Interim Pension and Other Postretirement Benefit Plan Information

3 Months Ended

Dec. 31, 2015

General Discussion of Pension and Other Postretirement Benefits [Abstract]

Interim Pension and Postretirement Benefit Plans

Interim Pension and Other Postretirement Benefit Plan Information

The components of our net periodic pension cost for our pension and other postretirement benefit plans for the three months ended December 31, 2015 and 2014 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 December 31
	Pension Benefits						Other Benefits
	2015			2014			2015			2014
	(In thousands)
Components of net periodic pension cost:
Service cost	$	4,698		$	5,051		$	2,706		$	3,896
Interest cost	7,095			6,699			3,106			3,596
Expected return on assets	(6,881		)	(6,436		)	(1,566		)	(1,608		)
Amortization of transition obligation	—			—			21			68
Amortization of prior service credit	(57		)	(49		)	(411		)	(411		)
Amortization of actuarial loss	3,320			3,917			(542		)	—
Net periodic pension cost	$	8,175		$	9,182		$	3,314		$	5,541

The assumptions used to develop our net periodic pension cost for the three months ended December 31, 2015 and 2014 are as follows:

	Pension Benefits				Other Benefits
	2015		2014		2015		2014
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	%

The discount rate used to compute the present value of a plan’s liabilities generally is based on rates of high-grade corporate bonds with maturities similar to the average period over which the benefits will be paid. Generally, our funding policy has been to contribute annually an amount in accordance with the requirements of the Employee Retirement Income Security Act of 1974. In accordance with the Pension Protection Act of 2006 (PPA), we determined the funded status of our plans as of January 1, 2016. Based on that determination, we are not required to make a minimum contribution to our defined benefit plans during the first quarter of fiscal 2016, nor do we anticipate making a contribution during the remainder of the fiscal year.

We contributed $5.5 million to our other post-retirement benefit plans during the three months ended December 31, 2015. We expect to contribute between $15 million and $25 million to these plans during fiscal 2016.