EMPLOYEE BENEFIT PLANS - FUNDED STATUS (Details) - Qualified Defined Benefit [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Benefit obligation
Beginning of year	$ 2,043	$ 1,898
Service cost	39	37	$ 41
Interest cost	74	73	84
Actuarial (gain) loss	300	104
Benefits paid	(69)	(69)
End of year	2,387	2,043	1,898
Plan assets at fair value
Beginning of year	1,846	1,737
Actual return on plan assets	291	178
Employer contributions	15	0
Benefits paid	(69)	(69)
End of year	2,083	1,846	$ 1,737
Funded status (unfunded)	$ (304)	$ (197)
Percent funded	87.00%	90.00%
Accumulated benefit obligation	$ 2,200	$ 1,900