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PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS (Additional) (Detail) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2017
Mar. 31, 2016
Defined Benefit Plan Disclosure [Line Items]    
Defined contribution plan, employer contribution, maximum percentage 6.00%  
Defined contribution plan, expense relating to the plan $ 3.7 $ 3.2
Contributions made by the corporation to the plan 8.1  
Estimated future contributions for the current fiscal year $ 11.8