Notes - Segment Information
| Concept | 2024-04-01 to 2025-03-31 | 2024-04-01 to 2025-03-31 | 2024-04-01 to 2025-03-31 | 2024-04-01 to 2025-03-31 | As at 2025-03-31 | 2024-04-01 to 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | 2024-04-01 to 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | 2024-04-01 to 2025-03-31 | 2024-04-01 to 2025-03-31 | 2024-04-01 to 2025-03-31 | As at 2024-03-31 | 2023-04-01 to 2024-03-31 | 2023-04-01 to 2024-03-31 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | 2023-04-01 to 2024-03-31 | 2023-04-01 to 2024-03-31 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | 2023-04-01 to 2024-03-31 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Notes - Segment information | ||||||||||||||||||||||||||||||||||||
| Segment information | ||||||||||||||||||||||||||||||||||||
| Revenue | ||||||||||||||||||||||||||||||||||||
| Revenue from external customers | 
                                                295,363,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                23,356,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                74,136,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                201,963,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                715,285,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                4,015,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                715,285,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                116,452,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,298,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                279,737,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                717,245,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                85,937,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                107,889,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                219,379,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                21,005,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                717,245,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Intersegment revenue | 
                                                2,140,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                340,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,319,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                185,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                97,006,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                108,147,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                156,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -108,147,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                86,126,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,301,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -96,909,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                8,038,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                250,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                159,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                34,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                96,909,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Revenue | 
                                                297,503,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                23,696,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                82,456,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                202,148,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                715,285,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                101,021,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                823,432,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                116,608,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -108,147,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                89,425,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                282,038,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -96,909,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                717,245,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                93,975,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                108,139,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                219,538,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                21,039,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                814,154,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Share of profit (loss) of investments accounted for using equity method | — | — | — | — | — | 
                                                3,146,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                2,467,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | 
| Profit (loss) before tax | — | — | — | — | — | 
                                                4,533,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                42,669,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | 
| Assets | — | — | — | — | 
                                                1,110,514,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                719,752,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                390,762,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                43,660,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                77,447,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                133,808,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                133,003,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                166,079,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                165,754,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                131,811,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                50,270,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,147,110,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                707,443,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                439,667,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                84,146,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                186,244,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                125,199,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                129,775,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Investments accounted for using equity method | — | — | — | — | 
                                                10,068,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                9,728,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | 
| Depreciation and amortization | 
                                                8,420,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,326,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,562,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,276,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                44,189,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                3,583,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                35,774,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,608,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,415,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,224,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,547,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,357,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                35,666,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                5,449,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,473,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,235,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                6,381,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                29,309,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Impairment losses | 
                                                850,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,009,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,886,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                10,816,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                9,746,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,071,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                5,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,716,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                1,632,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,069,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,716,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — |