v3.26.1
Severance Indemnities and Pension Plans (Summary for Plans with Accumulated Benefit Obligations in Excess of Plan Assets) (Detail) - JPY (¥)
¥ in Millions
Mar. 31, 2026
Mar. 31, 2025
Domestic, Japan | Pension benefits and SIPs    
Defined benefit plan, pension plans with accumulated benefit obligations in excess of plan assets:    
Projected benefit obligations ¥ 21,544 ¥ 21,768
Accumulated benefit obligations 21,336 21,768
Fair value of plan assets 5,762 5,304
Foreign offices and subsidiaries | Pension benefits and other benefits    
Defined benefit plan, pension plans with accumulated benefit obligations in excess of plan assets:    
Projected benefit obligations 97,923 93,518
Accumulated benefit obligations 72,918 67,399
Fair value of plan assets ¥ 10,101 ¥ 8,275