EMPLOYEE BENEFIT PLANS (Details 3) (Nonunion Defined Benefit Pension Plan)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Employee Benefit Plans
Period over which the possibility of experiencing a substantial loss is limited by adequate diversification under the long-term asset allocation policy	1 year
Weighted-average asset allocation
Total (as a percent)	100.00%	100.00%
Minimum
Target allocations and acceptable ranges
Performance period of recognized market indices used to compare investment performance	3 years
Maximum
Target allocations and acceptable ranges
Performance period of recognized market indices used to compare investment performance	5 years
Large Cap U.S. Equity
Weighted-average asset allocation
Total (as a percent)	32.10%	31.10%
Target allocations and acceptable ranges
Target allocation (as a percent)	30.00%
Acceptable Range, minimum (as a percent)	25.00%
Acceptable Range, maximum (as a percent)	35.00%
Mid Cap U.S. Equity
Weighted-average asset allocation
Total (as a percent)	11.10%	10.30%
Target allocations and acceptable ranges
Target allocation (as a percent)	10.00%
Acceptable Range, minimum (as a percent)	8.00%
Acceptable Range, maximum (as a percent)	12.00%
Small Cap U.S. Equity
Weighted-average asset allocation
Total (as a percent)	11.10%	10.50%
Target allocations and acceptable ranges
Target allocation (as a percent)	10.00%
Acceptable Range, minimum (as a percent)	8.00%
Acceptable Range, maximum (as a percent)	12.00%
International Equity
Weighted-average asset allocation
Total (as a percent)	11.10%	8.40%
Target allocations and acceptable ranges
Target allocation (as a percent)	10.00%
Acceptable Range, minimum (as a percent)	8.00%
Acceptable Range, maximum (as a percent)	12.00%
Emerging Market Equity
Weighted-average asset allocation
Total (as a percent)	5.00%	5.50%
Target allocations and acceptable ranges
Target allocation (as a percent)	5.00%
Acceptable Range, minimum (as a percent)	3.00%
Acceptable Range, maximum (as a percent)	7.00%
Debt Instruments
Weighted-average asset allocation
Total (as a percent)	22.40%	16.60%
Target allocations and acceptable ranges
Target allocation (as a percent)	20.00%
Acceptable Range, minimum (as a percent)	15.00%
Acceptable Range, maximum (as a percent)	30.00%
Floating Rate Loan Fund
Weighted-average asset allocation
Total (as a percent)	4.00%	4.10%
Target allocations and acceptable ranges
Target allocation (as a percent)	5.00%
Acceptable Range, minimum (as a percent)	3.00%
Acceptable Range, maximum (as a percent)	7.00%
Cash and Cash Equivalents
Weighted-average asset allocation
Total (as a percent)	3.20%	13.50%
Target allocations and acceptable ranges
Target allocation (as a percent)	10.00%
Acceptable Range, minimum (as a percent)	0.00%
Acceptable Range, maximum (as a percent)	15.00%
Actively managed portfolio of short-term debt instruments
Target allocations and acceptable ranges
Maximum maturity period of investments under investment restrictions	7 years
Maximum percentage of portfolio investments under investment restrictions represented by a single issue or issuer other than U.S. government securities	5.00%
Maximum percentage of portfolio under investment restrictions invested in BBB rated debt or collectively in mortgage-backed securities and asset-backed securities	25.00%
Actively managed portfolio of short duration debt instruments
Target allocations and acceptable ranges
Maximum average effective duration period of investments under investment restrictions	3 years