Annual report pursuant to Section 13 and 15(d)

PENSIONS AND OTHER POSTRETIREMENT BENEFITS (Additional Information) (Details)

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PENSIONS AND OTHER POSTRETIREMENT BENEFITS (Additional Information) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Pension Benefits [Member]    
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]    
Actual return on plan assets $ 100.2 $ 54.8
Other Benefits [Member]    
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]    
Actual return on plan assets $ 24.2 $ 16.0