EMPLOYEE BENEFIT PLANS - FUNDED STATUS (Details) - Qualified Defined Benefit [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Benefit obligation
Beginning of year	$ 2,225	$ 2,387
Service cost	42	48	$ 39
Interest cost	89	79	74
Actuarial (gain) loss	359	(191)
Defined Benefit Plan, Benefit Obligation, Benefits Paid	(113)	(98)
End of year	2,602	2,225	2,387
Plan assets at fair value
Beginning of year	1,858	2,083
Actual return on plan assets	429	(127)
Employer contributions	65	0	15
Defined Benefit Plan, Plan Assets, Benefits Paid	(113)	(98)
End of year	2,239	1,858	$ 2,083
Funded status (unfunded)	$ (363)	$ (367)
Percent funded	86.00%	84.00%
Accumulated benefit obligation	$ 2,400	$ 2,100
Defined Benefit Plan, Plan Assets, Benefits Paid	$ 113	$ 98