v3.26.1
Trading Assets - Summary of Trading Assets (Detail) - JPY (¥)
¥ in Millions
Mar. 31, 2026
Mar. 31, 2025
Disclosure of financial assets [line items]    
Total trading assets ¥ 6,890,217 ¥ 6,176,613
Debt instruments [member]    
Disclosure of financial assets [line items]    
Total trading assets 6,476,194 5,511,465
Equity instruments [member]    
Disclosure of financial assets [line items]    
Total trading assets ¥ 414,023 ¥ 665,148