BENEFITS Benefits - Weighted-average Assumptions (Details)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Postemployment Benefits [Abstract]
Discount rate	3.60%	4.29%	3.66%
Tax exempt accounts	7.00%	7.00%	7.00%
Expected long term reurn on assets, taxable accounts	4.50%	4.50%	4.50%