v3.26.1
Derivative Financial Instruments (Fair Value Information on Derivative Instruments Recorded on Consolidated Balance Sheets) (Detail) - JPY (¥)
¥ in Billions
Mar. 31, 2026
Mar. 31, 2025
Derivatives, Fair Value [Line Items]    
Total derivative assets ¥ 38,949 ¥ 20,748
Total derivative liabilities ¥ 40,347 20,995
Derivative Asset, Statement of Financial Position [Extensible Enumeration] Trading account assets  
Derivative Liability, Statement of Financial Position [Extensible Enumeration] Trading account liabilities (Notes 15, 23 and 31)  
Interest rate contracts    
Derivatives, Fair Value [Line Items]    
Total derivative assets ¥ 32,082 14,896
Total derivative liabilities 33,764 16,071
Foreign exchange contracts    
Derivatives, Fair Value [Line Items]    
Total derivative assets 6,626 5,625
Total derivative liabilities 6,543 4,908
Equity contracts    
Derivatives, Fair Value [Line Items]    
Total derivative assets 148 146
Total derivative liabilities 101 62
Commodity contracts    
Derivatives, Fair Value [Line Items]    
Total derivative assets 21 20
Total derivative liabilities 20 20
Credit derivatives    
Derivatives, Fair Value [Line Items]    
Total derivative assets 44 51
Total derivative liabilities 71 53
Other    
Derivatives, Fair Value [Line Items]    
Total derivative assets 28 10
Total derivative liabilities (152) (119)
Not designated as hedges    
Derivatives, Fair Value [Line Items]    
Total derivative assets 38,946 20,744
Total derivative liabilities 40,342 20,992
Not designated as hedges | Interest rate contracts    
Derivatives, Fair Value [Line Items]    
Total derivative assets 32,082 14,896
Total derivative liabilities 33,764 16,071
Not designated as hedges | Foreign exchange contracts    
Derivatives, Fair Value [Line Items]    
Total derivative assets 6,623 5,621
Total derivative liabilities 6,538 4,905
Not designated as hedges | Equity contracts    
Derivatives, Fair Value [Line Items]    
Total derivative assets 148 146
Total derivative liabilities 101 62
Not designated as hedges | Commodity contracts    
Derivatives, Fair Value [Line Items]    
Total derivative assets 21 20
Total derivative liabilities 20 20
Not designated as hedges | Credit derivatives    
Derivatives, Fair Value [Line Items]    
Total derivative assets 44 51
Total derivative liabilities 71 53
Not designated as hedges | Other    
Derivatives, Fair Value [Line Items]    
Total derivative assets 28 10
Total derivative liabilities (152) (119)
Designated as hedges    
Derivatives, Fair Value [Line Items]    
Total derivative assets 3 4
Total derivative liabilities 5 3
Designated as hedges | Interest rate contracts    
Derivatives, Fair Value [Line Items]    
Total derivative assets 0 0
Total derivative liabilities 0 0
Designated as hedges | Foreign exchange contracts    
Derivatives, Fair Value [Line Items]    
Total derivative assets 3 4
Total derivative liabilities 5 3
Designated as hedges | Equity contracts    
Derivatives, Fair Value [Line Items]    
Total derivative assets 0 0
Total derivative liabilities 0 0
Designated as hedges | Commodity contracts    
Derivatives, Fair Value [Line Items]    
Total derivative assets 0 0
Total derivative liabilities 0 0
Designated as hedges | Credit derivatives    
Derivatives, Fair Value [Line Items]    
Total derivative assets 0 0
Total derivative liabilities 0 0
Designated as hedges | Other    
Derivatives, Fair Value [Line Items]    
Total derivative assets 0 0
Total derivative liabilities ¥ 0 ¥ 0