EMPLOYEE BENEFIT PLANS (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Pension Benefits
Components of net periodic benefit cost (including amounts capitalized to the balance sheets)
Service cost	$ 2.2	$ 2.7	$ 6.5	$ 8.1
Interest cost	8.6	7.6	25.8	22.9
Expected return on plan assets	(16.0)	(14.3)	(48.0)	(42.9)
Loss on plan settlement	0	0	0.4	0
Amortization of prior service cost (credit)	0.1	0.9	0.4	2.7
Amortization of net actuarial losses	3.7	6.0	11.2	18.0
Net periodic benefit cost (credit)	(1.4)	2.9	(3.7)	8.8
Contributions to the plans			46.6
Other Postretirement Benefits
Components of net periodic benefit cost (including amounts capitalized to the balance sheets)
Service cost	1.9	2.6	5.8	7.9
Interest cost	2.7	3.4	8.8	10.1
Expected return on plan assets	(4.0)	(3.7)	(12.0)	(11.1)
Loss on plan settlement	0	0	0	0
Amortization of prior service cost (credit)	(2.3)	(0.6)	(5.7)	(1.6)
Amortization of net actuarial losses	0.7	1.9	2.0	5.6
Net periodic benefit cost (credit)	(1.0)	3.6	(1.1)	10.9
Contributions to the plans			0.1
Expected contributions to the plans during the remainder of fiscal year			$ 3.0