EMPLOYEE BENEFIT PLANS - PLAN ASSETS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Qualified Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	$ 2,239	$ 1,858	$ 2,083
Plan asset allocations	100.00%	100.00%
Qualified Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	$ 2,126	$ 1,749
Qualified Defined Benefit [Member] | Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations	35.00%	53.00%
Qualified Defined Benefit [Member] | Credit bond index fund [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	$ 1,009	$ 1,135
Qualified Defined Benefit [Member] | Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations	6.00%	7.00%
Qualified Defined Benefit [Member] | Real Estate [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	$ 102	$ 104
Qualified Defined Benefit [Member] | Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	$ 11	$ 5
Qualified Defined Benefit [Member] | Defined Benefit Plan, Equity Securities, US
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations	41.00%	28.00%
Qualified Defined Benefit [Member] | Defined Benefit Plan, Equity Securities, US | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	$ 773	$ 431
Qualified Defined Benefit [Member] | Defined Benefit Plan, Equity Securities, Non-US
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations	18.00%	12.00%
Qualified Defined Benefit [Member] | Defined Benefit Plan, Equity Securities, Non-US | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	$ 344	$ 183
Qualified Defined Benefit Plan - Salaried [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations	100.00%	100.00%
Qualified Defined Benefit Plan - Salaried [Member] | Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations	90.00%	91.00%
Qualified Defined Benefit Plan - Salaried [Member] | Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations	0.00%	0.00%
Qualified Defined Benefit Plan - Salaried [Member] | Defined Benefit Plan, Equity Securities, US
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations	7.00%	6.00%
Qualified Defined Benefit Plan - Salaried [Member] | Defined Benefit Plan, Equity Securities, Non-US
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations	3.00%	3.00%
Minimum [Member] | Qualified Defined Benefit [Member] | Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	26
Minimum [Member] | Qualified Defined Benefit [Member] | Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	—
Minimum [Member] | Qualified Defined Benefit [Member] | Defined Benefit Plan, Equity Securities, US
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	36
Minimum [Member] | Qualified Defined Benefit [Member] | Defined Benefit Plan, Equity Securities, Non-US
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	13
Minimum [Member] | Qualified Defined Benefit Plan - Salaried [Member] | Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	86
Minimum [Member] | Qualified Defined Benefit Plan - Salaried [Member] | Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	—
Minimum [Member] | Qualified Defined Benefit Plan - Salaried [Member] | Defined Benefit Plan, Equity Securities, US
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	2
Minimum [Member] | Qualified Defined Benefit Plan - Salaried [Member] | Defined Benefit Plan, Equity Securities, Non-US
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	—
Maximum [Member] | Qualified Defined Benefit [Member] | Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	46
Maximum [Member] | Qualified Defined Benefit [Member] | Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	10
Maximum [Member] | Qualified Defined Benefit [Member] | Defined Benefit Plan, Equity Securities, US
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	46
Maximum [Member] | Qualified Defined Benefit [Member] | Defined Benefit Plan, Equity Securities, Non-US
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	23
Maximum [Member] | Qualified Defined Benefit Plan - Salaried [Member] | Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	95
Maximum [Member] | Qualified Defined Benefit Plan - Salaried [Member] | Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	—
Maximum [Member] | Qualified Defined Benefit Plan - Salaried [Member] | Defined Benefit Plan, Equity Securities, US
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	12
Maximum [Member] | Qualified Defined Benefit Plan - Salaried [Member] | Defined Benefit Plan, Equity Securities, Non-US
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	5