EMPLOYEE RETIREMENT PLANS - Defined-benefit Pension Plans with an Accumulated Benefit Obligation in Excess of Plan Assets (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Qualified
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	$ 780	$ 670	$ 695
Information for the defined-benefit pension plans with an accumulated benefit obligation in excess of plan assets
Projected benefit obligation	1,019	882
Accumulated benefit obligation	1,019	882
Fair value of plan assets	763	655
Nonqualified Plan
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0	$ 0
Information for the defined-benefit pension plans with an accumulated benefit obligation in excess of plan assets
Projected benefit obligation	161	155
Accumulated benefit obligation	161	155
Fair value of plan assets	$ 0	$ 0