Consolidated Statement Of Changes In Equity
| Concept | As at 2025-03-31 | 2024-10-01 to 2025-03-31 | 2024-10-01 to 2025-03-31 | 2024-10-01 to 2025-03-31 | As at 2025-03-31 | 2024-10-01 to 2025-03-31 | 2024-10-01 to 2025-03-31 | 2024-10-01 to 2025-03-31 | 2024-10-01 to 2025-03-31 | As at 2025-03-31 | 2024-10-01 to 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2024-09-30 | As at 2024-09-30 | As at 2024-09-30 | As at 2024-09-30 | As at 2024-09-30 | As at 2024-09-30 | As at 2024-09-30 | As at 2024-09-30 | As at 2024-03-31 | 2023-10-01 to 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | 2023-10-01 to 2024-03-31 | 2023-10-01 to 2024-03-31 | 2023-10-01 to 2024-03-31 | As at 2024-03-31 | 2023-10-01 to 2024-03-31 | 2023-10-01 to 2024-03-31 | 2023-10-01 to 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | 2023-10-01 to 2024-03-31 | As at 2024-03-31 | As at 2023-09-30 | As at 2023-09-30 | As at 2023-09-30 | As at 2023-09-30 | As at 2023-09-30 | As at 2023-09-30 | As at 2023-09-30 | As at 2023-09-30 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Consolidated statement of changes in equity | ||||||||||||||||||||||||||||||||||||||||||||||||
| Statement of changes in equity | ||||||||||||||||||||||||||||||||||||||||||||||||
| Equity | 
                                                24,531,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -2,009,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                24,629,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                9,894,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                98,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                9,719,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                656,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,269,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                24,202,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,819,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -2,009,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                97,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,639,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                24,105,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                9,716,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                9,938,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                9,716,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                9,962,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                93,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                3,608,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -2,009,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                32,514,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                32,607,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                11,236,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                97,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -2,009,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                10,035,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,051,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                11,662,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                9,716,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                32,456,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                32,554,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Comprehensive income | ||||||||||||||||||||||||||||||||||||||||||||||||
| Profit (loss) | — | 
                                                1,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,723,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,725,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,723,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                119,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                119,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -3,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                115,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
| Other comprehensive income | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -3,162,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -3,162,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -3,162,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                557,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                557,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                557,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
| Comprehensive income | — | 
                                                1,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,723,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                562,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                561,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -3,162,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                557,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                676,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                119,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -3,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                672,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
| Transactions with owners | ||||||||||||||||||||||||||||||||||||||||||||||||
| Purchase of treasury shares | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
| Dividends | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -93,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -93,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -93,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -545,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -545,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -547,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
| Share-based payment transactions | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -44,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -41,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -41,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -21,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -21,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -21,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
| Total transactions with owners | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -44,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -93,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -134,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -134,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -618,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -545,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -73,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -619,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — |