v3.26.1
Loans and Allowance for Credit Losses (Total Outstanding Loans and Past Due Analysis) (Detail) - JPY (¥)
¥ in Millions
Mar. 31, 2026
Mar. 31, 2025
Loans and Leases Receivable Disclosure [Line Items]    
Total Loans ¥ 145,325,480 ¥ 131,881,305
Loans Held for Sale 1,253,647 887,263
Past Due 90 Days and Accruing 5,535 10,243
Unearned income, unamortized premiums—net and deferred loan fees—net (506,256) (442,790)
Total 144,819,224 131,438,515
1-3 months    
Loans and Leases Receivable Disclosure [Line Items]    
Total Loans 387,691 312,271
Greater Than 3 months    
Loans and Leases Receivable Disclosure [Line Items]    
Total Loans 339,170 350,566
Total Past Due    
Loans and Leases Receivable Disclosure [Line Items]    
Total Loans 726,861 662,837
Current    
Loans and Leases Receivable Disclosure [Line Items]    
Total Loans 143,344,972 130,331,205
Residential    
Loans and Leases Receivable Disclosure [Line Items]    
Total Loans 12,842,510 12,561,780
Loans Held for Sale 0 0
Past Due 90 Days and Accruing 2,656 3,157
Residential | 1-3 months    
Loans and Leases Receivable Disclosure [Line Items]    
Total Loans 29,796 32,739
Residential | Greater Than 3 months    
Loans and Leases Receivable Disclosure [Line Items]    
Total Loans 9,805 10,711
Residential | Total Past Due    
Loans and Leases Receivable Disclosure [Line Items]    
Total Loans 39,601 43,450
Residential | Current    
Loans and Leases Receivable Disclosure [Line Items]    
Total Loans 12,802,909 12,518,330
Card    
Loans and Leases Receivable Disclosure [Line Items]    
Total Loans 557,508 498,773
Loans Held for Sale 0 0
Past Due 90 Days and Accruing 0 0
Card | 1-3 months    
Loans and Leases Receivable Disclosure [Line Items]    
Total Loans 18,154 15,737
Card | Greater Than 3 months    
Loans and Leases Receivable Disclosure [Line Items]    
Total Loans 34,414 30,221
Card | Total Past Due    
Loans and Leases Receivable Disclosure [Line Items]    
Total Loans 52,568 45,958
Card | Current    
Loans and Leases Receivable Disclosure [Line Items]    
Total Loans 504,940 452,815
Krungsri    
Loans and Leases Receivable Disclosure [Line Items]    
Total Loans 9,844,777 8,846,908
Loans Held for Sale 19,964 0
Past Due 90 Days and Accruing 0 0
Krungsri | 1-3 months    
Loans and Leases Receivable Disclosure [Line Items]    
Total Loans 281,023 228,655
Krungsri | Greater Than 3 months    
Loans and Leases Receivable Disclosure [Line Items]    
Total Loans 228,683 252,745
Krungsri | Total Past Due    
Loans and Leases Receivable Disclosure [Line Items]    
Total Loans 509,706 481,400
Krungsri | Current    
Loans and Leases Receivable Disclosure [Line Items]    
Total Loans 9,315,107 8,365,508
Other    
Loans and Leases Receivable Disclosure [Line Items]    
Total Loans 2,215,973 2,056,692
Loans Held for Sale 0 0
Past Due 90 Days and Accruing 0 0
Other | 1-3 months    
Loans and Leases Receivable Disclosure [Line Items]    
Total Loans 17,972 21,555
Other | Greater Than 3 months    
Loans and Leases Receivable Disclosure [Line Items]    
Total Loans 26,260 28,744
Other | Total Past Due    
Loans and Leases Receivable Disclosure [Line Items]    
Total Loans 44,232 50,299
Other | Current    
Loans and Leases Receivable Disclosure [Line Items]    
Total Loans 2,171,741 2,006,393
Domestic | Commercial    
Loans and Leases Receivable Disclosure [Line Items]    
Total Loans 64,192,347 61,669,333
Loans Held for Sale 161,423 130,854
Past Due 90 Days and Accruing 2,879 2,419
Domestic | Commercial | 1-3 months    
Loans and Leases Receivable Disclosure [Line Items]    
Total Loans 5,227 9,275
Domestic | Commercial | Greater Than 3 months    
Loans and Leases Receivable Disclosure [Line Items]    
Total Loans 12,697 6,127
Domestic | Commercial | Total Past Due    
Loans and Leases Receivable Disclosure [Line Items]    
Total Loans 17,924 15,402
Domestic | Commercial | Current    
Loans and Leases Receivable Disclosure [Line Items]    
Total Loans 64,013,000 61,523,077
Foreign    
Loans and Leases Receivable Disclosure [Line Items]    
Total 67,245,022 56,713,215
Foreign | Commercial    
Loans and Leases Receivable Disclosure [Line Items]    
Total Loans 55,672,365 46,247,819
Loans Held for Sale 1,072,260 756,409
Past Due 90 Days and Accruing 0 4,667
Foreign | Commercial | 1-3 months    
Loans and Leases Receivable Disclosure [Line Items]    
Total Loans 35,519 4,310
Foreign | Commercial | Greater Than 3 months    
Loans and Leases Receivable Disclosure [Line Items]    
Total Loans 27,311 22,018
Foreign | Commercial | Total Past Due    
Loans and Leases Receivable Disclosure [Line Items]    
Total Loans 62,830 26,328
Foreign | Commercial | Current    
Loans and Leases Receivable Disclosure [Line Items]    
Total Loans ¥ 54,537,275 ¥ 45,465,082