Benefit Plans and Other Postretirement Benefits (Tables)

9 Months Ended

Sep. 30, 2012

Benefit Plans and Other Postretirement Benefits [Abstract]

Components of Net Periodic Benefit Cost

Components of Net Periodic Benefit Cost

	Three Months Ended Sept. 30
	2012			2011			2012			2011
							Postretirement Health
(Thousands of Dollars)	Pension Benefits						Care Benefits
Service cost	$	2,130		$	1,923		$	314		$	273
Interest cost		4,900			5,008			707			681
Expected return on plan assets		(6,232	)		(6,579	)		(675	)		(752	)
Amortization of transition obligation		-			-			386			417
Amortization of prior service cost (credit)		360			376			(37	)		(12	)
Amortization of net loss		3,203			2,262			314			213
Net periodic benefit cost		4,361			2,990			1,009			820
Cost not recognized due to the effects of regulation		(1,076	)		(575	)		-			-
Net benefit cost recognized for financial reporting	$	3,285		$	2,415		$	1,009		$	820

	Nine Months Ended Sept. 30
	2012			2011			2012			2011
							Postretirement Health
(Thousands of Dollars)	Pension Benefits						Care Benefits
Service cost	$	6,390		$	5,768		$	944		$	819
Interest cost		14,700			15,026			2,123			2,042
Expected return on plan assets		(18,696	)		(19,737	)		(2,026	)		(2,255	)
Amortization of transition obligation		-			-			1,159			1,252
Amortization of prior service cost (credit)		1,079			1,129			(111	)		(38	)
Amortization of net loss		9,610			6,785			942			641
Net periodic benefit cost		13,083			8,971			3,031			2,461
Cost not recognized due to the effects of regulation		(3,226	)		(1,725	)		-			-
Net benefit cost recognized for financial reporting	$	9,857		$	7,246		$	3,031		$	2,461