Key Financial Data Of Group
| Concept | 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 | 2019-04-01 to 2020-03-31 | As at 2020-03-31 | 2019-04-01 to 2020-03-31 | As at 2020-03-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Key financial data of group | ||||||||||||||||||||
| Business results of group | ||||||||||||||||||||
| Net sales | 
                                                186,930,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                197,431,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                179,619,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                185,961,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                161,126,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                162,929,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                156,194,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                157,712,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                167,245,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                169,229,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | 
                                                11,515,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                11,918,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                9,423,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                9,288,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,216,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,095,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                9,146,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                9,262,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                9,188,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                9,282,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) attributable to owners of parent | — | 
                                                9,087,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                6,626,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                5,778,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                6,318,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                6,399,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Comprehensive income | — | 
                                                13,894,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                7,083,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,299,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                10,369,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                4,574,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | — | — | 
                                                93,987,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                88,795,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                80,689,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                82,424,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                77,242,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                75,779,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                74,837,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                73,178,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                67,409,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                67,565,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | — | 
                                                160,553,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                151,193,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                144,312,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                148,544,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                139,099,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                136,750,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                132,210,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                129,750,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                123,049,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                123,085,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets per share | — | — | 
                                                2,187.86
                                                
                                             | 
                                                2,072.12
                                                
                                             | — | 
                                                1,884.41
                                                
                                             | 
                                                1,920.67
                                                
                                             | — | — | — | 
                                                1,801.56
                                                
                                             | 
                                                1,771.12
                                                
                                             | 
                                                1,745.92
                                                
                                             | — | — | 
                                                1,711.91
                                                
                                             | — | 
                                                1,550.86
                                                
                                             | — | 
                                                1,559.28
                                                
                                             | 
| Basic earnings (loss) per share | 
                                                205.38
                                                
                                             | 
                                                212.10
                                                
                                             | — | — | 
                                                158.26
                                                
                                             | — | — | 
                                                154.78
                                                
                                             | 
                                                137.08
                                                
                                             | 
                                                135.08
                                                
                                             | — | — | — | 
                                                144.22
                                                
                                             | 
                                                145.98
                                                
                                             | — | 
                                                144.32
                                                
                                             | — | 
                                                145.65
                                                
                                             | — | 
| Diluted earnings per share |  |  | — | — |  | — | — |  |  |  | — | — | — |  |  | — |  | — |  | — | 
| Equity-to-asset ratio | — | — | 
                                                0.584
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.587
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.559
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.554
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.554
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.554
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.564
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.564
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.546
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.549
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Rate of return on equity | 
                                                0.104
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.103
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.087
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.083
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.079
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.076
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.089
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.089
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.095
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.096
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Price-earnings ratio | 
                                                12.1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                11.7
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                7.5
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                7.7
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                7.7
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                7.8
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                10.3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                10.1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                10.1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                10.0
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | 
                                                596,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                15,941,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -11,718,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                14,241,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                12,742,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | — | 
                                                -603,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -4,729,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -873,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -718,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -636,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | — | 
                                                -2,829,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -2,218,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -3,214,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -3,487,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -3,240,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | — | — | 
                                                22,665,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                25,348,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                16,037,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                31,747,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                21,616,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Number of employees | — | — | 
                                                1,901
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,687
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1,645
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,830
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                1,727
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,578
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,644
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                1,531
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1,617
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1,507
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | — | — | 
                                                320
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                320
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                313
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                313
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                328
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                328
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                337
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                336
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                316
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                316
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |