EMPLOYEE BENEFIT PLANS (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Pension Benefits
Components of net periodic benefit cost (including amounts capitalized to the balance sheets)
Service cost	$ 2.7	$ 3.0	$ 5.4	$ 6.4
Interest cost	7.5	8.3	15.3	17.0
Expected return on plan assets	(14.2)	(13.8)	(28.6)	(27.7)
Amortization of transition obligation	0	0	0	0
Amortization of prior service cost (credit)	0.9	1.2	1.8	2.3
Amortization of net actuarial loss	6.2	3.8	12.0	7.4
Net periodic benefit cost	3.1	2.5	5.9	5.4
Contribution to the plans			37.7
Additional contributions to plans during the remainder of fiscal year	1.1		1.1
Other Postretirement Benefits
Components of net periodic benefit cost (including amounts capitalized to the balance sheets)
Service cost	2.6	2.1	5.3	4.3
Interest cost	3.4	3.8	6.7	7.5
Expected return on plan assets	(3.7)	(3.7)	(7.4)	(7.3)
Amortization of transition obligation	0	0	0	0.1
Amortization of prior service cost (credit)	(0.5)	(0.7)	(1.0)	(1.5)
Amortization of net actuarial loss	1.9	1.5	3.7	2.8
Net periodic benefit cost	3.7	3.0	7.3	5.9
Contribution to the plans			0.1
Additional contributions to plans during the remainder of fiscal year	$ 15.6		$ 15.6