Benefits

9 Months Ended

Sep. 30, 2011

General Discussion of Pension and Other Postretirement Benefits [Abstract]

BENEFITS

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	2011			2010			2011			2010
	(Millions of Dollars)
Net Periodic Benefit Cost
Service cost	$	4.0		$	5.9		$	11.9		$	17.7
Interest cost	16.9			17.1			50.7			50.9
Expected return on plan assets	(20.5		)	(19.6		)	(61.6		)	(58.3		)
Amortization of:
Prior service cost	0.6			0.6			1.7			1.7
Actuarial loss	8.4			6.7			25.5			20.0
Net Periodic Benefit Cost	$	9.4		$	10.7		$	28.2		$	32.0

	OPEB Costs
	Three Months Ended September 30						Nine Months Ended September 30
Benefit Plan Cost Components	2011			2010			2011			2010
	(Millions of Dollars)
Net Periodic Benefit Cost
Service cost	$	2.6		$	2.8		$	7.8		$	8.4
Interest cost	5.2			5.3			15.6			15.8
Expected return on plan assets	(4.3		)	(3.6		)	(12.7		)	(10.8		)
Amortization of:
Transition obligation	—			0.1			0.2			0.3
Prior service (credit)	(0.4		)	(3.0		)	(1.4		)	(8.9		)
Actuarial loss	1.7			2.7			4.7			8.1
Net Periodic Benefit Cost	$	4.8		$	4.3		$	14.2		$	12.9

In January 2011, we contributed $122.4 million to our qualified benefit plans. In September 2011, we contributed $135.0 million to our qualified benefit plans. 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 $13.5 million as of September 30, 2011 and $14.8 million as of December 31, 2010.