Interim Pension and Other Postretirement Benefits (Table)

6 Months Ended

Mar. 31, 2016

General Discussion of Pension and Other Postretirement Benefits [Abstract]

Components of net periodic pension cost table

The components of our net periodic pension cost for our pension and other postretirement benefit plans for the three and six months ended March 31, 2016 and 2015 are presented in the following table. Most of these costs are recoverable through our gas distribution rates; however, a portion of these costs is capitalized into our gas distribution rate base. The remaining costs are recorded as a component of operation and maintenance expense.

	Three Months Ended March 31
	Pension Benefits						Other Benefits
	2016			2015			2016			2015
	(In thousands)
Components of net periodic pension cost:
Service cost	$	4,697		$	5,051		$	2,706		$	3,896
Interest cost	7,094			6,698			3,106			3,597
Expected return on assets	(6,880		)	(6,437		)	(1,566		)	(1,608		)
Amortization of transition obligation	—			—			20			68
Amortization of prior service credit	(56		)	(47		)	(411		)	(411		)
Amortization of actuarial (gain) loss	3,320			3,916			(542		)	—
Net periodic pension cost	$	8,175		$	9,181		$	3,313		$	5,542

	Six Months Ended March 31
	Pension Benefits						Other Benefits
	2016			2015			2016			2015
	(In thousands)
Components of net periodic pension cost:
Service cost	$	9,395		$	10,102		$	5,412		$	7,792
Interest cost	14,189			13,397			6,212			7,193
Expected return on assets	(13,761		)	(12,873		)	(3,132		)	(3,216		)
Amortization of transition obligation	—			—			41			136
Amortization of prior service credit	(113		)	(96		)	(822		)	(822		)
Amortization of actuarial (gain) loss	6,640			7,833			(1,084		)	—
Net periodic pension cost	$	16,350		$	18,363		$	6,627		$	11,083

Schedule of assumptions used table text block

The assumptions used to develop our net periodic pension cost for the three and six months ended March 31, 2016 and 2015 are as follows:

	Pension Benefits		Other Benefits
	2016	2015	2016	2015
Discount rate	4.55%	4.43%	4.55%	4.43%
Rate of compensation increase	3.50%	3.50%	N/A	N/A
Expected return on plan assets	7.00%	7.25%	4.45%	4.60%