Shareholdings
| Concept | 
                                    
                                        As at 2022-12-31  | 
                            
                                
                                    
                                        As at 2022-12-31  | 
                            
                                
                                    
                                        As at 2022-12-31  | 
                            
                                
                                    
                                        As at 2022-12-31  | 
                            
                                
                                    
                                        As at 2022-12-31  | 
                            
                                
                                    
                                        As at 2022-12-31  | 
                            
                                
                                    
                                        As at 2022-12-31  | 
                            
                                
                                    
                                        As at 2021-12-31  | 
                            
                                
                                    
                                        As at 2021-12-31  | 
                            
                                
                                    
                                        As at 2021-12-31  | 
                            
                                
                                    
                                        As at 2021-12-31  | 
                            
                                
                                    
                                        As at 2021-12-31  | 
                            
                                
                                    
                                        As at 2021-12-31  | 
                            
                                
                                    
                                        As at 2021-12-31  | 
                            
                        
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Shareholdings | ||||||||||||||
| Reporting company | ||||||||||||||
| Details of specified investment shares held for purposes other than pure investment | ||||||||||||||
| Issue | 
                                        
                                             
                                                ㈱百十四銀行
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                ㈱みずほフィナンシャルグループ
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                ㈱池田泉州ホールディングス
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                ㈱SUMCO
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                ホソカワミクロン㈱
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                リックス㈱
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                ㈱奥村組
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | — | — | — | 
| Number of shares | 
                                        
                                             
                                                9,600
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                28,416
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                63,270
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                15,616
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                52,400
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                31,800
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                63,270
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                14,632
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                28,416
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                1,200
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                9,600
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                52,400
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                31,800
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             
                                        
                                     | 
                                
                            
| Carrying amount | 
                                        
                                             
                                                18,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                52,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                16,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                27,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                140,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                94,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                10,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                34,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                41,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                1,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                14,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                178,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                102,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             
                                        
                                     | 
                                
                            
| Whether issuer of aforementioned shares holds reporting company's shares | 
                                        
                                             
                                                有
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                有
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                有
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                無
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                有
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                無
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                有
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | — | — | — |