PENSION AND OTHER POST-EMPLOYMENT BENEFITS - Weighted-Average Asset Allocations (Details) - Pension Benefits	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Plan asset allocation	100.00%	100.00%
Temporary investment funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Plan asset allocation	1.00%	1.00%
Equity investment funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Plan asset allocation	41.00%	53.00%
Fixed income funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Plan asset allocation	58.00%	46.00%