PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS - Rates Used to Estimate Our Net Periodic Benefit Costs (Details)	6 Months Ended		12 Months Ended
	Dec. 31, 2014	Jun. 30, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
United States Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Discount rates	4.40%	4.90%	4.10%		3.70%
United States Pension Plans | Salaried
Defined Benefit Plan Disclosure [Line Items]
Rate of compensation increase, current year			2.50%	2.50%	2.50%
Rate of compensation increase, thereafter			3.50%	3.50%	3.50%
United States Pension Plans | Hourly
Defined Benefit Plan Disclosure [Line Items]
Rate of compensation increase			3.00%	3.00%	3.00%
United States Other Postretirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Discount rates			3.60%	4.00%	3.00%
Canadian Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Discount rates			3.90%	4.70%	4.10%
Canadian Pension Plans | Salaried
Defined Benefit Plan Disclosure [Line Items]
Rate of compensation increase, current year			2.50%	2.50%	2.50%
Rate of compensation increase, thereafter			3.50%	3.50%	3.50%
Canadian Pension Plans | Hourly
Defined Benefit Plan Disclosure [Line Items]
Rate of compensation increase			3.25%	3.25%	3.25%
Canadian Other Postretirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Discount rates			3.80%	4.60%	4.00%
Qualified and Registered Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets			9.00%	9.00%	9.00%
Non Registered Canadian Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets			3.50%	3.50%	3.50%
Pension
Defined Benefit Plan Disclosure [Line Items]
Election of lump sum distributions (U.S. salaried and nonqualified plans only)			60.00%	60.00%	56.00%