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 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 | 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 | 
                                                広島ガス株式会社
                                                
                                             | 
                                                SOMPOホールディングス株式会社
                                                
                                             | 
                                                株式会社ふくおかフィナンシャルグループ
                                                
                                             | 
                                                ユニ・チャーム株式会社
                                                
                                             | 
                                                広島電鉄株式会社
                                                
                                             | 
                                                株式会社ウッドワン
                                                
                                             | 
                                                株式会社エフピコ
                                                
                                             | 
                                                株式会社フジ
                                                
                                             | — | — | — | — | — | — | — | — | 
| Number of shares | 
                                                2,430,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                431,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                15,558,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                802,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                360,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                764,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                944,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                802,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                944,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                5,186,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                764,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                360,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                1,163,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                2,430,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                431,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
| Carrying amount | 
                                                831,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,697,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                18,506,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                486,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                336,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,155,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,048,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                621,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,760,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                25,070,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,106,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                378,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                11,138,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                928,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,747,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Purpose of shareholding, overview of business alliance, quantitative effects of shareholding and reason for increase in number of shares | 
                                                議決権行使に関する指図権限(退職給付信託に拠出)
                                                
                                             |  | 
                                                議決権行使に関する指図権限(退職給付信託に拠出)
                                                
                                             | 
                                                議決権行使に関する指図権限(退職給付信託に拠出) (株式数が増加した理由)株式分割により、株式数が増加しております。
                                                
                                             | 
                                                議決権行使に関する指図権限(退職給付信託に拠出)
                                                
                                             | 
                                                議決権行使に関する指図権限(退職給付信託に拠出)
                                                
                                             | 
                                                議決権行使に関する指図権限(退職給付信託に拠出)
                                                
                                             | 
                                                議決権行使に関する指図権限(退職給付信託に拠出)
                                                
                                             | — | — | — | — | — | — | — | — | 
| Whether issuer of aforementioned shares holds reporting company's shares | 
                                                有
                                                
                                             |  | 
                                                無(注)4
                                                
                                             | 
                                                有
                                                
                                             | 
                                                有
                                                
                                             | 
                                                有
                                                
                                             | 
                                                有
                                                
                                             | 
                                                有
                                                
                                             | — | — | — | — | — | — | — | — |