v3.26.1
Noninterest Income - Additional Information (Detail) - JPY (¥)
¥ in Millions
12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Other Revenues [Line Items]      
Trust fees ¥ 64,000 ¥ 59,000 ¥ 58,000
Fees related to trust business 105,000 87,000 79,000
Trading account gains (losses)—net [1] 102,749 803,383 390,260
Other noninterest income [1],[2] 326,113 265,045 221,273
Accounting Standards Concepts Update 606      
Other Revenues [Line Items]      
Trading account gains (losses)—net 113,000 113,000 93,000
Other noninterest income ¥ 31,000 ¥ 33,000 ¥ 25,000
[1] Part of these amounts are considered to be revenues from contracts that are within the scope of ASC 606.
[2] These amounts include the net unrealized gains resulting from changes in fair values of structured notes that contain embedded derivatives. See Note 26 “Fair value” for further details.