Consolidated Statement Of Cash Flows
| Concept | As at 2023-03-31 | 2022-04-01 to 2023-03-31 | 2021-04-01 to 2022-03-31 | As at 2022-03-31 | As at 2021-03-31 | 
|---|---|---|---|---|---|
| Consolidated statement of cash flows | |||||
| Statement of cash flows | |||||
| Cash flows from operating activities | |||||
| Subtotal | — | 
                                                -3,351,387,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,252,032,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Income taxes paid | — | 
                                                -16,709,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -19,893,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | — | 
                                                -3,368,097,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,232,138,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from investing activities | |||||
| Purchase of securities | — | 
                                                -785,895,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,136,395,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Proceeds from sale of securities | — | 
                                                1,323,150,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                444,060,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Purchase of property, plant and equipment | — | 
                                                -3,640,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -3,824,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Proceeds from sale of property, plant and equipment | — | 
                                                426,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                672,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) investing activities | — | 
                                                922,430,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -358,507,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Other, net | — | 
                                                -303,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -162,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from financing activities | |||||
| Purchase of treasury shares | — | 
                                                -5,000,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -19,520,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Dividends paid | — | 
                                                -11,881,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -12,431,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) financing activities | — | 
                                                -16,669,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -31,846,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Effect of exchange rate change on cash and cash equivalents | — | 
                                                16,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -220,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net increase (decrease) in cash and cash equivalents | — | 
                                                -2,462,319,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                841,563,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash and cash equivalents | 
                                                4,802,328,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                7,264,647,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,423,084,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |