RETIREMENT AND POSTRETIREMENT BENEFIT PLANS - COMPONENTS OF NET PERIODIC BENEFIT COST (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Pension Benefits
Net periodic benefit costs:
Service cost — benefits earned during the period	$ 5	$ 6	$ 7
Interest cost on projected benefit obligation	15	17	18
Expected return on plan assets	(25)	(24)	(24)
Recognized actuarial loss	7	10	12
Other costs and adjustments	1	3	4
Net periodic benefit cost	3	12	17
Amounts that will be amortized from AOCI into net periodic benefit cost over the next fiscal year
Estimated net loss that will be amortized from AOCI into net periodic benefit cost over the next fiscal year	9
Estimated prior service cost that will be amortized from AOCI into net periodic benefit cost over the next fiscal year	0
Postretirement Benefits
Net periodic benefit costs:
Service cost — benefits earned during the period	23	21	20
Interest cost on projected benefit obligation	34	38	39
Expected return on plan assets	0	0	0
Recognized actuarial loss	14	14	15
Other costs and adjustments	(2)	1	0
Net periodic benefit cost	69	$ 74	$ 74
Amounts that will be amortized from AOCI into net periodic benefit cost over the next fiscal year
Estimated net loss that will be amortized from AOCI into net periodic benefit cost over the next fiscal year	9
Estimated prior service cost that will be amortized from AOCI into net periodic benefit cost over the next fiscal year	$ (8)