EMPLOYEE BENEFIT PLANS

9 Months Ended

Sep. 30, 2011

EMPLOYEE BENEFIT PLANS [Abstract]

EMPLOYEE BENEFIT PLANS

EMPLOYEE BENEFIT PLANS

The components of net periodic benefit cost related to our defined benefit plans were as follows:

	Pension Plans (a)						Other Postretirement Benefit Plans
	2011			2010			2011		2010
	(Thousands of Dollars)
For the three months ended September 30:
Components of net periodic benefit cost:
Service cost	$	3,136		$	2,846		$	264	$	226
Interest cost	720			559			222		208
Expected return on assets	(904		)	(577		)	—		—
Amortization of prior service credit	(4		)	(4		)	—		—
Amortization of net loss	120			132			18		21
Net periodic benefit cost	$	3,068		$	2,956		$	504	$	455
For the nine months ended September 30:
Components of net periodic benefit cost:
Service cost	$	9,348		$	8,538		$	777	$	678
Interest cost	2,160			1,675			666		624
Expected return on assets	(2,712		)	(1,735		)	—		—
Amortization of prior service credit	(12		)	(12		)	—		—
Amortization of net loss	362			404			54		63
Net periodic benefit cost	$	9,146		$	8,870		$	1,497	$	1,365

(a) Includes amounts related to the pension plan, the excess pension plan and the supplemental executive retirement plan.