v3.26.1
Commitments and Contingencies (Summary of Maximum Potential Amount of Future Payments of Certain Guarantees Classified Based on Internal Ratings) (Detail) - Performance guarantees, Guarantees on loans, Guarantees on securities and Other guarantees - JPY (¥)
¥ in Billions
Mar. 31, 2026
Mar. 31, 2025
Guarantor Obligations [Line Items]    
Maximum potential/Contractual or Notional amount ¥ 8,945 ¥ 7,721
Investment grade    
Guarantor Obligations [Line Items]    
Maximum potential/Contractual or Notional amount 6,755 5,900
Non-investment grade    
Guarantor Obligations [Line Items]    
Maximum potential/Contractual or Notional amount ¥ 2,190 ¥ 1,821