BENEFITS Benefits - Weighted-average Assumptions (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Postemployment Benefits [Abstract]
Discount rate	3.88%	3.60%	4.29%
Tax exempt accounts	7.00%	7.00%	7.00%
Expected long term reurn on assets, taxable accounts	4.50%	4.50%	4.50%