Retirement and Post-Retirement Employee Benefit Plans (Table)

12 Months Ended

Sep. 30, 2015

Compensation and Retirement Disclosure [Abstract]

Schedule of Net Periodic Benefit Cost Not Yet Recognized And Recorded as Regulatory Assets

The amounts that have not yet been recognized in net periodic pension cost that have been recorded as regulatory assets are as follows:

	Defined Benefits Plans			Supplemental Executive Retirement Plans		Postretirement Plans			Total
	(In thousands)
September 30, 2015
Unrecognized transition obligation	$	—		$	—	$	82		$	82
Unrecognized prior service credit	(1,735		)	—		(4,524		)	(6,259		)
Unrecognized actuarial loss	120,948			36,915		(47,149		)	110,714
	$	119,213		$	36,915	$	(51,591	)	$	104,537
September 30, 2014
Unrecognized transition obligation	$	—		$	—	$	354		$	354
Unrecognized prior service credit	(1,927		)	—		(6,168		)	(8,095		)
Unrecognized actuarial loss	109,767			34,447		7,531			151,745
	$	107,840		$	34,447	$	1,717		$	144,004

Schedule of Allocation of Plan Assets

The following table presents asset allocation information for the Master Trust as of September 30, 2015 and 2014.

	Targeted Allocation  Range	Actual Allocation September 30
Security Class		2015		2014
Domestic equities	35%-55%	41.3	%	44.9	%
International equities	10%-20%	14.9	%	15.3	%
Fixed income	5%-30%	11.0	%	9.7	%
Company stock	0%-15%	15.2	%	12.9	%
Other assets	0%-20%	17.6	%	17.2	%

The following table presents asset allocation information for the postretirement benefit plan assets as of September 30, 2015 and 2014.

	Actual Allocation September 30
Security Class	2015		2014
Diversified investment funds	97.5	%	99.7	%
Cash and cash equivalents	2.5	%	0.3	%

Schedule of Employee Pension Plans Investments at Fair Value

In addition to the assets shown below, the Master Trust had net accounts receivable of $2.4 million and $2.7 million at September 30, 2015 and 2014 which materially approximates fair value due to the short-term nature of these assets.

	Assets at Fair Value as of September 30, 2015
	Level 1		Level 2		Level 3		Total
	(In thousands)
Investments:
Common stocks	$	159,304	$	—	$	—	$	159,304
Money market funds	—		11,787		—		11,787
Registered investment companies:
Domestic funds	33,312		—		—		33,312
International funds	48,648		—		—		48,648
Common/collective trusts — domestic funds	—		93,081		—		93,081
Government securities:
Mortgage-backed securities	—		14,359		—		14,359
U.S. treasuries	5,279		805		—		6,084
Corporate bonds	—		28,973		—		28,973
Limited partnerships	—		52,996		—		52,996
Total investments at fair value	$	246,543	$	202,001	$	—	$	448,544

	Assets at Fair Value as of September 30, 2014
	Level 1		Level 2		Level 3		Total
	(In thousands)
Investments:
Common stocks	$	155,107	$	—	$	—	$	155,107
Money market funds	—		11,226		—		11,226
Registered investment companies:
Domestic funds	33,266		—		—		33,266
International funds	48,134		—		—		48,134
Common/collective trusts — domestic funds	—		91,792		—		91,792
Government securities:
Mortgage-backed securities	—		12,520		—		12,520
U.S. treasuries	3,117		562		—		3,679
Corporate bonds	—		25,734		—		25,734
Limited partnerships	—		50,496		—		50,496
Real estate	—		—		155		155
Total investments at fair value	$	239,624	$	192,330	$	155	$	432,109

Schedule of Expected Benefit Payments

The following benefit payments paid by us, retirees and prescription drug subsidy payments for our postretirement benefit plans, which reflect expected future service, as appropriate, are expected to be paid in the following fiscal years. Company payments for fiscal 2015 include contributions to our postretirement plan trusts.

	Company Payments		Retiree Payments		Subsidy Payments		Total Postretirement Benefits
	(In thousands)
2016	$	15,498	$	2,382	$	—	$	17,880
2017	11,245		2,677		—		13,922
2018	12,185		2,980		—		15,165
2019	12,755		3,324		—		16,079
2020	13,995		3,766		—		17,761
2021-2025	86,519		26,363		—		112,882

The following benefit payments for our defined benefit plans, which reflect expected future service, as appropriate, are expected to be paid in the following fiscal years:

	Pension Plans		Supplemental Plans
	(In thousands)
2016	$	30,909	$	21,857
2017	31,805		13,901
2018	33,086		12,807
2019	34,712		6,808
2020	36,128		4,454
2021-2025	201,857		47,047

Schedule of Postretirement Benefit Plans Investments at Fair Value

	Assets at Fair Value as of September 30, 2015
	Level 1		Level 2		Level 3		Total
	(In thousands)
Investments:
Money market funds	$	—	$	3,486	$	—	$	3,486
Registered investment companies:
Domestic funds	123,921		—		—		123,921
International funds	10,602		—		—		10,602
Total investments at fair value	$	134,523	$	3,486	$	—	$	138,009

	Assets at Fair Value as of September 30, 2014
	Level 1		Level 2		Level 3		Total
	(In thousands)
Investments:
Money market funds	$	—	$	434	$	—	$	434
Registered investment companies:
Domestic funds	124,006		—		—		124,006
International funds	10,381		—		—		10,381
Total investments at fair value	$	134,387	$	434	$	—	$	134,821

Schedule of Assumptions Used [Table Text Block]

Additional assumptions are presented in the following table:

	Pension Liability				Pension Cost
	2015		2014		2015		2014		2013
Discount rate	4.55	%	4.43	%	4.43	%	4.95	%	4.04	%
Rate of compensation increase	3.50	%	3.50	%	3.50	%	3.50	%	3.50	%
Expected return on plan assets	7.00	%	7.25	%	7.25	%	7.25	%	7.75	%

The actuarial assumptions used to determine the pension liability for the supplemental plans were determined as of September 30, 2015 and 2014 and the actuarial assumptions used to determine the net periodic pension cost for the supplemental plans were determined as of September 30, 2014, 2013 and 2012. These assumptions are presented in the following table:

	Pension Liability				Pension Cost
	2015		2014		2015		2014		2013
Discount rate	4.55	%	4.43	%	4.43	%	4.95	%	4.04	%	(1)
Rate of compensation increase	3.50	%	3.50	%	3.50	%	3.50	%	3.50	%

⁽¹⁾ The discount rate for the supplemental plans increased from 4.04% to 4.21% effective April 1, 2013 due to a settlement loss recorded in fiscal 2013.

The actuarial assumptions used to determine the pension liability for our postretirement plan were determined as of September 30, 2015 and 2014 and the actuarial assumptions used to determine the net periodic pension cost for the postretirement plan were determined as of September 30, 2014, 2013 and 2012. The assumptions are presented in the following table:

	Postretirement Liability				Postretirement Cost
	2015		2014		2015		2014		2013
Discount rate	4.55	%	4.43	%	4.43	%	4.95	%	4.04	%
Expected return on plan assets	4.45	%	4.60	%	4.60	%	4.60	%	4.70	%
Initial trend rate	7.50	%	7.50	%	7.50	%	8.00	%	8.00	%
Ultimate trend rate	5.00	%	5.00	%	5.00	%	5.00	%	5.00	%
Ultimate trend reached in	2021		2020		2020		2020		2019

Changes in Projected Benefit Obligations, Fair Value of Plan Assets, and Funded Status of Plan [Table Text Block]

The following table presents the Plans’ accumulated benefit obligation, projected benefit obligation and funded status as of September 30, 2015 and 2014:

	2015			2014
	(In thousands)
Accumulated benefit obligation	$	485,921		$	466,182
Change in projected benefit obligation:
Benefit obligation at beginning of year	$	493,594		$	455,799
Service cost	16,231			15,345
Interest cost	21,850			22,330
Actuarial (gain) loss	7,420			26,611
Benefits paid	(30,496		)	(24,519		)
Plan amendments	—			(1,972		)
Benefit obligation at end of year	508,599			493,594
Change in plan assets:
Fair value of plan assets at beginning of year	434,767			396,887
Actual return on plan assets	8,661			35,289
Employer contributions	38,000			27,110
Benefits paid	(30,496		)	(24,519		)
Fair value of plan assets at end of year	450,932			434,767
Reconciliation:
Funded status	(57,667		)	(58,827		)
Unrecognized prior service cost	—			—
Unrecognized net loss	—			—
Net amount recognized	$	(57,667	)	$	(58,827	)

The following table presents the supplemental plans’ accumulated benefit obligation, projected benefit obligation and funded status as of September 30, 2015 and 2014:

	2015			2014
	(In thousands)
Accumulated benefit obligation	$	118,835		$	106,276
Change in projected benefit obligation:
Benefit obligation at beginning of year	$	113,219		$	117,080
Service cost	3,971			3,607
Interest cost	4,943			4,966
Actuarial (gain) loss	4,811			9,468
Benefits paid	(4,551		)	(5,085		)
Settlements	—			(16,817		)
Benefit obligation at end of year	122,393			113,219
Change in plan assets:
Fair value of plan assets at beginning of year	—			—
Employer contribution	4,551			21,902
Benefits paid	(4,551		)	(5,085		)
Settlements	—			(16,817		)
Fair value of plan assets at end of year	—			—
Reconciliation:
Funded status	(122,393		)	(113,219		)
Unrecognized prior service cost	—			—
Unrecognized net loss	—			—
Accrued pension cost	$	(122,393	)	$	(113,219	)

The following table presents the postretirement plan’s benefit obligation and funded status as of September 30, 2015 and 2014:

	2015			2014
	(In thousands)
Change in benefit obligation:
Benefit obligation at beginning of year	$	315,118		$	312,148
Service cost	15,583			16,784
Interest cost	14,385			15,951
Plan participants’ contributions	4,563			4,435
Actuarial (gain) loss	(69,962		)	(18,963		)
Benefits paid	(12,508		)	(13,580		)
Plan amendments	—			(1,657		)
Benefit obligation at end of year	267,179			315,118
Change in plan assets:
Fair value of plan assets at beginning of year	134,821			106,413
Actual return on plan assets	(8,851		)	14,003
Employer contributions	19,984			23,550
Plan participants’ contributions	4,563			4,435
Benefits paid	(12,508		)	(13,580		)
Fair value of plan assets at end of year	138,009			134,821
Reconciliation:
Funded status	(129,170		)	(180,297		)
Unrecognized transition obligation	—			—
Unrecognized prior service cost	—			—
Unrecognized net loss	—			—
Accrued postretirement cost	$	(129,170	)	$	(180,297	)

Schedule of Net Benefit Costs [Table Text Block]

Net periodic postretirement cost for fiscal 2015, 2014 and 2013 is recorded as operating expense and included the components presented below.

	Fiscal Year Ended September 30
	2015			2014			2013
	(In thousands)
Components of net periodic postretirement cost:
Service cost	$	15,583		$	16,784		$	18,800
Interest cost	14,385			15,951			12,964
Expected return on assets	(6,431		)	(5,167		)	(3,988		)
Amortization of transition obligation	272			274			1,081
Amortization of prior service credit	(1,644		)	(1,450		)	(1,450		)
Recognized actuarial loss	—			631			4,196
Net periodic postretirement cost	$	22,165		$	27,023		$	31,603

Net periodic pension cost for the Plans for fiscal 2015, 2014 and 2013 is recorded as operating expense and included the following components:

	Fiscal Year Ended September 30
	2015			2014			2013
	(In thousands)
Components of net periodic pension cost:
Service cost	$	16,231		$	15,345		$	17,754
Interest cost	21,850			22,330			19,334
Expected return on assets	(25,744		)	(23,601		)	(22,955		)
Amortization of prior service credit	(192		)	(136		)	(141		)
Recognized actuarial loss	13,322			13,777			19,066
Net periodic pension cost	$	25,467		$	27,715		$	33,058

Net periodic pension cost for the supplemental plans for fiscal 2015, 2014 and 2013 is recorded as operating expense and included the following components:

	Fiscal Year Ended September 30
	2015		2014		2013
	(In thousands)
Components of net periodic pension cost:
Service cost	$	3,971	$	3,607	$	3,039
Interest cost	4,943		4,966		4,755
Amortization of transition asset	—		—		—
Amortization of prior service cost	—		—		—
Recognized actuarial loss	2,343		1,948		2,918
Settlements	—		4,539		3,160
Net periodic pension cost	$	11,257	$	15,060	$	13,872

Schedule of Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates [Table Text Block]

Assumed health care cost trend rates have a significant effect on the amounts reported for the plan. A one-percentage point change in assumed health care cost trend rates would have the following effects on the latest actuarial calculations:

	One-Percentage Point Increase		One-Percentage Point Decrease
	(In thousands)
Effect on total service and interest cost components	$	4,288	$	(3,426	)
Effect on postretirement benefit obligation	$	39,572	$	(32,440	)