v3.26.1
Deposits (Estimated amounts Of Uninsured Time Deposits And Certificates Of Deposit Issued By Domestic And Foreign Offices) (Detail) - JPY (¥)
¥ in Billions
Mar. 31, 2026
Mar. 31, 2025
Domestic    
Deposits From Banking Clients [Line Items]    
Domestic deposit ¥ 21,490 ¥ 21,081
Foreign    
Deposits From Banking Clients [Line Items]    
Domestic deposit 38,084 36,467
Time deposits | Domestic    
Deposits From Banking Clients [Line Items]    
Domestic deposit 19,238 18,272
Time deposits | Foreign    
Deposits From Banking Clients [Line Items]    
Domestic deposit 28,422 24,877
Certificates of deposit | Domestic    
Deposits From Banking Clients [Line Items]    
Domestic deposit 2,253 2,809
Certificates of deposit | Foreign    
Deposits From Banking Clients [Line Items]    
Domestic deposit ¥ 9,662 ¥ 11,590