v3.26.1
Obligations under Guarantees and Other Off-balance Sheet Instruments (Contractual or Notional Amounts of Guarantees with Amount by Expiration Period) (Detail) - JPY (¥)
¥ in Billions
Mar. 31, 2026
Mar. 31, 2025
Guarantor Obligations [Line Items]    
Maximum potential / Contractual or Notional amount, Total ¥ 94,556 ¥ 86,790
Maximum potential / Contractual or Notional amount, Expiring in 1 year or less 50,570 45,910
Maximum potential / Contractual or Notional amount, Expiring in 1-5 years 26,539 23,051
Maximum potential / Contractual or Notional amount, Expiring in Over 5 years 17,447 17,829
Standby letters of credit and financial guarantees    
Guarantor Obligations [Line Items]    
Maximum potential / Contractual or Notional amount, Total 6,452 5,992
Maximum potential / Contractual or Notional amount, Expiring in 1 year or less 5,130 4,857
Maximum potential / Contractual or Notional amount, Expiring in 1-5 years 1,165 982
Maximum potential / Contractual or Notional amount, Expiring in Over 5 years 157 153
Performance guarantees    
Guarantor Obligations [Line Items]    
Maximum potential / Contractual or Notional amount, Total 5,748 4,851
Maximum potential / Contractual or Notional amount, Expiring in 1 year or less 4,362 3,480
Maximum potential / Contractual or Notional amount, Expiring in 1-5 years 1,232 1,235
Maximum potential / Contractual or Notional amount, Expiring in Over 5 years 154 136
Derivative instruments    
Guarantor Obligations [Line Items]    
Maximum potential / Contractual or Notional amount, Total 60,851 54,701
Maximum potential / Contractual or Notional amount, Expiring in 1 year or less 26,991 23,801
Maximum potential / Contractual or Notional amount, Expiring in 1-5 years 22,818 20,040
Maximum potential / Contractual or Notional amount, Expiring in Over 5 years 11,042 10,860
Liabilities of trust accounts    
Guarantor Obligations [Line Items]    
Maximum potential / Contractual or Notional amount, Total 21,496 21,236
Maximum potential / Contractual or Notional amount, Expiring in 1 year or less 14,087 13,762
Maximum potential / Contractual or Notional amount, Expiring in 1-5 years 1,315 794
Maximum potential / Contractual or Notional amount, Expiring in Over 5 years 6,094 6,680
Other    
Guarantor Obligations [Line Items]    
Maximum potential / Contractual or Notional amount, Total 9 10
Maximum potential / Contractual or Notional amount, Expiring in 1 year or less 0 10
Maximum potential / Contractual or Notional amount, Expiring in 1-5 years 9 0
Maximum potential / Contractual or Notional amount, Expiring in Over 5 years ¥ 0 ¥ 0