consolidated Statement Of Changes In Equity
| Concept | 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 | 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 | 2024-04-01 to 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 | As at 2025-03-31 | As at 2025-03-31 | 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 | 2024-04-01 to 2025-03-31 | 2024-04-01 to 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | 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 | 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 | 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 | 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 | 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 | 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 | 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 | 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 | 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 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | 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 | 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 | 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 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Consolidated statement of changes in equity | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Statement of changes in equity | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Net assets | 
                                                717,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -14,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,689,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                2,719,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                3,689,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,926,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                125,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                19,884,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,513,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                5,376,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                26,672,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,583,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -14,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                532,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,376,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,415,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                10,832,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                984,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                16,895,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,616,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                30,256,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                22,603,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,719,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                5,376,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                46,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                18,930,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,689,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -14,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                9,878,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,705,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                2,705,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,981,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,415,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                984,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                15,163,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,641,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,689,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,513,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -14,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                5,376,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                28,235,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                24,941,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,293,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                265,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                21,636,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                738,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,107,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                880,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,935,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                984,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                57,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,376,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,376,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,686,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                880,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                23,349,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                18,868,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,064,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,415,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,689,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -14,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -14,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,513,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -13,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,689,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                24,456,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                17,987,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                13,571,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                750,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Changes during period | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Dividends of surplus | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | 
                                                -457,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -457,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -457,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -457,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                -457,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -457,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -457,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -457,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -457,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | 
                                                -457,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -457,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -457,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -457,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -457,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Profit (loss) attributable to owners of parent | — | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                2,188,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                2,188,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,188,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                2,049,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                2,049,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,049,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Net changes in items other than shareholders' equity | — | — | — | — | 
                                                -55,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                290,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                13,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                266,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                13,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                78,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                290,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                13,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                60,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                1,824,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                208,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,824,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,185,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                1,824,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,917,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,185,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Total changes during period | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -55,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                290,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                13,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                974,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                953,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                266,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                966,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,731,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                78,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,021,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,731,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                953,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                13,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -21,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                955,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,592,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                60,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                943,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,768,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                208,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,824,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,185,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                1,824,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                943,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,917,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,592,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,778,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -12,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |