Quarterly Consolidated Statement Of Cash Flows
| Concept | 2023-01-01 to 2023-12-31 | As at 2023-12-31 | As at 2022-12-31 | 2022-01-01 to 2022-12-31 | As at 2021-12-31 | 
|---|---|---|---|---|---|
| Quarterly consolidated statement of cash flows | |||||
| Statement of cash flows | |||||
| Cash flows from operating activities | |||||
| Subtotal | 
                                                2,697,600,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                5,153,567,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Interest and dividends received | 
                                                41,919,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                29,965,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Interest paid | 
                                                -7,023,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -8,905,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Income taxes paid | 
                                                -2,894,270,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -984,633,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | 
                                                -160,001,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                4,219,957,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash flows from investing activities | |||||
| Purchase of property, plant and equipment | 
                                                -1,676,507,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -2,359,883,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Proceeds from sale of property, plant and equipment | 
                                                5,234,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Purchase of investment securities | 
                                                -18,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Proceeds from sale of investment securities | 
                                                5,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Loan advances | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -3,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Proceeds from collection of loans receivable | 
                                                1,485,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,396,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Other, net | 
                                                28,075,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                64,845,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | 
                                                -1,664,683,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -2,310,277,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash flows from financing activities | |||||
| Proceeds from long-term borrowings | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,000,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Repayments of long-term borrowings | 
                                                -200,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -200,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Purchase of treasury shares | 
                                                -102,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -161,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Dividends paid | 
                                                -320,874,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -249,640,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Other, net | 
                                                -9,541,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -14,744,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | 
                                                169,481,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                535,452,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Effect of exchange rate change on cash and cash equivalents | 
                                                3,595,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                3,382,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net increase (decrease) in cash and cash equivalents | 
                                                -1,651,608,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,448,516,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | — | 
                                                2,293,638,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,945,246,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,281,301,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |