v3.26.1
Pledged Assets and Collateral (Associated Liabilities Collateralized by Pledged Assets) (Detail) - JPY (¥)
¥ in Millions
Mar. 31, 2026
Mar. 31, 2025
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]    
Deposits ¥ 794,000 ¥ 844,000
Call money and funds purchased 3,191,544 2,745,165
Payables under repurchase agreements 13,069,000 18,087,000
Payables under securities lending transactions 1,027,000 403,000
Other short-term borrowings 214,000 2,271,000
Long-term debt 3,888,000 576,000
Total 19,143,000 22,180,000
Collateral Pledged [Member]    
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]    
Call money and funds purchased ¥ 150 ¥ 0