Consolidated Balance Sheet
| Concept | As at 2024-03-31 | As at 2023-12-31 | 
|---|---|---|
| Consolidated balance sheet | ||
| Balance sheet | ||
| Assets | ||
| Non-current assets | ||
| Property, plant and equipment | 
                                                10,275,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                10,222,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Land | 
                                                4,787,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,787,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other, net | 
                                                5,487,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,434,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Property, plant and equipment | ||
| Own-used assets | ||
| Other | — | — | 
| Intangible assets | ||
| Goodwill | 
                                                4,431,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,266,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other intangible assets | ||
| Other | 
                                                436,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                474,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Intangible assets | 
                                                4,868,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,741,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments and other assets | ||
| Other | 
                                                11,092,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                10,682,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Allowance for doubtful accounts | 
                                                -119,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -119,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments and other assets | 
                                                10,973,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                10,563,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current assets | 
                                                26,116,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                25,526,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current assets | ||
| Cash and deposits | 
                                                13,532,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                19,654,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                1,363,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,434,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Allowance for doubtful accounts | 
                                                -662,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -624,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current assets | 
                                                59,105,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                54,387,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Assets | 
                                                85,222,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                79,914,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | ||
| Current liabilities | ||
| Short-term borrowings | 
                                                1,480,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,190,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Income taxes payable | 
                                                1,816,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,123,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Provisions | ||
| Provision for bonuses | 
                                                1,725,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,946,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                9,459,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,182,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current liabilities | 
                                                23,714,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                21,536,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Provision for bonuses for directors (and other officers) | 
                                                63,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                272,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current liabilities | ||
| Long-term borrowings | 
                                                150,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                160,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Retirement benefit liability | 
                                                837,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                867,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                1,595,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,574,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current liabilities | 
                                                3,291,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,283,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Asset retirement obligations | 
                                                273,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                268,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | 
                                                27,005,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                24,820,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | ||
| Shareholders' equity | 
                                                52,727,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                50,354,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Share capital | 
                                                3,025,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,025,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Capital surplus | 
                                                3,632,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,616,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Retained earnings | 
                                                47,010,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                44,652,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Treasury shares | 
                                                -940,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -939,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Valuation and translation adjustments | 
                                                5,268,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,532,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Valuation difference on available-for-sale securities | 
                                                1,779,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,513,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Foreign currency translation adjustment | 
                                                2,141,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,593,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-controlling interests | 
                                                219,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                206,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                58,216,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                55,093,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | 
                                                85,222,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                79,914,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | ||
| Shareholders' equity | ||
| Valuation and translation adjustments | ||
| Remeasurements of defined benefit plans | 
                                                1,347,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,425,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |