EMPLOYEE BENEFIT PLANS - FUNDED STATUS (Details) - Qualified Defined Benefit [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Benefit obligation
Beginning of year	$ 2,602	$ 2,225
Service cost	46	42	$ 48
Interest cost	75	89	79
Actuarial (gain) loss	339	359
Defined Benefit Plan, Benefit Obligation, Benefits Paid	(134)	(113)
End of year	2,934	2,602	2,225
Defined Benefit Plan Service Cost, including early-out expense	52
Plan assets at fair value
Beginning of year	2,239	1,858
Actual return on plan assets	383	429
Employer contributions	0	65	0
Defined Benefit Plan, Plan Assets, Benefits Paid	(134)	(113)
End of year	2,488	2,239	$ 1,858
Funded status (unfunded)	$ (446)	$ (363)
Percent funded	85.00%	86.00%
Accumulated benefit obligation	$ 2,800	$ 2,400
Defined Benefit Plan, Plan Assets, Benefits Paid	$ 134	$ 113