v3.25.2
Due to Trust Account, Short-term Borrowings and Long-term Debt (Components of Other Short-term Borrowings) (Detail) - JPY (¥)
¥ in Millions
Mar. 31, 2025
Mar. 31, 2024
Short-term Debt [Line Items]    
Total ¥ 24,636,926 ¥ 11,141,867
Less unamortized discount 0 0
Other short-term borrowings—net ¥ 24,636,926 ¥ 11,141,867
Weighted average interest rate on outstanding balance at end of fiscal year 1.58% 3.02%
Domestic offices:    
Short-term Debt [Line Items]    
Total ¥ 17,695,049 ¥ 4,756,732
Domestic offices: | Commercial paper    
Short-term Debt [Line Items]    
Total 1,527,544 1,319,959
Domestic offices: | Borrowings from the Bank of Japan    
Short-term Debt [Line Items]    
Total 14,995,160 2,171,660
Domestic offices: | Borrowings from other financial institutions    
Short-term Debt [Line Items]    
Total 175,267 96,645
Domestic offices: | Other    
Short-term Debt [Line Items]    
Total 997,078 1,168,468
Foreign offices:    
Short-term Debt [Line Items]    
Total 6,941,877 6,385,135
Other short-term borrowings—net 6,941,877 6,385,135
Foreign offices: | Commercial paper    
Short-term Debt [Line Items]    
Total 6,707,574 6,160,424
Foreign offices: | Borrowings from other financial institutions    
Short-term Debt [Line Items]    
Total 219,134 210,885
Foreign offices: | Short-term debentures    
Short-term Debt [Line Items]    
Total 0 101
Foreign offices: | Other    
Short-term Debt [Line Items]    
Total ¥ 15,169 ¥ 13,725