EMPLOYEE BENEFIT PLANS (Tables)

3 Months Ended

Mar. 31, 2013

EMPLOYEE BENEFIT PLANS

Components of net periodic benefit cost

	Pension Benefits						Other Postretirement Benefits
	Three Months Ended, March 31						Three Months Ended, March 31
(Millions)	2013			2012			2013			2012
Service cost	$	2.7		$	3.4		$	2.7		$	2.2
Interest cost	7.8			8.7			3.3			3.7
Expected return on plan assets	(14.4		)	(13.9		)	(3.7		)	(3.6		)
Amortization of transition obligation	—			—			—			0.1
Amortization of prior service cost (credit)	0.9			1.1			(0.5		)	(0.8		)
Amortization of net actuarial loss	5.8			3.6			1.8			1.3
Net periodic benefit cost	$	2.8		$	2.9		$	3.6		$	2.9