Key Financial Data Of Group
| Concept | As at 2024-09-30 | As at 2024-09-30 | As at 2024-09-30 | As at 2024-09-30 | As at 2024-09-30 | 2023-10-01 to 2024-09-30 | As at 2024-09-30 | As at 2024-09-30 | 2023-10-01 to 2024-09-30 | As at 2024-09-30 | As at 2023-09-30 | 2022-10-01 to 2023-09-30 | As at 2023-09-30 | 2022-10-01 to 2023-09-30 | 2021-10-01 to 2022-09-30 | As at 2022-09-30 | As at 2022-09-30 | 2021-10-01 to 2022-09-30 | As at 2021-09-30 | 2020-10-01 to 2021-09-30 | As at 2021-09-30 | 2020-10-01 to 2021-09-30 | 2019-10-01 to 2020-09-30 | As at 2020-09-30 | As at 2020-09-30 | 2019-10-01 to 2020-09-30 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Key financial data of group | ||||||||||||||||||||||||||
| Business results of group | ||||||||||||||||||||||||||
| Net sales | — | — | — | — | — | 
                                                23,487,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                22,904,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                22,731,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                23,106,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                23,896,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Ordinary profit (loss) | — | — | — | — | — | 
                                                2,368,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                2,628,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -130,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                1,508,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                3,495,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net assets | — | — | — | — | — | — | 
                                                25,324,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                24,348,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                24,131,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                24,910,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                35,357,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Total assets | — | — | — | — | — | — | 
                                                32,301,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                33,326,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                34,644,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                34,122,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                48,729,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net assets per share | — | — | — | — | — | — | 
                                                197.45
                                                
                                             | — | — | — | 
                                                189.47
                                                
                                             | — | — | — | — | 
                                                182.46
                                                
                                             | — | — | 
                                                188.75
                                                
                                             | — | — | — | — | 
                                                268.30
                                                
                                             | — | — | 
| Basic earnings (loss) per share | — | — | — | — | — | 
                                                12.24
                                                
                                             | — | — | — | — | — | 
                                                11.88
                                                
                                             | — | — | 
                                                -2.87
                                                
                                             | — | — | — | — | 
                                                -74.30
                                                
                                             | — | — | 
                                                19.01
                                                
                                             | — | — | — | 
| Diluted earnings per share | — | — | — | — | — | 
                                                12.19
                                                
                                             | — | — | — | — | — | 
                                                11.86
                                                
                                             | — | — |  | — | — | — | — |  | — | — |  | — | — | — | 
| Equity-to-asset ratio | — | — | — | — | — | — | 
                                                0.782
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.728
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.694
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.729
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.726
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
| Rate of return on equity | — | — | — | — | — | 
                                                0.063
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                0.063
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                -0.015
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                -0.325
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.073
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
| Price-earnings ratio | — | — | — | — | — | 
                                                11.6
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                19.7
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                23.3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
| Number of employees | 
                                                847
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,758
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                649
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                808
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                669
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                103
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                20
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                664
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1,504
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                743
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,291
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                742
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1,300
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                709
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,268
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Average number of temporary employees | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                130
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                92
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                112
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                100
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                18
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                8
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                107
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                186
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                118
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                177
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                121
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                198
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                121
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                205
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Revenue | — | — | — | — | — | — | — | — | 
                                                34,466,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                36,405,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                35,730,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                35,857,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                35,402,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Profit (loss) before tax | — | — | — | — | — | — | — | — | 
                                                -7,076,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                1,518,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                1,386,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -6,857,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                2,136,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Profit (loss), attributable to owners of parent | — | — | — | — | — | — | — | — | 
                                                -8,463,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                939,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                1,180,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -5,901,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                1,162,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Comprehensive income, attributable to owners of parent | — | — | — | — | — | — | — | — | 
                                                -7,710,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                2,752,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                3,003,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -4,496,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                2,526,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Equity attributable to owners of parent | — | 
                                                24,105,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                32,456,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                30,991,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                28,413,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                33,487,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Total assets | — | 
                                                41,191,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                51,166,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                48,727,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                45,887,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                55,560,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Owners' equity per share | — | 
                                                188.33
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                253.58
                                                
                                             | — | — | — | 
                                                235.18
                                                
                                             | — | — | — | 
                                                215.61
                                                
                                             | — | — | — | 
                                                254.12
                                                
                                             | — | 
| Basic earnings (loss) per share | — | — | — | — | — | — | — | — | 
                                                -66.12
                                                
                                             | — | — | — | — | 
                                                7.31
                                                
                                             | — | — | — | 
                                                8.96
                                                
                                             | — | — | — | 
                                                -44.78
                                                
                                             | — | — | — | 
                                                8.71
                                                
                                             | 
| Diluted earnings (loss) per share | — | — | — | — | — | — | — | — |  | — | — | — | — | 
                                                7.30
                                                
                                             | — | — | — | 
                                                8.94
                                                
                                             | — | — | — |  | — | — | — |  | 
| Ratio of owners' equity to gross assets | — | 
                                                0.585
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                0.634
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.636
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.619
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.603
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Rate of return on equity | — | — | — | — | — | — | — | — | 
                                                -0.299
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.030
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.040
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                -0.191
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.035
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Price-earnings ratio | — | — | — | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                32.0
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                17.9
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                50.9
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Cash flows from (used in) operating activities | — | — | — | — | — | — | — | — | 
                                                1,671,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                6,233,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                2,697,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                1,287,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                4,884,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Cash flows from (used in) investing activities | — | — | — | — | — | — | — | — | 
                                                -718,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -1,743,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                388,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -1,068,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -1,730,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Cash flows from (used in) financing activities | — | — | — | — | — | — | — | — | 
                                                -2,977,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -5,079,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -54,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -3,291,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                3,391,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Cash and cash equivalents | — | 
                                                14,633,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                16,510,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                16,521,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                13,145,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                15,962,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — |