EMPLOYEE BENEFIT PLANS - FUNDED STATUS (Details) - Qualified Defined Benefit [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Benefit obligation
Beginning of year	$ 2,387	$ 2,043
Service cost	48	39	$ 37
Interest cost	79	74	73
Actuarial (gain) loss	(191)	300
Defined Benefit Plan, Benefit Obligation, Benefits Paid	(98)	(69)
End of year	2,225	2,387	2,043
Plan assets at fair value
Beginning of year	2,083	1,846
Actual return on plan assets	(127)	291
Employer contributions	0	15
Defined Benefit Plan, Plan Assets, Benefits Paid	(98)	(69)
End of year	1,858	2,083	$ 1,846
Funded status (unfunded)	$ (367)	$ (304)
Percent funded	84.00%	87.00%
Accumulated benefit obligation	$ 2,100	$ 2,200
Defined Benefit Plan, Plan Assets, Benefits Paid	$ 98	$ 69