EMPLOYEE BENEFITS PLANS (Tables)

3 Months Ended

Mar. 31, 2013

EMPLOYEE BENEFITS PLANS

Schedule of components of net periodic benefit cost for benefit plans

	Pension Benefits						Other Postretirement Benefits
	Three Months Ended, March 31,						Three Months Ended, March 31,
(Millions)	2013			2012			2013			2012
Service cost	$	7.5		$	12.4		$	6.5		$	5.5
Interest cost	17.8			19.8			6.3			7.2
Expected return on plan assets	(26.6		)	(27.1		)	(7.7		)	(7.0		)
Amortization of transition obligation	—			—			—			0.1
Amortization of prior service cost (credit)	1.0			1.2			(0.6		)	(0.9		)
Amortization of net actuarial loss	13.5			8.3			2.0			1.6
Net periodic benefit cost	$	13.2		$	14.6		$	6.5		$	6.5