Shareholdings
| Concept | 
                                    
                                        As at 2024-03-31  | 
                            
                        
|---|---|
| Shareholdings | |
| Reporting company | |
| Investment shares held for purposes other than pure investment | |
| Shares not listed | |
| Number of issues | 
                                        
                                             
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             
                                        
                                     | 
                                
                            
| Carrying amount | 
                                        
                                             
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                            
| Shares other than those not listed | |
| Number of issues | 
                                        
                                             
                                                1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             
                                        
                                     | 
                                
                            
| Carrying amount | 
                                        
                                             
                                                77,025,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     |