Shareholdings
| Concept | As at 2025-03-31 | As at 2024-03-31 | 
|---|---|---|
| Shareholdings | ||
| Reporting company | ||
| Details of deemed holdings of shares held for purposes other than pure investment | ||
| Issue | 
                                                東レ㈱
                                                
                                             | — | 
| Number of shares | 
                                                800,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                800,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
| Carrying amount | 
                                                812,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                592,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Purpose of shareholding, overview of business alliance, quantitative effects of shareholding and reason for increase in number of shares | 
                                                退職給付信託契約に基づく議決権行使の指図権
                                                
                                             | — | 
| Whether issuer of aforementioned shares holds reporting company's shares | 
                                                有
                                                
                                             | — |