v3.26.1
Due to Trust Account, Short-term Borrowings and Long-term Debt (Components of Long-term Debt) (Detail) - JPY (¥)
¥ in Millions
Mar. 31, 2026
Mar. 31, 2025
Debt Instrument [Line Items]    
Obligations under finance leases ¥ 26,088 ¥ 21,460
Total 21,900,789 21,036,051
Debt issuance cost (16,440) (13,644)
Total, after debt issuance costs 21,884,349 21,022,407
MUFG:    
Debt Instrument [Line Items]    
Obligations under finance leases 9,096 726
Total 13,855,109 12,237,098
MUFG: | Unsubordinated debt    
Debt Instrument [Line Items]    
Long-term debt 8,930,907 7,623,526
MUFG: | Unsubordinated debt | Fixed Rate Bonds I    
Debt Instrument [Line Items]    
Long-term debt ¥ 7,142,220 6,419,433
MUFG: | Unsubordinated debt | Fixed Rate Bonds I | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 1.54%  
MUFG: | Unsubordinated debt | Fixed Rate Bonds I | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 5.62%  
MUFG: | Unsubordinated debt | Fixed Rate Bonds II    
Debt Instrument [Line Items]    
Long-term debt ¥ 306,275 278,616
MUFG: | Unsubordinated debt | Fixed Rate Bonds II | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 0.85%  
MUFG: | Unsubordinated debt | Fixed Rate Bonds II | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 3.56%  
MUFG: | Unsubordinated debt | Fixed Rate Bonds III    
Debt Instrument [Line Items]    
Long-term debt ¥ 28,424 30,561
MUFG: | Unsubordinated debt | Fixed Rate Bonds III | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 2.73%  
MUFG: | Unsubordinated debt | Fixed Rate Bonds III | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 4.05%  
MUFG: | Unsubordinated debt | Adjustable Rate Bonds I    
Debt Instrument [Line Items]    
Long-term debt ¥ 245,300 280,900
MUFG: | Unsubordinated debt | Adjustable Rate Bonds I | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 0.25%  
MUFG: | Unsubordinated debt | Adjustable Rate Bonds I | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 1.88%  
MUFG: | Unsubordinated debt | Adjustable Rate Bonds II    
Debt Instrument [Line Items]    
Long-term debt ¥ 669,381 324,160
MUFG: | Unsubordinated debt | Adjustable Rate Bonds II | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 0.34%  
MUFG: | Unsubordinated debt | Adjustable Rate Bonds II | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 4.64%  
MUFG: | Unsubordinated debt | Adjustable Rate Bonds III    
Debt Instrument [Line Items]    
Long-term debt ¥ 245,000 245,000
MUFG: | Unsubordinated debt | Adjustable Rate Bonds III | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 0.91%  
MUFG: | Unsubordinated debt | Adjustable Rate Bonds III | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 1.86%  
MUFG: | Unsubordinated debt | Floating Rate Bonds I    
Debt Instrument [Line Items]    
Long-term debt ¥ 294,307 44,856
MUFG: | Unsubordinated debt | Floating Rate Bonds I | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 4.69%  
MUFG: | Unsubordinated debt | Floating Rate Bonds I | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 5.15%  
MUFG: | Subordinated debt    
Debt Instrument [Line Items]    
Long-term debt ¥ 4,915,106 4,612,846
MUFG: | Subordinated debt | Fixed Rate Bonds I    
Debt Instrument [Line Items]    
Long-term debt ¥ 1,023,959 990,959
MUFG: | Subordinated debt | Fixed Rate Bonds I | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 0.37%  
MUFG: | Subordinated debt | Fixed Rate Bonds I | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 2.39%  
MUFG: | Subordinated debt | Fixed Rate Bonds II    
Debt Instrument [Line Items]    
Long-term debt ¥ 280,535 116,997
MUFG: | Subordinated debt | Fixed Rate Bonds II | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 6.35%  
MUFG: | Subordinated debt | Fixed Rate Bonds II | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 8.20%  
MUFG: | Subordinated debt | Adjustable Rate Bonds I    
Debt Instrument [Line Items]    
Long-term debt ¥ 2,227,451 2,143,532
MUFG: | Subordinated debt | Adjustable Rate Bonds I | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 0.86%  
MUFG: | Subordinated debt | Adjustable Rate Bonds I | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 2.77%  
MUFG: | Subordinated debt | Adjustable Rate Bonds II    
Debt Instrument [Line Items]    
Long-term debt ¥ 985,791 1,005,655
MUFG: | Subordinated debt | Adjustable Rate Bonds II | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 0.35%  
MUFG: | Subordinated debt | Adjustable Rate Bonds II | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 1.86%  
MUFG: | Subordinated debt | Fixed Rate Borrowings I    
Debt Instrument [Line Items]    
Long-term debt ¥ 64,000 86,000
MUFG: | Subordinated debt | Fixed Rate Borrowings I | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 0.57%  
MUFG: | Subordinated debt | Fixed Rate Borrowings I | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 0.62%  
MUFG: | Subordinated debt | Adjustable Rate Borrowings II    
Debt Instrument [Line Items]    
Long-term debt ¥ 36,000 36,000
MUFG: | Subordinated debt | Adjustable Rate Borrowings II | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 0.72%  
MUFG: | Subordinated debt | Adjustable Rate Borrowings II | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 1.28%  
MUFG: | Subordinated debt | Adjustable Rate Borrowings I    
Debt Instrument [Line Items]    
Long-term debt ¥ 297,370 233,703
MUFG: | Subordinated debt | Adjustable Rate Borrowings I | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 1.03%  
MUFG: | Subordinated debt | Adjustable Rate Borrowings I | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 3.32%  
MUFG Bank:    
Debt Instrument [Line Items]    
Obligations under finance leases ¥ 3,901 4,397
Total 4,741,871 5,780,373
MUFG Bank: | Unsubordinated debt    
Debt Instrument [Line Items]    
Long-term debt 4,325,324 5,262,653
MUFG Bank: | Unsubordinated debt | Fixed Rate Bonds I    
Debt Instrument [Line Items]    
Long-term debt ¥ 7,800 8,300
MUFG Bank: | Unsubordinated debt | Fixed Rate Bonds I | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 2.34%  
MUFG Bank: | Unsubordinated debt | Fixed Rate Bonds I | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage  
MUFG Bank: | Unsubordinated debt | Fixed Rate Bonds II    
Debt Instrument [Line Items]    
Long-term debt ¥ 1,029,378 929,501
MUFG Bank: | Unsubordinated debt | Fixed Rate Bonds II | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 0.00%  
MUFG Bank: | Unsubordinated debt | Fixed Rate Bonds II | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 4.70%  
MUFG Bank: | Unsubordinated debt | Fixed Rate Bonds III    
Debt Instrument [Line Items]    
Long-term debt ¥ 8,253 7,294
Interest rate, stated percentage 1.81%  
MUFG Bank: | Unsubordinated debt | Fixed Rate Borrowings I    
Debt Instrument [Line Items]    
Long-term debt ¥ 2,835,175 2,358,191
MUFG Bank: | Unsubordinated debt | Fixed Rate Borrowings I | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 0.01%  
MUFG Bank: | Unsubordinated debt | Fixed Rate Borrowings I | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 0.75%  
MUFG Bank: | Unsubordinated debt | Adjustable Rate Borrowings II    
Debt Instrument [Line Items]    
Long-term debt ¥ 0 1,442,400
Interest rate, stated percentage 0.50%  
MUFG Bank: | Unsubordinated debt | Fixed Rate Borrowings II    
Debt Instrument [Line Items]    
Long-term debt ¥ 66,690 41,873
MUFG Bank: | Unsubordinated debt | Fixed Rate Borrowings II | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 2.93%  
MUFG Bank: | Unsubordinated debt | Fixed Rate Borrowings II | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 3.87%  
MUFG Bank: | Unsubordinated debt | Floating Rate Borrowings I    
Debt Instrument [Line Items]    
Long-term debt ¥ 304,818 392,524
MUFG Bank: | Unsubordinated debt | Floating Rate Borrowings I | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 4.12%  
MUFG Bank: | Unsubordinated debt | Floating Rate Borrowings I | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 4.72%  
MUFG Bank: | Unsubordinated debt | Floating Rate Borrowings II    
Debt Instrument [Line Items]    
Long-term debt ¥ 70,596 80,058
MUFG Bank: | Unsubordinated debt | Floating Rate Borrowings II | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 2.32%  
MUFG Bank: | Unsubordinated debt | Floating Rate Borrowings II | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 2.66%  
MUFG Bank: | Unsubordinated debt | Floating Rate Borrowings III    
Debt Instrument [Line Items]    
Long-term debt ¥ 2,614 2,512
Interest rate, stated percentage 2.05%  
MUFG Bank: | Subordinated debt    
Debt Instrument [Line Items]    
Long-term debt ¥ 138,800 222,300
MUFG Bank: | Subordinated debt | Fixed Rate Bonds I    
Debt Instrument [Line Items]    
Long-term debt ¥ 113,800 175,800
MUFG Bank: | Subordinated debt | Fixed Rate Bonds I | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 2.21%  
MUFG Bank: | Subordinated debt | Fixed Rate Bonds I | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 2.91%  
MUFG Bank: | Subordinated debt | Fixed Rate Borrowings I    
Debt Instrument [Line Items]    
Long-term debt ¥ 0 21,500
MUFG Bank: | Subordinated debt | Fixed Rate Borrowings I | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 1.88%  
MUFG Bank: | Subordinated debt | Fixed Rate Borrowings I | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 2.24%  
MUFG Bank: | Subordinated debt | Adjustable Rate Borrowings I    
Debt Instrument [Line Items]    
Long-term debt ¥ 10,000 10,000
Interest rate, stated percentage 1.89%  
MUFG Bank: | Subordinated debt | Floating Rate Borrowings I    
Debt Instrument [Line Items]    
Long-term debt ¥ 15,000 15,000
Interest rate, stated percentage 1.46%  
MUFG Bank: | Secured debt    
Debt Instrument [Line Items]    
Long-term debt ¥ 273,846 291,023
MUFG Bank: | Secured debt | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 0.25%  
MUFG Bank: | Secured debt | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 7.25%  
Other subsidiaries:    
Debt Instrument [Line Items]    
Obligations under finance leases ¥ 13,091 16,337
Total 3,303,809 3,018,580
Other subsidiaries: | Unsubordinated debt    
Debt Instrument [Line Items]    
Long-term debt 3,022,934 2,736,617
Other subsidiaries: | Unsubordinated debt | Fixed Rate Borrowings I    
Debt Instrument [Line Items]    
Long-term debt ¥ 4,302 5,122
Other subsidiaries: | Unsubordinated debt | Fixed Rate Borrowings I | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 0.00%  
Other subsidiaries: | Unsubordinated debt | Fixed Rate Borrowings I | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 2.14%  
Other subsidiaries: | Unsubordinated debt | Floating Rate Borrowings I    
Debt Instrument [Line Items]    
Long-term debt ¥ 151,027 188,934
Other subsidiaries: | Unsubordinated debt | Floating Rate Borrowings I | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 4.79%  
Other subsidiaries: | Unsubordinated debt | Floating Rate Borrowings I | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 6.95%  
Other subsidiaries: | Unsubordinated debt | Fixed Rate Borrowings, Bonds and Notes I    
Debt Instrument [Line Items]    
Long-term debt ¥ 966,324 977,337
Other subsidiaries: | Unsubordinated debt | Fixed Rate Borrowings, Bonds and Notes I | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 0.15%  
Other subsidiaries: | Unsubordinated debt | Fixed Rate Borrowings, Bonds and Notes I | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 5.10%  
Other subsidiaries: | Unsubordinated debt | Fixed Rate Borrowings, Bonds and Notes II    
Debt Instrument [Line Items]    
Long-term debt ¥ 16,932 30,185
Other subsidiaries: | Unsubordinated debt | Fixed Rate Borrowings, Bonds and Notes II | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 1.40%  
Other subsidiaries: | Unsubordinated debt | Fixed Rate Borrowings, Bonds and Notes II | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 9.47%  
Other subsidiaries: | Unsubordinated debt | Fixed Rate Borrowings, Bonds and Notes IV    
Debt Instrument [Line Items]    
Long-term debt ¥ 544,334 317,394
Other subsidiaries: | Unsubordinated debt | Fixed Rate Borrowings, Bonds and Notes IV | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 0.00%  
Other subsidiaries: | Unsubordinated debt | Fixed Rate Borrowings, Bonds and Notes IV | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 4.00%  
Other subsidiaries: | Unsubordinated debt | Fixed Rate Borrowings, Bonds and Notes V    
Debt Instrument [Line Items]    
Long-term debt ¥ 484,764 425,945
Other subsidiaries: | Unsubordinated debt | Fixed Rate Borrowings, Bonds and Notes V | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 0.50%  
Other subsidiaries: | Unsubordinated debt | Fixed Rate Borrowings, Bonds and Notes V | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 10.00%  
Other subsidiaries: | Unsubordinated debt | Floating/Adjustable Rate Borrowings, Bonds and Notes I    
Debt Instrument [Line Items]    
Long-term debt ¥ 673,653 622,569
Other subsidiaries: | Unsubordinated debt | Floating/Adjustable Rate Borrowings, Bonds and Notes I | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 0.00%  
Other subsidiaries: | Unsubordinated debt | Floating/Adjustable Rate Borrowings, Bonds and Notes I | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 15.90%  
Other subsidiaries: | Unsubordinated debt | Floating Rate Borrowings, Bonds and Notes I    
Debt Instrument [Line Items]    
Long-term debt ¥ 159,728 169,131
Other subsidiaries: | Unsubordinated debt | Floating Rate Borrowings, Bonds and Notes I | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 4.45%  
Other subsidiaries: | Unsubordinated debt | Floating Rate Borrowings, Bonds and Notes I | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 6.12%  
Other subsidiaries: | Unsubordinated debt | Floating Rate Borrowings, Payable in Thai baht    
Debt Instrument [Line Items]    
Long-term debt ¥ 21,870 0
Other subsidiaries: | Unsubordinated debt | Floating Rate Borrowings, Payable in Thai baht | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 3.00%  
Other subsidiaries: | Unsubordinated debt | Floating Rate Borrowings, Payable in Thai baht | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 3.05%  
Other subsidiaries: | Subordinated debt    
Debt Instrument [Line Items]    
Long-term debt ¥ 267,784 265,626
Other subsidiaries: | Subordinated debt | Fixed Rate Borrowings, Bonds and Notes I    
Debt Instrument [Line Items]    
Long-term debt ¥ 10,000 30,000
Interest rate, stated percentage 2.61%  
Other subsidiaries: | Subordinated debt | Fixed Rate Borrowings, Bonds and Notes I | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage  
Other subsidiaries: | Subordinated debt | Fixed Rate Borrowings, Bonds and Notes II    
Debt Instrument [Line Items]    
Long-term debt ¥ 1,234 2,049
Other subsidiaries: | Subordinated debt | Fixed Rate Borrowings, Bonds and Notes II | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 7.50%  
Other subsidiaries: | Subordinated debt | Fixed Rate Borrowings, Bonds and Notes II | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 8.00%  
Other subsidiaries: | Subordinated debt | Fixed Rate Borrowings, Bonds and Notes III    
Debt Instrument [Line Items]    
Long-term debt ¥ 252,720 228,800
Other subsidiaries: | Subordinated debt | Fixed Rate Borrowings, Bonds and Notes III | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 3.00%  
Other subsidiaries: | Subordinated debt | Fixed Rate Borrowings, Bonds and Notes III | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 4.30%  
Other subsidiaries: | Subordinated debt | Floating Rate Borrowings Bonds And Notes II    
Debt Instrument [Line Items]    
Long-term debt ¥ 3,830 ¥ 4,777
Interest rate, stated percentage 10.86%