v3.26.1
Variable Interest Entities and Securitizations - Additional Information (Detail) - JPY (¥)
¥ in Millions
Mar. 31, 2026
Mar. 31, 2025
Consolidated MHFG's balance sheets    
Noncontrolling interests ¥ 618,420 ¥ 484,909
Unconsolidated VIEs    
Consolidated MHFG's balance sheets    
Noncontrolling interests ¥ 509,000 ¥ 389,000