Quarterly Consolidated Statement Of Cash Flows
| Concept | As at 2025-03-31 | 2024-04-01 to 2025-03-31 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | As at 2023-03-31 | 
|---|---|---|---|---|---|
| Quarterly consolidated statement of cash flows | |||||
| Statement of cash flows | |||||
| Cash flows from operating activities | |||||
| Subtotal | — | 
                                                641,535,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                964,119,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest and dividends received | — | 
                                                73,559,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                47,336,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest paid | — | 
                                                -169,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -134,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Income taxes paid | — | 
                                                -228,485,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -213,171,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | — | 
                                                486,440,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                798,150,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from investing activities | |||||
| Purchase of property, plant and equipment | — | 
                                                -212,571,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -179,761,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Purchase of investment securities | — | 
                                                -1,303,535,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,824,338,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Other, net | — | 
                                                72,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                64,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) investing activities | — | 
                                                -330,740,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -707,296,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from financing activities | |||||
| Dividends paid | — | 
                                                -95,269,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -95,040,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Dividends paid to non-controlling interests | — | 
                                                -3,047,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -3,047,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Purchase of shares of subsidiaries not resulting in change in scope of consolidation | — | 
                                                -3,640,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) financing activities | — | 
                                                -109,492,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -105,993,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net increase (decrease) in cash and cash equivalents | — | 
                                                46,208,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -15,139,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash and cash equivalents | 
                                                3,472,339,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                3,426,131,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,441,270,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |