EMPLOYEE BENEFIT PLANS (Details 5) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Significant Assumptions Used in Determining Net Periodic Benefit Cost
Expected return on plan assets (as a percent)	8.25%
Stock Purchase Saving Plan
Maximum percentage of eligible earnings from plan allowed to be deferred (as a percent)		25.00%
Percentage of employer's matching contribution for up to 6% of eligible employee contribution (as a percent)		100.00%
Maximum percentage of employee contribution eligible for employer' matching contribution towards defined contribution plan (as a percent)		6.00%
Matching employer's contribution to the plan		$ 21,800,000	$ 20,800,000	$ 21,000,000
Pension Benefits
Components of Net Periodic Benefit Cost
Service cost		18,300,000	17,900,000	15,500,000
Interest cost		43,500,000	44,000,000	44,900,000
Expected return on assets		(63,700,000)	(61,400,000)	(50,800,000)
Prior service cost amortization		7,000,000	7,000,000	7,000,000
Amortization of actuarial loss		12,200,000	16,000,000	23,400,000
Net periodic benefit cost		17,300,000	23,500,000	40,000,000
Changes in plan assets and benefit obligations recognized in other comprehensive income
Current year actuarial (gain)/loss		2,900,000	(26,400,000)	(10,400,000)
Amortization of actuarial losses		(400,000)	(2,000,000)	(3,700,000)
Amortization of prior service cost		(200,000)	(100,000)	(100,000)
Prior service cost OCI adjustment			800,000
Total recognized in other comprehensive income		2,300,000	(27,700,000)	(14,200,000)
Significant Assumptions Used in Determining Net Periodic Benefit Cost
Discount rate (as a percent)		5.56%	5.75%	6.45%
Expected return on plan assets (as a percent)		8.25%	8.50%	8.50%
Rate of compensation increase (as a percent)		4.00%	4.00%	4.00%
Estimated amount to be amortized from accumulated other comprehensive income into net periodic benefit costs in next year
Actuarial loss	600,000
Prior service cost	200,000
Total	800,000
Other Postretirement Benefits
Components of Net Periodic Benefit Cost
Service cost		4,300,000	4,200,000	3,700,000
Interest cost		12,200,000	11,900,000	12,300,000
Prior service cost amortization		1,000,000	1,000,000	1,000,000
Amortization of actuarial loss		400,000
Transition obligation amortization		700,000	700,000	700,000
Net periodic benefit cost		18,600,000	17,800,000	17,700,000
Changes in plan assets and benefit obligations recognized in other comprehensive income
Current year actuarial (gain)/loss		400,000	(100,000)	700,000
Amortization of prior service cost		(100,000)		(100,000)
Amortization of transition obligation		(100,000)	(100,000)	(100,000)
Total recognized in other comprehensive income		200,000	(200,000)	500,000
Significant Assumptions Used in Determining Net Periodic Benefit Cost
Discount rate (as a percent)		5.72%	5.90%	6.45%
Rate of compensation increase (as a percent)		4.00%	4.00%	4.00%
Health care cost trend rate (as a percent)		8.00%	8.50%	8.00%
Ultimate health care cost trend rate (as a percent)		5.00%	5.00%	5.00%
Estimated amount to be amortized from accumulated other comprehensive income into net periodic benefit costs in next year
Prior service cost	100,000
Transition obligation	100,000
Total	200,000
Effect of a one-percent increase or decrease in the assumed health care cost trend rate on total service and interest cost		$ 100,000