v3.25.2
Due to Trust Account, Short-term Borrowings and Long-term Debt (Components of Long-term Debt) (Detail) - JPY (¥)
¥ in Millions
Mar. 31, 2025
Mar. 31, 2024
Debt Instrument [Line Items]    
Obligations under finance leases ¥ 21,460 ¥ 26,055
Total 21,036,051 40,027,031
Debt issuance cost (13,644) (14,212)
Total, after debt issuance costs 21,022,407 40,012,819
MUFG:    
Debt Instrument [Line Items]    
Obligations under finance leases 726 377
Total 12,237,098 14,197,080
MUFG: | Unsubordinated debt    
Debt Instrument [Line Items]    
Long-term debt 7,623,526 9,898,523
MUFG: | Unsubordinated debt | Fixed Rate Bonds I    
Debt Instrument [Line Items]    
Long-term debt ¥ 6,419,433 7,672,722
MUFG: | Unsubordinated debt | Fixed Rate Bonds I | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 1.41%  
MUFG: | Unsubordinated debt | Fixed Rate Bonds I | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 5.57%  
MUFG: | Unsubordinated debt | Fixed Rate Bonds II    
Debt Instrument [Line Items]    
Long-term debt ¥ 278,616 566,150
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 ¥ 30,561 41,488
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 ¥ 280,900 545,200
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 1.47%  
MUFG: | Unsubordinated debt | Adjustable Rate Bonds II    
Debt Instrument [Line Items]    
Long-term debt ¥ 324,160 538,692
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 ¥ 44,856 249,827
MUFG: | Unsubordinated debt | Floating Rate Bonds I | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 5.79%  
MUFG: | Unsubordinated debt | Floating Rate Bonds I | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage  
MUFG: | Unsubordinated debt | Floating Rate Bonds II    
Debt Instrument [Line Items]    
Long-term debt ¥ 0 39,444
Interest rate, stated percentage 5.61%  
MUFG: | Subordinated debt    
Debt Instrument [Line Items]    
Long-term debt ¥ 4,612,846 4,298,180
MUFG: | Subordinated debt | Fixed Rate Bonds I    
Debt Instrument [Line Items]    
Long-term debt ¥ 990,959 937,805
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 2.05%  
MUFG: | Subordinated debt | Fixed Rate Bonds II    
Debt Instrument [Line Items]    
Long-term debt ¥ 116,997 117,692
Interest rate, stated percentage 8.20%  
MUFG: | Subordinated debt | Adjustable Rate Bonds I    
Debt Instrument [Line Items]    
Long-term debt ¥ 2,143,532 1,983,789
MUFG: | Subordinated debt | Adjustable Rate Bonds I | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 0.85%  
MUFG: | Subordinated debt | Adjustable Rate Bonds I | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 2.51%  
MUFG: | Subordinated debt | Adjustable Rate Bonds II    
Debt Instrument [Line Items]    
Long-term debt ¥ 1,005,655 963,219
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 1.57%  
MUFG: | Subordinated debt | Fixed Rate Borrowings I    
Debt Instrument [Line Items]    
Long-term debt ¥ 86,000 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 0.79%  
MUFG: | Subordinated debt | Adjustable Rate Borrowings II    
Debt Instrument [Line Items]    
Long-term debt ¥ 36,000 34,000
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 ¥ 233,703 175,675
MUFG: | Subordinated debt | Adjustable Rate Borrowings I | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 0.87%  
MUFG: | Subordinated debt | Adjustable Rate Borrowings I | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 2.95%  
MUFG Bank:    
Debt Instrument [Line Items]    
Obligations under finance leases ¥ 4,397 4,567
Total 5,780,373 22,781,771
MUFG Bank: | Unsubordinated debt    
Debt Instrument [Line Items]    
Long-term debt 5,262,653 22,174,623
MUFG Bank: | Unsubordinated debt | Fixed Rate Bonds I    
Debt Instrument [Line Items]    
Long-term debt ¥ 8,300 17,200
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 ¥ 929,501 1,060,184
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 ¥ 7,294 7,346
Interest rate, stated percentage 1.81%  
MUFG Bank: | Unsubordinated debt | Fixed Rate Borrowings I    
Debt Instrument [Line Items]    
Long-term debt ¥ 2,358,191 20,186,175
MUFG Bank: | Unsubordinated debt | Fixed Rate Borrowings I | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 0.00%  
MUFG Bank: | Unsubordinated debt | Fixed Rate Borrowings I | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 0.26%  
MUFG Bank: | Unsubordinated debt | Adjustable Rate Borrowings II    
Debt Instrument [Line Items]    
Long-term debt ¥ 1,442,400 0
Interest rate, stated percentage 0.50%  
MUFG Bank: | Unsubordinated debt | Adjustable Rate Borrowings I    
Debt Instrument [Line Items]    
Long-term debt ¥ 0 167,308
Interest rate, stated percentage 5.83%  
MUFG Bank: | Unsubordinated debt | Fixed Rate Borrowings II    
Debt Instrument [Line Items]    
Long-term debt ¥ 41,873 14,332
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 ¥ 392,524 628,297
MUFG Bank: | Unsubordinated debt | Floating Rate Borrowings I | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 0.88%  
MUFG Bank: | Unsubordinated debt | Floating Rate Borrowings I | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 5.41%  
MUFG Bank: | Unsubordinated debt | Floating Rate Borrowings II    
Debt Instrument [Line Items]    
Long-term debt ¥ 80,058 93,781
MUFG Bank: | Unsubordinated debt | Floating Rate Borrowings II | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 2.59%  
MUFG Bank: | Unsubordinated debt | Floating Rate Borrowings II | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 3.45%  
MUFG Bank: | Unsubordinated debt | Floating Rate Borrowings III    
Debt Instrument [Line Items]    
Long-term debt ¥ 2,512 0
Interest rate, stated percentage 2.05%  
MUFG Bank: | Subordinated debt    
Debt Instrument [Line Items]    
Long-term debt ¥ 222,300 242,500
MUFG Bank: | Subordinated debt | Fixed Rate Bonds I    
Debt Instrument [Line Items]    
Long-term debt ¥ 175,800 176,000
MUFG Bank: | Subordinated debt | Fixed Rate Bonds I | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 1.95%  
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 ¥ 21,500 41,500
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 1.53%  
MUFG Bank: | Subordinated debt | Floating Rate Borrowings I    
Debt Instrument [Line Items]    
Long-term debt ¥ 15,000 15,000
Interest rate, stated percentage 0.96%  
MUFG Bank: | Secured debt    
Debt Instrument [Line Items]    
Long-term debt ¥ 291,023 360,081
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 8.00%  
Other subsidiaries:    
Debt Instrument [Line Items]    
Obligations under finance leases ¥ 16,337 21,111
Total 3,018,580 3,048,180
Other subsidiaries: | Unsubordinated debt    
Debt Instrument [Line Items]    
Long-term debt 2,736,617 2,735,580
Other subsidiaries: | Unsubordinated debt | Fixed Rate Borrowings I    
Debt Instrument [Line Items]    
Long-term debt ¥ 5,122 1,004
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 0.07%  
Other subsidiaries: | Unsubordinated debt | Floating Rate Borrowings I    
Debt Instrument [Line Items]    
Long-term debt ¥ 188,934 64,086
Other subsidiaries: | Unsubordinated debt | Floating Rate Borrowings I | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 6.05%  
Other subsidiaries: | Unsubordinated debt | Floating Rate Borrowings I | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 8.00%  
Other subsidiaries: | Unsubordinated debt | Fixed Rate Borrowings, Bonds and Notes I    
Debt Instrument [Line Items]    
Long-term debt ¥ 977,337 1,051,354
Other subsidiaries: | Unsubordinated debt | Fixed Rate Borrowings, Bonds and Notes I | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 0.00%  
Other subsidiaries: | Unsubordinated debt | Fixed Rate Borrowings, Bonds and Notes I | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 14.30%  
Other subsidiaries: | Unsubordinated debt | Fixed Rate Borrowings, Bonds and Notes II    
Debt Instrument [Line Items]    
Long-term debt ¥ 30,185 59,522
Other subsidiaries: | Unsubordinated debt | Fixed Rate Borrowings, Bonds and Notes II | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 0.00%  
Other subsidiaries: | Unsubordinated debt | Fixed Rate Borrowings, Bonds and Notes II | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 9.50%  
Other subsidiaries: | Unsubordinated debt | Fixed Rate Borrowings, Bonds and Notes IV    
Debt Instrument [Line Items]    
Long-term debt ¥ 317,394 336,892
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 4.70%  
Other subsidiaries: | Unsubordinated debt | Fixed Rate Borrowings, Bonds and Notes V    
Debt Instrument [Line Items]    
Long-term debt ¥ 425,945 389,260
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 9.00%  
Other subsidiaries: | Unsubordinated debt | Floating/Adjustable Rate Borrowings, Bonds and Notes I    
Debt Instrument [Line Items]    
Long-term debt ¥ 622,569 683,131
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 27.11%  
Other subsidiaries: | Unsubordinated debt | Floating Rate Borrowings, Bonds and Notes I    
Debt Instrument [Line Items]    
Long-term debt ¥ 169,131 150,161
Other subsidiaries: | Unsubordinated debt | Floating Rate Borrowings, Bonds and Notes I | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 0.00%  
Other subsidiaries: | Unsubordinated debt | Floating Rate Borrowings, Bonds and Notes I | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 27.50%  
Other subsidiaries: | Unsubordinated debt | Adjustable Rate Bonds and Notes I    
Debt Instrument [Line Items]    
Long-term debt ¥ 0 170
Other subsidiaries: | Unsubordinated debt | Adjustable Rate Bonds and Notes I | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 0.10%  
Other subsidiaries: | Subordinated debt    
Debt Instrument [Line Items]    
Long-term debt ¥ 265,626 291,489
Other subsidiaries: | Subordinated debt | Fixed Rate Borrowings, Bonds and Notes I    
Debt Instrument [Line Items]    
Long-term debt ¥ 30,000 30,000
Other subsidiaries: | Subordinated debt | Fixed Rate Borrowings, Bonds and Notes I | Minimum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 1.92%  
Other subsidiaries: | Subordinated debt | Fixed Rate Borrowings, Bonds and Notes I | Maximum    
Debt Instrument [Line Items]    
Interest rate, stated percentage 2.61%  
Other subsidiaries: | Subordinated debt | Fixed Rate Borrowings, Bonds and Notes II    
Debt Instrument [Line Items]    
Long-term debt ¥ 2,049 2,386
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 ¥ 228,800 253,035
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 ¥ 4,777 ¥ 6,068
Interest rate, stated percentage 11.51%