EMPLOYEE BENEFIT PLANS (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Pension Benefits
Components of net periodic benefit cost (including amounts capitalized to the balance sheet) for our benefit plans
Service cost	$ 2.7	$ 3.4
Interest cost	7.8	8.7
Expected return on plan assets	(14.4)	(13.9)
Amortization of prior service cost (credit)	0.9	1.1
Amortization of net actuarial loss	5.8	3.6
Net periodic benefit cost	2.8	2.9
Contribution to the plans	37.6
Additional contributions to plans during the remainder of fiscal year	2.9
Other Postretirement Benefits
Components of net periodic benefit cost (including amounts capitalized to the balance sheet) for our benefit plans
Service cost	2.7	2.2
Interest cost	3.3	3.7
Expected return on plan assets	(3.7)	(3.6)
Amortization of transition obligation		0.1
Amortization of prior service cost (credit)	(0.5)	(0.8)
Amortization of net actuarial loss	1.8	1.3
Net periodic benefit cost	3.6	2.9
Additional contributions to plans during the remainder of fiscal year	$ 15.6