v3.26.1
Employee benefits - Summary of Changes in the Plan Assets (Detail) - JPY (¥)
¥ in Millions
 12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Japanese Defined Benefit Plans [Member]    
Disclosure of net defined benefit liability (asset) [line items]    
Beginning balance of the fiscal year ¥ 59,022  
Remeasurements:    
Ending balance of the fiscal year (31,021) ¥ 59,022
Foreign Defined Benefit Plan [Member]    
Disclosure of net defined benefit liability (asset) [line items]    
Beginning balance of the fiscal year 83,836  
Remeasurements:    
Ending balance of the fiscal year 61,826 83,836
Plan assets [member] | Japanese Defined Benefit Plans [Member]    
Disclosure of net defined benefit liability (asset) [line items]    
Beginning balance of the fiscal year 439,943 464,376
Interest income 9,139 7,047
Remeasurements:    
Return on plan assets excluding interest income 15,806 (9,997)
Employer contribution 858 2,362
Plan participants' contributions 0  
Benefits paid (22,571) (23,845)
Impact from loss of control of the Financial Services business [1] (24,722)  
Ending balance of the fiscal year 418,453 439,943
Plan assets [member] | Foreign Defined Benefit Plan [Member]    
Disclosure of net defined benefit liability (asset) [line items]    
Beginning balance of the fiscal year 49,648 47,893
Interest income 2,418 2,202
Remeasurements:    
Return on plan assets excluding interest income (1,515) 1,330
Translation adjustments 6,233 (462)
Employer contribution 3,900 5,645
Plan participants' contributions 291 359
Benefits paid (7,949) (7,319)
Curtailments and settlements (349)  
Other [2] 28,584  
Ending balance of the fiscal year ¥ 81,261 ¥ 49,648
[1] The figures for the fiscal year ended March 31, 2026 include the impact of the deconsolidation of SFGI, which operates the Financial Services business, resulting from the execution of the Partial Spin-off of the Financial Services business.
[2] The increase for the fiscal year ended March 31, 2026 is primarily attributable to contributions to plan assets associated with the establishment of new trust agreements at certain overseas subsidiaries.