Key Financial Data Of Reporting Company
| Concept | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | 2024-04-01 to 2025-03-31 | As at 2025-03-31 | 2024-04-01 to 2025-03-31 | 2023-04-01 to 2024-03-31 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | 2022-04-01 to 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | 2022-04-01 to 2023-03-31 | 2021-04-01 to 2022-03-31 | 2021-04-01 to 2022-03-31 | As at 2022-03-31 | As at 2022-03-31 | As at 2021-03-31 | 2020-04-01 to 2021-03-31 | 2020-04-01 to 2021-03-31 | As at 2021-03-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Key financial data of reporting company | |||||||||||||||||||||||
| Business results of reporting company | |||||||||||||||||||||||
| Net sales | — | — | — | — | 
                                                89,786,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                80,316,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                72,110,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                83,762,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                73,567,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                83,978,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                67,099,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                75,497,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                64,181,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                73,119,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | — | — | — | — | 
                                                8,138,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                7,694,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,094,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,446,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                5,735,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                6,617,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,638,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,163,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                4,133,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,595,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) | — | — | — | — | — | — | 
                                                5,806,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,952,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                4,160,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                4,103,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                2,957,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Share capital | — | — | — | — | — | 
                                                5,753,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                5,753,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                5,753,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                5,753,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                5,753,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total number of issued shares | — | — | — | — | — | 
                                                23,756,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | — | 
                                                23,756,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | 
                                                25,006,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | — | — | 
                                                25,006,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | 
                                                25,006,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
| Net assets | — | — | — | 
                                                71,684,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                63,222,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                69,914,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                61,726,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                57,238,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                64,714,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                63,409,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                56,186,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                62,593,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                55,796,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | — | — | 
                                                99,915,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                91,152,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                98,226,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                87,244,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                83,965,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                94,687,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                87,466,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                78,137,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                86,138,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                76,458,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets per share | — | — | — | 
                                                3,202.02
                                                
                                             | — | 
                                                2,863.40
                                                
                                             | — | — | — | 
                                                3,056.74
                                                
                                             | 
                                                2,737.11
                                                
                                             | — | 
                                                2,487.64
                                                
                                             | 
                                                2,771.49
                                                
                                             | — | — | — | 
                                                2,635.31
                                                
                                             | 
                                                2,388.11
                                                
                                             | 
                                                2,556.56
                                                
                                             | — | — | 
                                                2,329.15
                                                
                                             | 
| Dividend paid per share | — | — | — | — | — | — | 
                                                94.00
                                                
                                             | 
                                                86.00
                                                
                                             | — | — | — | 
                                                85.00
                                                
                                             | — | — | — | 
                                                82.00
                                                
                                             | — | — | — | — | 
                                                80.00
                                                
                                             | — | — | 
| Interim dividend paid per share | — | — | — | — | — | — | 
                                                44.00
                                                
                                             | 
                                                43.00
                                                
                                             | — | — | — | 
                                                42.00
                                                
                                             | — | — | — | 
                                                40.00
                                                
                                             | — | — | — | — | 
                                                40.00
                                                
                                             | — | — | 
| Basic earnings (loss) per share | — | — | — | — | 
                                                265.06
                                                
                                             | — | 
                                                260.54
                                                
                                             | 
                                                173.76
                                                
                                             | 
                                                211.06
                                                
                                             | — | — | 
                                                179.58
                                                
                                             | — | — | 
                                                200.48
                                                
                                             | 
                                                172.69
                                                
                                             | 
                                                184.02
                                                
                                             | — | — | — | 
                                                123.93
                                                
                                             | 
                                                128.90
                                                
                                             | — | 
| Diluted earnings per share | — | — | — | — | 
                                                263.90
                                                
                                             | — | 
                                                259.40
                                                
                                             | 
                                                173.05
                                                
                                             | 
                                                210.20
                                                
                                             | — | — | 
                                                178.81
                                                
                                             | — | — | 
                                                199.62
                                                
                                             | 
                                                171.97
                                                
                                             | 
                                                183.25
                                                
                                             | — | — | — | 
                                                123.31
                                                
                                             | 
                                                128.24
                                                
                                             | — | 
| Equity-to-asset ratio | — | — | — | 
                                                0.706
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.692
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.700
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.706
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.680
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.672
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.707
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.717
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.709
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.727
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Rate of return on equity | — | — | — | — | 
                                                0.085
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.093
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.067
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.073
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.074
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.074
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.073
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.071
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.055
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.052
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Price-earnings ratio | — | — | — | — | 
                                                11.8
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                12.0
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                17.1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                14.1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                12.0
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                10.8
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                10.6
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                10.0
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                15.7
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                15.1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Payout ratio | — | — | — | — | — | — | 
                                                0.361
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.495
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.473
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.475
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.646
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | — | — | — | — | 
                                                -616,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                4,167,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                1,116,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,703,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                10,771,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | — | — | — | — | 
                                                -1,795,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                244,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -2,554,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -269,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                172,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | — | — | — | — | 
                                                -3,765,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -3,385,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -3,598,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -2,867,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -1,940,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | — | — | — | 
                                                22,778,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                28,956,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                27,929,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                32,965,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                34,399,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Number of employees | 
                                                815
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                58
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                102
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                975
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                815
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                966
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                810
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                805
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                966
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                961
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                801
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                944
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                793
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Total shareholder return | — | — | — | — | — | 
                                                1.833
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                1.707
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1.244
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                1.030
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                1.043
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Total return on share price index | — | — | — | — | — | 
                                                2.134
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                2.168
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1.534
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                1.450
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                1.421
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |