PENSION AND POSTRETIREMENT BENEFIT PLANS (Net Periodic Benefit Cost) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Percentage of plan assets attributable to the principal defined benefit pension plan	66.00%
Percentage of plan obligations attributable to the principal defined benefit pension plan	62.00%
Pension Plans, Defined Benefit [Member]
Retirement Benefits [Abstract]
Discount rate used to determine benefit obligations	3.10%	3.50%
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Service cost - benefits earned during the year	$ 25	$ 24	$ 25
Interest cost on projected benefit obligation	188	192	242
Expected return on plan assets	(411)	(418)	(405)
Amortization of prior service costs	(4)	(3)	(3)
Amortization of net actuarial (gain)/loss	82	84	91
Curtailments	(8)		(1)
Settlements	167	91	161
Special termination benefits	3	1
Total net periodic benefit cost/(credit)	$ 42	$ (29)	$ 110
Other Postretirement Benefit Plans, Defined Benefit [Member]
Retirement Benefits [Abstract]
Discount rate used to determine benefit obligations	3.30%	3.60%