v3.26.1
RETIREMENT-RELATED BENEFITS - Plan Assets (Details) - USD ($)
$ in Millions
12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Retirement-Related Benefits      
Percentage of Co-sponsored plan assets 58.00%    
Pension Plans      
Retirement-Related Benefits      
Fair value of plan assets, gross $ 318 $ 301  
Investments measured at net asset value using NAV as a practical expedient 946 898  
Fair value of plan assets 1,264 1,199 $ 1,248
Pension Plans | Government and related      
Retirement-Related Benefits      
Fair value of plan assets, gross 109 104  
Pension Plans | Corporate bonds      
Retirement-Related Benefits      
Fair value of plan assets, gross 22 21  
Pension Plans | Insurance contracts      
Retirement-Related Benefits      
Fair value of plan assets, gross 179 169  
Pension Plans | Cash and short-term investments      
Retirement-Related Benefits      
Fair value of plan assets, gross 5 3  
Pension Plans | Derivative assets      
Retirement-Related Benefits      
Fair value of plan assets, gross 4 4  
Pension Plans | Level 1      
Retirement-Related Benefits      
Fair value of plan assets, gross 4 3  
Fair value of plan assets 4 3  
Pension Plans | Level 1 | Cash and short-term investments      
Retirement-Related Benefits      
Fair value of plan assets, gross 4 3  
Pension Plans | Level 2      
Retirement-Related Benefits      
Fair value of plan assets, gross 314 297  
Fair value of plan assets 314 297  
Pension Plans | Level 2 | Government and related      
Retirement-Related Benefits      
Fair value of plan assets, gross 109 104  
Pension Plans | Level 2 | Corporate bonds      
Retirement-Related Benefits      
Fair value of plan assets, gross 22 21  
Pension Plans | Level 2 | Insurance contracts      
Retirement-Related Benefits      
Fair value of plan assets, gross 179 169  
Pension Plans | Level 2 | Derivative assets      
Retirement-Related Benefits      
Fair value of plan assets, gross $ 4 $ 4