v3.25.2
Other Assets and Liabilities (Summarized Financial Information of Equity Method Investees, Other than Morgan Stanley) (Detail) - JPY (¥)
¥ in Millions
 12 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Mar. 31, 2023
Schedule of Equity Method Investments [Line Items]      
Total assets ¥ 405,940,211 ¥ 397,820,570 ¥ 382,177,876
Total liabilities 386,690,473 379,303,483  
Noncontrolling interests 964,252 841,350  
Equity Method Investment, Summarized Financial Information, Income and Loss      
Net income applicable to Morgan Stanley 1,267,638 1,377,569 414,561
Equity Method Investees Other than Morgan Stanley      
Schedule of Equity Method Investments [Line Items]      
Net loans 20,315,000 21,053,000  
Total assets 40,852,000 40,549,000  
Deposits 13,742,000 15,138,000  
Total liabilities 32,900,000 33,291,000  
Noncontrolling interests 93,000 87,000  
Equity Method Investment, Summarized Financial Information, Income and Loss      
Total interest income 1,998,000 1,820,000 1,428,000
Total interest expense 775,000 782,000 519,000
Net interest income 1,223,000 1,038,000 909,000
Provision for credit losses 366,000 291,000 245,000
Income before income tax expense 838,000 698,000 615,000
Net income applicable to Morgan Stanley ¥ 704,000 ¥ 596,000 ¥ 497,000