EMPLOYEE BENEFIT PLANS - Employee Retirement Plans (Details)
$ in Millions
3 Months Ended
Mar. 31, 2018
USD ($)
plan
Mar. 31, 2017
USD ($)
plan
Employee Retirement Plans    
Number of frozen plans | plan 1 1
Salaries, wages and benefits expense    
Employee Retirement Plans    
Service costs $ 1 $ 1
Other non-operating income (expense), net    
Employee Retirement Plans    
Other components $ 4 $ 7