Key Financial Data Of Group
| Concept | As at 2024-09-30 | 2024-04-01 to 2024-09-30 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | As at 2023-09-30 | 2023-04-01 to 2023-09-30 | 
|---|---|---|---|---|---|---|
| Key financial data of group | ||||||
| Business results of group | ||||||
| Operating revenue | — | 
                                                18,749,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                49,597,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                32,856,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Ordinary profit (loss) | — | 
                                                6,679,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                15,775,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                9,461,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Profit (loss) attributable to owners of parent | — | 
                                                5,396,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                9,463,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                4,407,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Comprehensive income | — | 
                                                10,172,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                14,370,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                8,707,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                82,287,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                72,416,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                66,753,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Total assets | 
                                                109,489,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                98,774,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                89,448,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Basic earnings (loss) per share | — | 
                                                179.31
                                                
                                             | 
                                                310.67
                                                
                                             | — | — | 
                                                142.99
                                                
                                             | 
| Diluted earnings per share | — |  |  | — | — |  | 
| Equity-to-asset ratio | 
                                                0.745
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.728
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.741
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | 
                                                3,403,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -25,586,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -28,270,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) investing activities | — | 
                                                -3,929,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -8,104,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -7,475,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) financing activities | — | 
                                                -273,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                12,129,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                12,058,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Cash and cash equivalents | 
                                                18,271,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                18,199,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                16,155,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — |