EMPLOYEE RETIREMENT PLANS - Net Periodic Pension Cost for Defined-benefit Pension Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net periodic pension cost for the company's defined-benefit pension plans
Pre-tax net loss from accumulated other comprehensive income (loss) into net periodic pension cost	$ 26
Qualified
Net periodic pension cost for the company's defined-benefit pension plans
Service cost	3	$ 3	$ 3
Interest cost	39	36	44
Expected return on plan assets	(44)	(48)	(46)
Amortization of net loss	18	17	19
Net periodic pension cost	16	8	20
Nonqualified Plan
Net periodic pension cost for the company's defined-benefit pension plans
Service cost	0	0	0
Interest cost	6	6	6
Expected return on plan assets	0	0	0
Amortization of net loss	2	3	3
Net periodic pension cost	$ 8	$ 9	$ 9