RETIREMENT AND POSTRETIREMENT BENEFIT PLANS - POSTRETIREMENT AND OTHER BENEFIT PLANS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
POST RETIREMENT AND OTHER BENEFIT PLANS
Total benefit costs, including postretirement costs	$ 181	$ 182	$ 200