EMPLOYEE BENEFIT PLANS - NET PENSION EXPENSE (Details) - Qualified Defined Benefit [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	$ 39	$ 37	$ 41
Interest cost	74	73	84
Expected return on assets	(106)	(108)	(122)
Amortization of prior service cost	(1)	(1)	(1)
Recognized actuarial loss	26	25	26
Settlement expense (special item)	0	0	14
Net pension expense	$ 32	$ 26	42
Plan settlement			$ (62)