Shareholdings
| Concept | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | 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 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Shareholdings | ||||||||||||
| Reporting company | ||||||||||||
| Details of deemed holdings of shares held for purposes other than pure investment | ||||||||||||
| Issue | 
                                                沖電気工業株式会社
                                                
                                             | 
                                                MS&ADインシュアランスグループホールディングス株式会社
                                                
                                             | 
                                                株式会社みずほフィナンシャルグループ
                                                
                                             | 
                                                株式会社山形銀行
                                                
                                             | 
                                                株式会社三井住友フィナンシャルグループ
                                                
                                             | 
                                                東京計器株式会社
                                                
                                             | — | — | — | — | — | — | 
| Number of shares | 
                                                170,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                71,700
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                283,050
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                74,800
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                194,100
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                198,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                74,800
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                198,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | 
                                                64,700
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                170,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                23,900
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
| Carrying amount | 
                                                167,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                231,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,146,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                105,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                736,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                662,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                88,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                538,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                862,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                576,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                196,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                194,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| 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(退職給付信託)
                                                
                                             | 
                                                議決権行使権限(退職給付信託)2024年4月1日を効力発生日とし、1株につき3株の割合とする株式分割が行われたため
                                                
                                             | 
                                                議決権行使権限(退職給付信託)
                                                
                                             | 
                                                議決権行使権限(退職給付信託)
                                                
                                             | 
                                                議決権行使権限(退職給付信託)2024年10月1日を効力発生日とし、1株につき3株の割合とする株式分割が行われたため
                                                
                                             | 
                                                議決権行使権限(退職給付信託)
                                                
                                             | — | — | — | — | — | — | 
| Whether issuer of aforementioned shares holds reporting company's shares | 
                                                有
                                                
                                             | 
                                                無
                                                
                                             | 
                                                無
                                                
                                             | 
                                                有
                                                
                                             | 
                                                無
                                                
                                             | 
                                                無
                                                
                                             | — | — | — | — | — | — |