Quarterly Balance Sheet
| Concept | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | As at 2022-03-31 | As at 2022-03-31 | As at 2022-03-31 | As at 2022-03-31 | As at 2022-03-31 | As at 2022-03-31 | As at 2022-03-31 | As at 2022-03-31 | As at 2022-03-31 | As at 2022-03-31 | As at 2022-03-31 | As at 2022-03-31 | As at 2022-03-31 | As at 2022-03-31 | As at 2022-03-31 | As at 2022-03-31 | As at 2022-03-31 | As at 2022-03-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Quarterly balance sheet | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Balance sheet | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Assets | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Current assets | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Cash and deposits | — | — | — | — | — | — | — | — | — | 
                                                367,667,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                201,493,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                200,793,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                448,400,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Merchandise and finished goods | — | — | — | — | — | — | — | — | — | 
                                                1,323,036,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                1,212,189,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                1,214,666,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                1,336,108,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Work in process | — | — | — | — | — | — | — | — | — | 
                                                1,171,965,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                1,171,965,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                1,126,232,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                1,126,232,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Raw materials and supplies | — | — | — | — | — | — | — | — | — | 
                                                578,497,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                496,991,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                361,215,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                437,391,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Other | — | — | — | — | — | — | — | — | — | 
                                                30,146,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                12,102,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                35,577,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                38,737,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Allowance for doubtful accounts | — | — | — | — | — | — | — | — | — | 
                                                -957,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -1,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                -905,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -862,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Current assets | — | — | — | — | — | — | — | — | — | 
                                                8,290,680,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                8,102,653,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                7,469,116,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                7,731,234,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Non-current assets | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Property, plant and equipment | — | — | — | — | — | — | — | — | — | 
                                                6,429,825,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                6,262,899,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                6,544,155,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                6,744,239,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Property, plant and equipment | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Buildings | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                5,334,131,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                5,348,242,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Accumulated depreciation | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                -2,711,526,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                -2,632,284,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Buildings, net | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                2,622,605,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                2,715,957,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Structures | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                740,430,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                737,910,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Accumulated depreciation | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                -566,964,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                -546,463,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Structures, net | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                173,465,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                191,447,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Machinery and equipment | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                11,556,974,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                11,443,625,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Accumulated depreciation | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                -10,207,812,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                -9,823,047,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Machinery and equipment, net | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                1,349,161,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                1,620,577,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Vehicles | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                46,147,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                46,147,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Accumulated depreciation | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                -45,979,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                -45,811,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Vehicles, net | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                167,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                335,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Tools, furniture and fixtures | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                778,731,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                704,271,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Accumulated depreciation | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                -611,039,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                -600,614,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Tools, furniture and fixtures, net | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                167,692,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                103,657,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Land | — | — | — | — | — | — | — | — | — | 
                                                1,860,198,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                1,860,198,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                1,860,198,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                1,860,198,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Leased assets | — | — | — | — | — | — | — | — | — | 
                                                44,662,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                44,662,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                40,887,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                40,887,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Accumulated depreciation | — | — | — | — | — | — | — | — | — | 
                                                -29,801,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -29,801,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                -26,096,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -26,096,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Leased assets, net | — | — | — | — | — | — | — | — | — | 
                                                14,861,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                14,861,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                14,791,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                14,791,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Construction in progress | — | — | — | — | — | — | — | — | — | 
                                                75,046,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                74,746,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                37,191,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                37,191,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Other | — | — | — | — | — | — | — | — | — | 
                                                834,936,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                757,895,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Accumulated depreciation | — | — | — | — | — | — | — | — | — | 
                                                -662,423,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                -650,026,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Other, net | — | — | — | — | — | — | — | — | — | 
                                                172,513,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                107,868,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Intangible assets | — | — | — | — | — | — | — | — | — | 
                                                33,199,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                33,199,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                18,468,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                18,468,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Intangible assets | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Other | — | — | — | — | — | — | — | — | — | 
                                                33,199,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                33,199,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                18,468,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                18,468,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Investments and other assets | — | — | — | — | — | — | — | — | — | 
                                                236,309,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                385,156,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                398,141,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                248,196,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Investments and other assets | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Shares of subsidiaries and associates | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                136,177,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                136,177,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Long-term loans receivable from subsidiaries and associates | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                25,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                31,250,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Long-term prepaid expenses | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                12,249,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Deferred tax assets | — | — | — | — | — | — | — | — | — | 
                                                215,748,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                203,243,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                204,020,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                219,927,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Other | — | — | — | — | — | — | — | — | — | 
                                                22,112,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                22,292,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                16,001,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                29,821,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Allowance for doubtful accounts | — | — | — | — | — | — | — | — | — | 
                                                -1,552,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -1,557,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                -1,558,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -1,552,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Non-current assets | — | — | — | — | — | — | — | — | — | 
                                                6,699,333,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                6,681,254,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                6,960,765,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                7,010,904,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Assets | — | — | — | — | — | — | — | — | — | 
                                                14,990,014,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                14,783,908,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                14,429,881,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                14,742,138,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Liabilities | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Current liabilities | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Notes and accounts payable - trade | — | — | — | — | — | — | — | — | — | 
                                                893,592,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                812,113,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Income taxes payable | — | — | — | — | — | — | — | — | — | 
                                                68,871,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                68,871,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                18,424,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                33,833,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Other | — | — | — | — | — | — | — | — | — | 
                                                120,075,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                2,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                101,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                95,925,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Current liabilities | — | — | — | — | — | — | — | — | — | 
                                                1,907,830,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                1,790,020,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                1,553,649,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                1,692,814,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Non-current liabilities | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Other | — | — | — | — | — | — | — | — | — | 
                                                1,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                1,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Non-current liabilities | — | — | — | — | — | — | — | — | — | 
                                                382,871,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                382,871,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                395,947,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                395,947,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Liabilities | — | — | — | — | — | — | — | — | — | 
                                                2,290,701,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                2,172,892,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                1,949,597,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                2,088,761,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Net assets | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Shareholders' equity | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Share capital | — | — | — | — | — | — | — | — | — | 
                                                1,557,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                1,557,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                1,557,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                1,557,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Capital surplus | — | — | — | — | — | — | — | — | — | 
                                                1,566,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                1,566,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                1,566,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                1,566,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Retained earnings | — | — | — | — | — | — | — | — | — | 
                                                9,779,296,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                9,691,657,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                9,560,634,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                9,730,516,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Treasury shares | — | — | — | — | — | — | — | — | — | 
                                                -203,641,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -203,641,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                -203,349,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -203,349,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Shareholders' equity | — | — | — | — | — | — | — | — | — | 
                                                12,698,655,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                12,611,016,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                12,480,284,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                12,650,166,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Valuation and translation adjustments | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Valuation and translation adjustments | — | — | — | — | — | — | — | — | — | 
                                                656,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                3,210,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Net assets | 
                                                12,611,016,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,566,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,566,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                700,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -203,641,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                9,691,657,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -203,641,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,566,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,557,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                12,699,312,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                12,698,655,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                656,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                200,826,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                656,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                12,611,016,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,557,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                9,779,296,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,790,831,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,557,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,557,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,659,807,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                700,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                12,650,166,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                12,480,284,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,566,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,566,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -203,349,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                12,653,377,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,566,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -203,349,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                12,480,284,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,210,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                9,730,516,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                9,560,634,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                200,826,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,210,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,566,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -203,165,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                700,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                9,286,871,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -203,165,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,557,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                12,337,929,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -9,133,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,566,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -9,133,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                12,328,796,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                200,826,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,557,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                12,206,706,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                9,418,094,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,386,045,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,566,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                12,206,706,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | — | — | — | — | — | — | — | — | — | 
                                                14,990,014,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                14,783,908,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                14,429,881,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                14,742,138,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |