Consolidated Balance Sheet
| Concept | As at 2023-12-31 | As at 2023-03-31 | 
|---|---|---|
| Consolidated balance sheet | ||
| Balance sheet | ||
| Assets | ||
| Non-current assets | ||
| Property, plant and equipment | ||
| Own-used assets | ||
| Land | 
                                                51,725,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                52,014,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                60,777,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                57,656,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Property, plant and equipment | 
                                                112,502,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                109,671,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Intangible assets | 
                                                135,613,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                137,954,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Goodwill | 
                                                108,187,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                113,125,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                27,426,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                24,829,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Intangible assets | ||
| Other intangible assets | ||
| Investments and other assets | ||
| Investment securities | 
                                                24,942,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                27,476,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                21,148,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                22,003,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Allowance for doubtful accounts | 
                                                -161,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -140,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments and other assets | 
                                                107,661,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                110,697,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current assets | 
                                                355,776,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                358,323,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current assets | ||
| Cash and deposits | 
                                                98,853,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                95,224,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Accounts receivable - trade | 
                                                63,145,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                55,470,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Supplies | 
                                                663,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                543,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                50,194,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                42,668,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Allowance for doubtful accounts | 
                                                -41,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -36,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current assets | 
                                                354,913,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                329,808,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Assets | 
                                                710,690,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                688,132,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | ||
| Non-current liabilities | ||
| Long-term borrowings | 
                                                18,400,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                18,400,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Retirement benefit liability | 
                                                385,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,898,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-current liabilities | 
                                                47,455,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                52,143,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Asset retirement obligations | 
                                                11,831,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                11,503,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                16,314,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                15,884,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current liabilities | ||
| Short-term borrowings | 
                                                976,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                995,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Income taxes payable | 
                                                9,495,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                14,285,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Provisions | ||
| Provision for bonuses | 
                                                2,852,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,235,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Asset retirement obligations | 
                                                4,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Other | 
                                                27,367,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                25,820,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Current liabilities | 
                                                157,799,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                153,270,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities | 
                                                205,255,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                205,413,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | ||
| Shareholders' equity | 
                                                497,838,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                471,937,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Share capital | 
                                                22,051,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                22,051,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Capital surplus | 
                                                206,103,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                205,977,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Retained earnings | 
                                                291,045,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                262,001,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Treasury shares | 
                                                -21,361,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -18,094,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Valuation and translation adjustments | 
                                                7,133,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                10,492,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Valuation difference on available-for-sale securities | 
                                                7,223,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                10,547,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Foreign currency translation adjustment | 
                                                -89,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -98,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Share acquisition rights | 
                                                43,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                43,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Non-controlling interests | 
                                                419,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                245,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                505,435,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                482,718,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | 
                                                710,690,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                688,132,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | ||
| Shareholders' equity | ||
| Valuation and translation adjustments | ||
| Remeasurements of defined benefit plans | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                42,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |