Benefit Plans and Other Postretirement Benefits (Tables)

3 Months Ended

Mar. 31, 2013

Benefit Plans and Other Postretirement Benefits [Abstract]

Components of Net Periodic Benefit Cost

Components of Net Periodic Benefit Cost

	Three Months Ended March 31
	2013			2012			2013			2012
(Thousands of Dollars)	Pension Benefits						Postretirement Health Care Benefits
Service cost	$	24,071		$	21,329		$	1,182		$	1,180
Interest cost		35,172			38,723			8,417			9,380
Expected return on plan assets		(49,613	)		(51,476	)		(8,253	)		(7,111	)
Amortization of transition obligation		-			-			206			3,580
Amortization of prior service cost (credit)		1,468			5,266			(2,438	)		(1,888	)
Amortization of net loss		36,038			26,318			5,646			3,965
Net periodic benefit cost		47,136			40,160			4,760			9,106
Costs not recognized and additional cost recognized due to the effects of regulation		(7,847	)		(9,133	)		-			973
Net benefit cost recognized for financial reporting	$	39,289		$	31,027		$	4,760		$	10,079