Notes - Segment Information
| Concept | As at 2023-12-31 | 2023-10-01 to 2023-12-31 | 2023-10-01 to 2023-12-31 | 2023-04-01 to 2023-12-31 | 2023-04-01 to 2023-12-31 | 2023-10-01 to 2023-12-31 | 2023-04-01 to 2023-12-31 | 2023-04-01 to 2023-12-31 | 2023-10-01 to 2023-12-31 | 2023-04-01 to 2023-12-31 | 2023-10-01 to 2023-12-31 | As at 2023-03-31 | 2022-04-01 to 2022-12-31 | 2022-10-01 to 2022-12-31 | 2022-10-01 to 2022-12-31 | 2022-04-01 to 2022-12-31 | 2022-10-01 to 2022-12-31 | 2022-04-01 to 2022-12-31 | 2022-04-01 to 2022-12-31 | 2022-10-01 to 2022-12-31 | 2022-04-01 to 2022-12-31 | 2022-10-01 to 2022-12-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Notes - Segment information | ||||||||||||||||||||||
| Segment information | ||||||||||||||||||||||
| Revenue | ||||||||||||||||||||||
| Revenue from external customers | — | 
                                                33,618,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,795,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                18,121,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                94,606,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                39,413,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                112,728,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                112,728,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                39,413,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                109,919,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                38,783,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,187,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                93,095,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                32,596,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                16,824,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                109,919,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                38,783,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Intersegment revenue | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Revenue | — | 
                                                33,618,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,795,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                18,121,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                94,606,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                39,413,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                112,728,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                112,728,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                39,413,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                109,919,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                38,783,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,187,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                93,095,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                32,596,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                16,824,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                109,919,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                38,783,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Profit (loss) before tax | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                30,973,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                9,826,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                28,422,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                9,023,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Assets | 
                                                247,830,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                237,451,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — |