v3.26.1
RETIREMENT-RELATED BENEFITS - Changes in Benefit Obligation and Plan Assets (Details) - Pension Plans - USD ($)
$ in Millions
12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Changes in benefit obligation      
Benefit obligation, at beginning of period $ 1,563 $ 1,670  
Service cost 32 34  
Interest cost 62 52 $ 55
Plan participants' contributions 3 3  
Actuarial losses (gains) (91) (53)  
Benefits paid from trust (24) (22)  
Direct benefit payments (43) (39)  
Foreign exchange impact 81 (2)  
Plan amendments 36    
Curtailments, settlements and other (45) (80)  
Benefit obligation, at end of period 1,575 1,563 1,670
Accumulated benefit obligation 1,492 1,484  
Change in plan assets      
Fair value of plan assets, at beginning of period 1,199 1,248  
Actual return on plan assets 37 15  
Employer contributions 12 17  
Plan participants' contributions 3 3  
Benefits paid from trust (24) (22)  
Foreign exchange impact 76 3  
Settlements (40) (65)  
Fair value of plan assets, at end of period 1,264 1,199 $ 1,248
Funded status at end of period $ (311) $ (364)