Key Financial Data Of Group
| Concept | 2022-04-01 to 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | 2022-04-01 to 2023-03-31 | 2021-04-01 to 2022-03-31 | 2021-04-01 to 2022-03-31 | As at 2022-03-31 | As at 2022-03-31 | As at 2021-03-31 | 2020-04-01 to 2021-03-31 | 2020-04-01 to 2021-03-31 | As at 2021-03-31 | 2019-04-01 to 2020-03-31 | As at 2020-03-31 | 2019-04-01 to 2020-03-31 | As at 2020-03-31 | As at 2019-03-31 | 2018-04-01 to 2019-03-31 | 2018-04-01 to 2019-03-31 | As at 2019-03-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Key financial data of group | ||||||||||||||||||||||
| Business results of group | ||||||||||||||||||||||
| Operating revenue | 
                                                18,040,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                29,340,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                15,030,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                15,124,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                20,074,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Ordinary income | — | — | — | — | — | 
                                                329,457,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                268,090,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                274,726,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                282,737,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                288,139,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | 
                                                15,770,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                46,631,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                27,016,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                64,992,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                12,266,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                54,108,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                12,445,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                53,179,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                17,110,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                69,533,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) attributable to owners of parent | — | — | — | — | — | 
                                                32,176,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                42,958,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                36,478,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                36,370,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                46,338,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Comprehensive income | — | — | — | — | — | 
                                                -37,554,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -7,603,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                129,347,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -20,483,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                46,335,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | — | — | 
                                                641,476,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                904,779,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                959,063,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                642,261,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                998,906,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                646,900,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                882,235,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                646,913,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                919,547,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                650,954,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | — | 
                                                731,775,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                21,387,481,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                24,125,520,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                735,936,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                22,835,169,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                743,620,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                17,804,808,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                740,609,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                17,372,575,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                776,704,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets per share | — | — | 
                                                602.58
                                                
                                             | 
                                                849.92
                                                
                                             | — | — | — | — | 
                                                888.10
                                                
                                             | 
                                                594.70
                                                
                                             | 
                                                861.05
                                                
                                             | — | — | 
                                                557.57
                                                
                                             | — | 
                                                760.78
                                                
                                             | — | 
                                                557.80
                                                
                                             | 
                                                783.67
                                                
                                             | — | — | 
                                                554.71
                                                
                                             | 
| Basic earnings (loss) per share | 
                                                14.84
                                                
                                             | — | — | — | — | 
                                                29.90
                                                
                                             | 
                                                24.70
                                                
                                             | 
                                                38.96
                                                
                                             | — | — | — | 
                                                10.91
                                                
                                             | 
                                                31.45
                                                
                                             | — | 
                                                10.94
                                                
                                             | — | 
                                                31.14
                                                
                                             | — | — | 
                                                15.05
                                                
                                             | 
                                                39.47
                                                
                                             | — | 
| Diluted earnings per share | 
                                                14.84
                                                
                                             | — | — | — | — | 
                                                29.89
                                                
                                             | 
                                                24.69
                                                
                                             | 
                                                38.95
                                                
                                             | — | — | — | 
                                                10.91
                                                
                                             | 
                                                31.43
                                                
                                             | — | 
                                                10.94
                                                
                                             | — | 
                                                31.12
                                                
                                             | — | — | 
                                                15.04
                                                
                                             | 
                                                39.45
                                                
                                             | — | 
| Equity-to-asset ratio | — | — | 
                                                0.8765
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.0422
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.0397
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.8725
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.0437
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.8697
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.0495
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.8731
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.0529
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.8377
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Rate of return on equity | 
                                                0.0248
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.0345
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.0422
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.0438
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.0195
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.0387
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.0197
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.0403
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.0272
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.0512
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Price-earnings ratio | 
                                                21.83
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                10.83
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                10.36
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                6.56
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                23.92
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                8.29
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                20.10
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                7.06
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                18.80
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                7.17
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | — | — | — | — | 
                                                -3,368,097,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,232,138,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                4,661,394,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                356,104,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                6,087,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | — | — | — | — | — | 
                                                922,430,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -358,507,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -112,389,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                176,093,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -211,514,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | — | — | — | — | — | 
                                                -16,669,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -31,846,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -42,603,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -50,146,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -54,944,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | — | — | — | 
                                                4,802,328,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                7,264,647,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                6,423,084,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                1,916,659,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,434,627,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Number of employees | — | 
                                                371
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                14
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                5,971
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                5,600
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                6,221
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                16
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                6,373
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                18
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                6,556
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                18
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                6,647
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                15
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | — | 
                                                156
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                3,050
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                2,894
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                3,286
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                3,493
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                3,622
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                3,824
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |