Severance Indemnities and Pension Plans (Narrative) (Detail)
12 Months Ended
Mar. 31, 2022
JPY (¥)
Mar. 31, 2021
JPY (¥)
Mar. 31, 2020
JPY (¥)
Defined Benefit Plan Disclosure [Line Items]      
Eligible age for lifetime annuity payments   65 years  
Special lump-sum early termination benefits charged to operations for the fiscal year ¥ 16,235,000,000 ¥ 16,716,000,000 ¥ 13,883,000,000
Pension benefits and SIPs      
Defined Benefit Plan Disclosure [Line Items]      
Number of major fund types 4    
Domestic, Japan | Pension benefits and SIPs | Other debt securities and Japanese debt securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of debt securities issued by the MUFG Group included in plan assets ¥ 625,000,000 ¥ 600,000,000  
Percentage of fair value of debt securities issued by the MUFG Group to total fair value of plan assets 0.02% 0.02%  
Domestic, Japan | Pension benefits and SIPs | Japanese marketable equity securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of common stock issued by the MUFG Group included in plan assets ¥ 4,606,000,000 ¥ 6,116,000,000  
Percentage of fair value of common stock issued by the MUFG Group to total fair value of plan assets 0.13% 0.18%