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 | ||||||||||||
| Largest holding company | ||||||||||||
| Details of deemed holdings of shares held for purposes other than pure investment | ||||||||||||
| Issue | 
                                                古河電気工業株式会社
                                                
                                             | 
                                                小田急電鉄株式会社
                                                
                                             | 
                                                株式会社セブン&アイ・ホールディングス
                                                
                                             | 
                                                京浜急行電鉄株式会社
                                                
                                             | 
                                                株式会社セブン銀行
                                                
                                             | 
                                                いすゞ自動車株式会社
                                                
                                             | — | — | — | — | — | — | 
| Number of shares | 
                                                200,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                1,000,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                3,360,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                7,500,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                1,010,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                1,330,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                1,010,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                3,360,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                7,500,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | 
                                                1,000,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
| Number of shares (Not disclosed as below threshold) | — | — | — | — | — | — | — | — | — | — | 
                                                *
                                                
                                             | — | 
| Carrying amount | 
                                                986,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,478,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,267,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,100,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,036,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,852,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,075,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,412,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,217,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,076,000,000
                                                
                                                    
                                                        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 | 
                                                議決権行使に関する指図権限を保有(退職給付信託に拠出)。
                                                
                                             | 
                                                議決権行使に関する指図権限を保有(退職給付信託に拠出)。
                                                
                                             | 
                                                議決権行使に関する指図権限を保有(退職給付信託に拠出)。
                                                
                                             |  | 
                                                議決権行使に関する指図権限を保有(退職給付信託に拠出)。
                                                
                                             | 
                                                議決権行使に関する指図権限を保有(退職給付信託に拠出)。
                                                
                                             | — | — | — | — | — | — | 
| Whether issuer of aforementioned shares holds reporting company's shares | 
                                                無
                                                
                                             | 
                                                有
                                                
                                             | 
                                                無
                                                
                                             |  | 
                                                無
                                                
                                             | 
                                                無
                                                
                                             | — | — | — | — | — | — |