PENSION AND POST-RETIREMENT PLANS (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended	3 Months Ended
	Jun. 30, 2014	Jun. 30, 2014 Nonqualified Pension Plans [Member]	Jun. 30, 2013 Nonqualified Pension Plans [Member]	Jun. 30, 2014 Postretirement Benefit Plans [Member]	Jun. 30, 2013 Postretirement Benefit Plans [Member]
Components of Net Periodic Benefit Cost
Service cost		$ 1.7	$ 1.4	$ 0.5	$ 0.5
Interest cost		4.7	4.3	1.3	1.1
Expected return on plan assets		(7.0)	(5.9)
Amortization of net loss		1.5	3.4	0.3	0.2
Amortization of prior service cost		(1.2)	(1.1)
Net periodic benefit cost		(0.3)	2.1	2.1	1.8
Estimated full year cash contributions to pension plan		6.5
Employer contribution	$ 1.7