Statement Of Cash Flows
| Concept | 2024-01-01 to 2024-06-30 | As at 2024-06-30 | As at 2023-12-31 | 2023-01-01 to 2023-06-30 | As at 2023-06-30 | As at 2022-12-31 | 
|---|---|---|---|---|---|---|
| Statement of cash flows | ||||||
| Statement of cash flows | ||||||
| Cash flows from operating activities | ||||||
| Subtotal | 
                                                31,258,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                18,451,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Income taxes paid | 
                                                -9,955,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -5,423,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest paid | 
                                                -4,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -4,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | 
                                                22,418,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                16,119,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from operating activities | ||||||
| Cash flows from operating activities | ||||||
| Cash flows from facilities maintenance and investing activities | ||||||
| Purchase of property, plant and equipment | 
                                                -19,498,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -15,397,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Proceeds from sale of property, plant and equipment | 
                                                2,110,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                753,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Purchase of investment securities | 
                                                -5,000,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -2,000,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Other, net | 
                                                7,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                8,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from investing activities | ||||||
| Net cash provided by (used in) investing activities | 
                                                -25,166,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                4,580,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from financing activities | ||||||
| Purchase of treasury shares | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Dividends paid | 
                                                -5,584,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -5,185,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) financing activities | 
                                                -5,704,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -5,288,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Effect of exchange rate change on cash and cash equivalents | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net increase (decrease) in cash and cash equivalents | 
                                                -8,452,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                15,411,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash and cash equivalents | — | 
                                                56,788,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                65,240,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                51,774,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                36,362,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |