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 specified investment shares held for purposes other than pure investment | ||||||||||||
| Issue | 
                                                Hmcomm㈱
                                                
                                             | 
                                                ㈱ネットプロテクションズホールディングス
                                                
                                             | 
                                                ㈱リクルートホールディングス
                                                
                                             | 
                                                インフォメティス㈱
                                                
                                             | 
                                                エヴィクサー㈱
                                                
                                             | 
                                                第一生命ホールディングス㈱
                                                
                                             | — | — | — | — | — | — | 
| Number of shares | 
                                                20,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                102,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                1,000,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                8,880
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                65,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                12,100
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                12,100
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                1,000,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                65,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                102,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
| Carrying amount | 
                                                16,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                48,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,657,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                78,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                54,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                46,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,707,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                78,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                23,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Purpose of shareholding, overview of business alliance, quantitative effects of shareholding and reason for increase in number of shares | 
                                                (保有目的)業務提携関係維持強化のため(定量的な保有効果)※1(株式数が増加した理由)保有していた非上場株式が新規上場したため
                                                
                                             | 
                                                (保有目的)業務提携関係維持強化のため(定量的な保有効果)※1
                                                
                                             | 
                                                (保有目的)取引関係の維持強化のため(定量的な保有効果)※1
                                                
                                             | 
                                                (保有目的)業務提携関係維持強化のため(定量的な保有効果)※1(株式数が増加した理由)保有していた非上場株式が新規上場したため
                                                
                                             | 
                                                (保有目的)業務提携関係維持強化のため(定量的な保有効果)※1
                                                
                                             | 
                                                (保有目的)取引関係の維持強化のため(定量的な保有効果)※1
                                                
                                             | — | — | — | — | — | — | 
| Whether issuer of aforementioned shares holds reporting company's shares | 
                                                無
                                                
                                             | 
                                                無
                                                
                                             | 
                                                無
                                                
                                             | 
                                                無
                                                
                                             | 
                                                無
                                                
                                             | 
                                                有※2
                                                
                                             | — | — | — | — | — | — |