v3.25.2
Derivative instruments and hedging activities - Summary of Fair Value Hedges (Detail) - Fair value hedges [member] - Fixed rate bonds [member]
¥ in Millions
Mar. 31, 2025
JPY (¥)
Derivative Instruments And Hedging Activities [Line Items]  
Carrying amount of hedged items asset ¥ 485,960
Accumulative fair value hedge adjustments asset ¥ (3,330)