Consolidated Balance Sheet
| Concept | As at 2023-12-31 | As at 2023-03-31 | 
|---|---|---|
| Consolidated balance sheet | ||
| Balance sheet | ||
| Assets | ||
| Non-current assets | 
                                                14,866,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                14,935,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments and other assets | 
                                                5,571,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,943,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Allowance for doubtful accounts | 
                                                -29,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -32,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                1,913,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,091,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current assets | ||
| Cash and deposits | 
                                                5,064,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,568,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Securities | 
                                                15,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Accounts receivable - trade | 
                                                1,256,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,232,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Inventories | 
                                                425,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                275,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                504,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                516,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current assets | 
                                                7,265,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,593,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current assets | ||
| Property, plant and equipment | ||
| Buildings, net | 
                                                5,815,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,669,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Own-used assets | ||
| Other | — | — | 
| Other, net | 
                                                3,390,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,225,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Property, plant and equipment | 
                                                9,205,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,895,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Intangible assets | 
                                                88,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                96,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Intangible assets | ||
| Investments and other assets | ||
| Assets | 
                                                22,131,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                22,528,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | ||
| Current liabilities | ||
| Short-term borrowings | 
                                                1,650,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,150,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current portion of long-term borrowings | 
                                                1,756,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,302,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Income taxes payable | 
                                                107,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                134,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Provisions | ||
| Provision for bonuses | 
                                                25,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                81,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                2,954,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,238,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Asset retirement obligations | 
                                                148,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                218,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current liabilities | 
                                                10,635,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                10,459,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current liabilities | ||
| Long-term borrowings | 
                                                2,894,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,045,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                295,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                482,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current liabilities | 
                                                4,446,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,852,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Asset retirement obligations | 
                                                1,256,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,325,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | 
                                                15,081,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                14,312,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | ||
| Shareholders' equity | 
                                                7,062,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,233,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Share capital | 
                                                100,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                100,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Capital surplus | 
                                                8,321,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                10,645,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Retained earnings | 
                                                -1,179,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -2,328,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Treasury shares | 
                                                -179,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -183,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Valuation and translation adjustments | 
                                                -12,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -17,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Valuation difference on available-for-sale securities | 
                                                -12,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -17,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                7,049,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,216,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | 
                                                22,131,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                22,528,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | ||
| Shareholders' equity | ||
| Valuation and translation adjustments |