Key Financial Data Of Reporting Company
| Concept | As at 2024-12-31 | As at 2024-12-31 | As at 2024-12-31 | As at 2024-12-31 | As at 2024-12-31 | As at 2024-12-31 | As at 2024-12-31 | 2024-01-01 to 2024-12-31 | As at 2024-12-31 | As at 2024-12-31 | As at 2024-12-31 | As at 2024-12-31 | As at 2024-12-31 | As at 2024-12-31 | As at 2024-12-31 | As at 2024-12-31 | As at 2024-12-31 | 2023-01-01 to 2023-12-31 | As at 2023-12-31 | As at 2022-12-31 | 2022-01-01 to 2022-12-31 | 2021-01-01 to 2021-12-31 | As at 2021-12-31 | As at 2021-12-31 | 2021-01-01 to 2021-12-31 | 2020-01-01 to 2020-12-31 | As at 2020-12-31 | 2020-01-01 to 2020-12-31 | As at 2020-12-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Key financial data of reporting company | |||||||||||||||||||||||||||||
| Business results of reporting company | |||||||||||||||||||||||||||||
| Net sales | — | — | — | — | — | — | — | 
                                                358,668,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                328,868,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                292,333,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                264,707,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                603,213,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                523,727,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                230,975,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | — | — | — | — | — | — | — | 
                                                53,716,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                49,843,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                47,925,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                38,451,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                58,318,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                36,859,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                24,785,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) | — | — | — | — | — | — | — | 
                                                46,524,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                44,771,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                42,724,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                35,654,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                23,254,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Share capital | — | — | — | 
                                                80,639,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                80,489,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                79,804,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                79,643,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                79,451,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Total number of issued shares | — | — | — | 
                                                462,055,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                92,349,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                92,086,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | 
                                                95,513,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | 
                                                95,391,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | 
| Net assets | — | — | — | 
                                                352,547,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                328,610,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                301,546,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                276,851,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                326,119,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                271,459,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                304,470,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | — | — | 
                                                649,607,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                602,674,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                549,421,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                494,785,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                700,985,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                454,853,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                621,578,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets per share | — | — | — | 
                                                762.73
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                711.14
                                                
                                             | 
                                                3,270.49
                                                
                                             | — | — | 
                                                3,003.62
                                                
                                             | 
                                                3,438.27
                                                
                                             | — | — | 
                                                2,838.32
                                                
                                             | — | 
                                                3,106.10
                                                
                                             | 
| Dividend paid per share | — | — | — | — | — | — | — | 
                                                147.00
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                229.00
                                                
                                             | — | — | 
                                                193.00
                                                
                                             | 
                                                163.00
                                                
                                             | — | — | — | — | — | 
                                                90.00
                                                
                                             | — | 
| Interim dividend paid per share | — | — | — | — | — | — | — | 
                                                115.00
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                97.50
                                                
                                             | — | — | 
                                                85.00
                                                
                                             | 
                                                50.00
                                                
                                             | — | — | — | — | — | 
                                                30.00
                                                
                                             | — | 
| Basic earnings (loss) per share | — | — | — | — | — | — | — | 
                                                100.75
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                97.09
                                                
                                             | — | — | 
                                                464.25
                                                
                                             | 
                                                378.84
                                                
                                             | — | — | 
                                                452.39
                                                
                                             | 
                                                256.85
                                                
                                             | — | 
                                                244.06
                                                
                                             | — | 
| Diluted earnings per share | — | — | — | — | — | — | — | 
                                                100.63
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                96.93
                                                
                                             | — | — | 
                                                463.17
                                                
                                             | 
                                                377.73
                                                
                                             | — | — | 
                                                451.07
                                                
                                             | 
                                                255.82
                                                
                                             | — | 
                                                243.08
                                                
                                             | — | 
| Equity-to-asset ratio | — | — | — | 
                                                0.542
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                0.545
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.548
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.558
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.451
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.595
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.477
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Rate of return on equity | — | — | — | — | — | — | — | 
                                                0.137
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                0.142
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.148
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.130
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.139
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.084
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.089
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Price-earnings ratio | — | — | — | — | — | — | — | 
                                                24.4
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                17.2
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                10.2
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                16.9
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                14.1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                13.1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                13.8
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Payout ratio | — | — | — | — | — | — | — | 
                                                0.546
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                0.472
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.416
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.430
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                0.369
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                68,549,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                64,234,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net cash provided by (used in) investing activities | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                -31,754,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -29,071,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net cash provided by (used in) financing activities | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                -25,179,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -9,628,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash and cash equivalents | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                136,488,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                120,544,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Number of employees | 
                                                1,384
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,505
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                904
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                5,109
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                2,824
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                10
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1,585
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                19,126
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                3,449
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                3,896
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,213
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                7,608
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,477
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                20,510
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                3,660
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                4,688
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                4,287
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                4,103
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                18,372
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                4,047
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                17,480
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Total shareholder return | — | — | — | 
                                                3.986
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                2.714
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1.554
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                1.998
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                1.041
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
| Total return on share price index | — | — | — | 
                                                1.825
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                1.515
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1.181
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                1.211
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                1.074
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — |