EMPLOYEE BENEFIT PLANS - ASSUMPTIONS (DETAILS)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Benefit obligations, Weighted-average discount rate	3.95%	4.65%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Defined Benefit Plan, Year that Rate Reaches Ultimate Trend Rate	2028
Medical Cost [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Net period benefit costs, Assumed health care cost trend rate	8.30%
Prescription Drug Costs [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Net period benefit costs, Assumed health care cost trend rate	8.30%
Dental Costs [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Net period benefit costs, Assumed health care cost trend rate	5.00%
Vision Costs [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Net period benefit costs, Assumed health care cost trend rate	4.00%
Qualified Defined Benefit [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Benefit obligations, Weighted-average discount rate	3.95%	4.65%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Net period benefit costs, Weighted-average discount rate	4.65%	5.55%	5.85%
Net period benefit costs, Weighted-average expected return on assets	7.25%	7.75%	7.75%
Qualified Defined Benefit [Member] | Minimum [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Benefit obligations, Rate of compensation increase	3.05%	2.94%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Net period benefit costs, Rate of compensation increase	2.94%	2.99%	3.21%
Qualified Defined Benefit [Member] | Maximum [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Benefit obligations, Rate of compensation increase	4.02%	4.17%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Net period benefit costs, Rate of compensation increase	4.17%	4.35%	4.53%
Nonqualified Defined Benefit [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Benefit obligations, Weighted-average discount rate	3.95%	4.65%
Benefit obligations, Rate of compensation increase	5.00%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Net period benefit costs, Weighted-average discount rate	4.65%	5.55%	5.85%
Net period benefit costs, Rate of compensation increase		5.00%	5.00%
Nonqualified Defined Benefit [Member] | First Four Years of Employment [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Net period benefit costs, Rate of compensation increase	7.00%
Nonqualified Defined Benefit [Member] | Employment after First Four Years [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Net period benefit costs, Rate of compensation increase	5.00%
Postretirement Medical Benefits [Member] | Medical, Prescription Drugs and Dental Costs [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Net period benefit costs, Ultimate assumed trend rate	4.70%
Postretirement Medical Benefits [Member] | Vision Costs [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Net period benefit costs, Ultimate assumed trend rate	4.00%