BENEFITS

The components of our net periodic pension and Other Post-Retirement Employee Benefits (OPEB) costs for the three and nine months ended September 30 were as follows:



	Pension Costs
	Three Months Ended September 30						Nine Months Ended September 30
Benefit Plan Cost Components	2014			2013			2014			2013
	(Millions of Dollars)
Net Periodic Benefit Cost
Service cost	$	2.6		$	3.7		$	7.6		$	11.0
Interest cost	17.0			15.1			51.1			45.3
Expected return on plan assets	(24.7		)	(23.9		)	(74.0		)	(71.8		)
Amortization of:
Prior service cost	0.6			0.5			1.6			1.7
Actuarial loss	9.1			13.6			27.5			40.8
Net Periodic Benefit Cost	$	4.6		$	9.0		$	13.8		$	27.0



	OPEB Costs
	Three Months Ended September 30						Nine Months Ended September 30
Benefit Plan Cost Components	2014			2013			2014			2013
	(Millions of Dollars)
Net Periodic Benefit Cost
Service cost	$	2.1		$	2.5		$	6.4		$	7.5
Interest cost	4.4			3.9			13.3			11.7
Expected return on plan assets	(5.9		)	(5.4		)	(17.8		)	(16.0		)
Amortization of:
Transition obligation	—			—			—			—
Prior service (credit)	(0.4		)	(0.5		)	(1.3		)	(1.5		)
Actuarial loss	0.3			1.0			0.9			2.8
Net Periodic Benefit Cost	$	0.5		$	1.5		$	1.5		$	4.5

We made no contributions to our qualified benefit plans during the first nine months of 2014 and 2013. Future contributions to the plans will be dependent upon many factors, including the performance of existing plan assets and long-term discount rates.

Postemployment Benefits: Postemployment benefits provided to former or inactive employees are recognized when an event occurs. The estimated liability for such benefits was $4.2 million as of both September 30, 2014 and December 31, 2013.