Retirement Benefits (Tables)

6 Months Ended

Jun. 30, 2011

Retirement Benefits

Components of net periodic benefit cost

	Three months ended June 30,
	Pension Benefits						SERP						OPEB
	2011			2010			2011			2010			2011			2010
Service cost	$	1,404		$	1,273		$	27		$	17		$	507		$	509
Interest cost	2,612			2,550			51			39			1,062			1,063
Expected return on plan assets	(2,889		)	(2,483		)	—			—			(1,028		)	(966		)
Amortization of prior service cost (1)	133			133			(2		)	(2		)	(253		)	(253		)
Amortization of net actuarial loss (1)	1,395			1,033			52			32			381			344
Net periodic benefit cost	$	2,655		$	2,506		$	128		$	86		$	669		$	697

	Six months ended June 30,
	Pension Benefits						SERP						OPEB
	2011			2010			2011			2010			2011			2010
Service cost	$	2,798		$	2,546		$	47		$	34		$	1,133		$	1,018
Interest cost	5,203			5,100			91			79			2,192			2,125
Expected return on plan assets	(5,569		)	(4,966		)	—			—			(2,078		)	(1,933		)
Amortization of prior service cost (1)	266			266			(4		)	(4		)	(505		)	(506		)
Amortization of net actuarial loss (1)	2,747			2,067			85			63			881			689
Net periodic benefit cost	$	5,445		$	5,013		$	219		$	172		$	1,623		$	1,393

	Twelve months ended June 30,
	Pension Benefits						SERP						OPEB
	2011			2010			2011			2010			2011			2010
Service cost	$	5,139		$	5,148		$	83		$	65		$	2,253		$	1,885
Interest cost	10,218			10,047			166			152			4,396			3,980
Expected return on plan assets	(10,450		)	(10,143		)	—			—			(3,990		)	(3,845		)
Amortization of prior service cost (1)	531			568			(8		)	(8		)	(1,011		)	(1,011		)
Amortization of net actuarial loss (1)	4,676			3,658			118			115			1,691			970
Net periodic benefit cost	$	10,114		$	9,278		$	359		$	324		$	3,339		$	1,979

(1) Amounts are amortized from our regulatory asset originally recorded upon recognizing our net pension liability on the balance sheet.