v3.26.1
Variable Interest Entities (Assets and Liabilities of Non-consolidated Variable Interest Entities) (Detail) - JPY (¥)
¥ in Millions
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Variable Interest Entity [Line Items]      
Total assets ¥ 425,581,652 ¥ 405,940,211 ¥ 397,820,570
Total liabilities 404,741,595 386,690,473  
Non-consolidated VIEs      
Variable Interest Entity [Line Items]      
Total assets 571,998,598 466,923,252  
Maximum exposure 44,884,368 34,767,905  
Total assets 33,203,160 25,468,114  
Trading account assets 3,155,980 2,752,320  
Investment securities 4,652,941 3,982,836  
Loans 25,066,738 18,204,747  
All other assets 327,501 528,211  
Total liabilities 340,276 260,181  
All other liabilities 340,276 260,181  
Non-consolidated VIEs | Asset-backed conduits      
Variable Interest Entity [Line Items]      
Total assets 34,688,573 31,849,272  
Maximum exposure 9,656,449 9,236,883  
Total assets 8,072,236 7,249,130  
Trading account assets 71,011 27,429  
Investment securities 2,149,099 2,221,035  
Loans 5,852,126 5,000,666  
All other assets 0 0  
Total liabilities 941 1,118  
All other liabilities 941 1,118  
Non-consolidated VIEs | Investment funds      
Variable Interest Entity [Line Items]      
Total assets 312,054,610 219,612,579  
Maximum exposure 12,881,258 7,752,891  
Total assets 8,626,932 4,707,766  
Trading account assets 254,174 189,956  
Investment securities 380,439 184,096  
Loans 7,824,583 4,099,421  
All other assets 167,736 234,293  
Total liabilities 20,056 11,684  
All other liabilities 20,056 11,684  
Non-consolidated VIEs | Special purpose entities created for structured financing      
Variable Interest Entity [Line Items]      
Total assets 101,692,424 78,811,641  
Maximum exposure 12,595,698 8,945,829  
Total assets 8,206,530 6,134,534  
Trading account assets 83,649 111,542  
Investment securities 85,771 78,102  
Loans 8,000,862 5,926,307  
All other assets 36,248 18,583  
Total liabilities 307,841 235,770  
All other liabilities 307,841 235,770  
Non-consolidated VIEs | Repackaged instruments      
Variable Interest Entity [Line Items]      
Total assets 10,564,253 8,162,093  
Maximum exposure 5,348,759 4,431,963  
Total assets 5,216,341 4,282,437  
Trading account assets 2,578,422 2,120,466  
Investment securities 1,972,939 1,439,837  
Loans 664,980 559,491  
All other assets 0 162,643  
Total liabilities 42 0  
All other liabilities 42 0  
Non-consolidated VIEs | Other      
Variable Interest Entity [Line Items]      
Total assets 112,998,738 128,487,667  
Maximum exposure 4,402,204 4,400,339  
Total assets 3,081,121 3,094,247  
Trading account assets 168,724 302,927  
Investment securities 64,693 59,766  
Loans 2,724,187 2,618,862  
All other assets 123,517 112,692  
Total liabilities 11,396 11,609  
All other liabilities ¥ 11,396 ¥ 11,609