Employee and Retiree Benefit Plans (Tables)

9 Months Ended

Sep. 30, 2011

Components of Net Periodic Benefit Expense

The table that follows provides the components of net periodic benefit expense for the three-month and nine-month periods ended September 30, 2011 and 2010.

	Three Months Ended September 30,
	Pension Benefits						Other Postretirement Benefits
(Thousands of dollars)	2011			2010			2011			2010
Service cost	$	5,915			5,282			1,289			921
Interest cost		7,919			7,480			1,719			1,474
Expected return on plan assets		(6,840	)		(5,933	)		0			0
Amortization of prior service cost		337			387			(66	)		(67	)
Amortization of transitional asset		(51	)		(127	)		3			0
Recognized actuarial loss		2,543			2,995			786			596
		9,823			10,084			3,731			2,924
Termination benefits expense		700			0			0			0
Curtailment expense (gain)		1,105			0			(605	)		0
Net periodic benefit expense	$	11,628			10,084			3,126			2,924

	Nine Months Ended September 30,
	Pension Benefits						Other Postretirement Benefits
(Thousands of dollars)	2011			2010			2011			2010
Service cost	$	17,763			15,738			3,803			2,729
Interest cost		23,855			22,361			5,084			4,379
Expected return on plan assets		(20,634	)		(17,675	)		0			0
Amortization of prior service cost		1,020			1,158			(196	)		(197	)
Amortization of transitional asset		(155	)		(383	)		7			0
Recognized actuarial loss		7,661			8,948			2,326			1,770
		29,510			30,147			11,024			8,681
Termination benefits expense		700			0			0			0
Curtailment expense (gain)		1,105			0			(605	)		0
Net periodic benefit expense	$	31,315			30,147			10,419			8,681