Shareholdings
| Concept | 
                                    
                                        As at 2025-03-31  | 
                            
                                
                                    
                                        As at 2025-03-31  | 
                            
                                
                                    
                                        As at 2025-03-31  | 
                            
                                
                                    
                                        As at 2024-03-31  | 
                            
                                
                                    
                                        As at 2024-03-31  | 
                            
                                
                                    
                                        As at 2024-03-31  | 
                            
                        
|---|---|---|---|---|---|---|
| Shareholdings | ||||||
| Largest holding company | ||||||
| Details of deemed holdings of shares held for purposes other than pure investment | ||||||
| Issue | 
                                        
                                             
                                                イオン株式会社
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                イオンフィナンシャルサービス株式会社
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                日本板硝子株式会社
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | 
| Number of shares | 
                                        
                                             
                                                580,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                231,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                40,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                580,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                231,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             
                                        
                                     | 
                                
                            
| Number of shares (Not disclosed as below threshold) | — | — | — | 
                                        
                                             
                                                *
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
| Carrying amount | 
                                        
                                             
                                                2,175,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                304,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                15,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                2,085,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                324,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                            
| Carrying amount (Not disclosed as below threshold) | — | — | — | 
                                        
                                             
                                                *
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
| Purpose of shareholding, overview of business alliance, quantitative effects of shareholding and reason for increase in number of shares | 
                                        
                                             
                                                議決権行使権限
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                議決権行使権限
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                議決権行使権限
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | 
| Whether issuer of aforementioned shares holds reporting company's shares | 
                                        
                                             
                                                有
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                有
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                無
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — |