v3.26.1
Employee benefits - Summary of Amounts Recognized in Relation to Net Defined Benefit Liability Asset in Statements of Financial Position (Detail) - JPY (¥)
¥ in Millions
Mar. 31, 2026
Mar. 31, 2025
Disclosure of defined benefit plans [line items]    
Net defined benefit asset ¥ (129,765) ¥ (86,914)
Japanese Defined Benefit Plans [Member]    
Disclosure of defined benefit plans [line items]    
Present value of defined benefit obligations 387,432 488,818
Fair value of plan assets (418,453) (439,943)
The impact of minimum funding requirement and asset ceiling 0 10,147
Net defined benefit asset (127,452) (84,009)
Net defined benefit liability 96,431 143,031
Net amount (31,021) 59,022
Foreign Defined Benefit Plan [Member]    
Disclosure of defined benefit plans [line items]    
Present value of defined benefit obligations 139,768 130,259
Fair value of plan assets (81,261) (49,648)
The impact of minimum funding requirement and asset ceiling 3,319 3,225
Net defined benefit asset (2,314) (2,905)
Net defined benefit liability 64,140 86,741
Net amount ¥ 61,826 ¥ 83,836