v3.25.2
Employee benefits - Summary of Changes in the Plan Assets (Detail) - JPY (¥)
¥ in Millions
 12 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Japanese Defined Benefit Plans [Member]    
Disclosure of net defined benefit liability (asset) [line items]    
Beginning balance of the fiscal year ¥ 88,753  
Remeasurements:    
Ending balance of the fiscal year 59,022 ¥ 88,753
Foreign Defined Benefit Plan [Member]    
Disclosure of net defined benefit liability (asset) [line items]    
Beginning balance of the fiscal year 82,551  
Remeasurements:    
Ending balance of the fiscal year 83,836 82,551
Plan assets [member] | Japanese Defined Benefit Plans [Member]    
Disclosure of net defined benefit liability (asset) [line items]    
Beginning balance of the fiscal year 464,376 447,747
Interest income 7,047 5,424
Remeasurements:    
Return on plan assets excluding interest income (9,997) 32,764
Employer contribution 2,362 2,316
Benefits paid (23,845) (23,875)
Ending balance of the fiscal year 439,943 464,376
Plan assets [member] | Foreign Defined Benefit Plan [Member]    
Disclosure of net defined benefit liability (asset) [line items]    
Beginning balance of the fiscal year 47,893 56,987
Interest income 2,202 2,592
Remeasurements:    
Return on plan assets excluding interest income 1,330 (2,485)
Translation adjustments (462) 7,521
Employer contribution 5,645 5,381
Plan participants' contributions 359 585
Benefits paid (7,319) (10,603)
Curtailments and settlements [1]   (12,085)
Ending balance of the fiscal year ¥ 49,648 ¥ 47,893
[1] Curtailments and settlements of the foreign plans for the fiscal year ended March 31, 2024 relate mainly to the termination of the defined benefit pension plan at certain U.S. subsidiaries. Curtailments and settlements of the foreign plans for the fiscal year ended March 31, 2025 relate mainly to the termination of the defined benefit pension plan at certain U.S. subsidiaries.