RETIREMENT BENEFITS AND ASSETS HELD IN TRUST (Tables)

12 Months Ended

Dec. 31, 2015

Retirement Plan

Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block

Plan Assets By Category

The plan assets of the retirement plan consisted of the following assets by category:

Asset Category	2015		2014
Fixed income securities	50.4	%	48.8	%
Equity securities	49.6	%	51.2	%
Total	100.0	%	100.0	%

Assets Measured at Fair Value Subject to Three-Tier Hierarchy

The fair value measurement of the retirement plan assets as of December 31, 2015, was as follows:

	Fair Value Measurements at Reporting Date Using
	Quoted Prices in		Significant		Significant
	Active Markets for		Other Observable		Unobservable
(In thousands)	Identical Assets		Inputs		Inputs
	(Level 1)		(Level 2)		(Level 3)
Financial assets measured on a recurring basis:
Mutual funds — U.S. equity securities	$	23,427	$	—	$	—
Mutual funds — international equity securities	5,409		—		—
Mutual funds — fixed income securities	29,291		—		—
Total	$	58,127	$	—	$	—

The fair value measurement of the retirement plan assets as of December 31, 2014, was as follows:

	Fair Value Measurements at Reporting Date Using
	Quoted Prices in		Significant		Significant
	Active Markets for		Other Observable		Unobservable
(In thousands)	Identical Assets		Inputs		Inputs
	(Level 1)		(Level 2)		(Level 3)
Financial assets measured on a recurring basis:
Mutual funds — U.S. equity securities	$	23,770	$	—	$	—
Mutual funds — international equity securities	5,096		—		—
Mutual funds — fixed income securities	23,783		—		—
Guaranteed deposit fund	—		3,741		—
Total	$	52,649	$	3,741	$	—

Defined Benefit Plans

Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block

Net Defined Benefit Cost Components

Net periodic benefit cost for the pension plans during 2015, 2014 and 2013 was as follows by component:

(In thousands)	2015			2014			2013
Service cost	$	6,496		$	5,066		$	5,261
Interest cost	3,696			3,603			2,792
Expected return on plan assets	(3,838		)	(3,541		)	(2,868		)
Amortization of prior service credit	(42		)	(42		)	(42		)
Amortization of unrecognized loss	4,243			1,545			2,714
Net pension cost	$	10,555		$	6,631		$	7,857

Defined Benefit Plans Disclosures

The following table reconciles the obligations, assets and funded status of the pension plans as well as the presentation of the funded status of the pension plans in the consolidated statements of financial position as of December 31, 2015 and 2014:

(In thousands)	2015			2014
Change in Benefit Obligation:
Beginning projected benefit obligation	$	(95,740	)	$	(73,468	)
Service cost	(6,496		)	(5,066		)
Interest cost	(3,696		)	(3,603		)
Actuarial net gain (loss)	5,869			(14,937		)
Benefits paid	2,747			1,334
Other	128			—
Ending projected benefit obligation	$	(97,188	)	$	(95,740	)
Change in Plan Assets:
Beginning plan assets at fair value	$	56,390		$	48,894
Actual return on plan assets	(129		)	4,851
Employer contributions	4,102			3,822
Benefits paid	(2,108		)	(1,177		)
Other	(128		)	—
Ending plan assets at fair value	$	58,127		$	56,390
Funded status, underfunded	$	(39,061	)	$	(39,350	)
Accumulated benefit obligation:
Retirement plan	$	(49,169	)	$	(48,571	)
Supplemental benefit plans	(40,830		)	(35,962		)
Total accumulated benefit obligation	$	(89,999	)	$	(84,533	)
Amounts recorded as:
Funded Status:
Accrued pension liabilities	$	(45,322	)	$	(44,033	)
Other non-current assets	6,408			4,683
Other current liabilities	(147		)	—
Total	$	(39,061	)	$	(39,350	)
Unrecognized Amounts in Non-current Regulatory Assets:
Net actuarial loss	$	18,724		$	24,868
Prior service credit	66			25
Total	$	18,790		$	24,893

Assumptions Used

Actuarial assumptions used to determine the benefit obligation for the pension plans at December 31, 2015, 2014 and 2013 are as follows:

	2015	2014	2013
Discount rate	4.01 - 4.44%	3.75 - 4.05%	4.60 - 5.10%
Annual rate of salary increases	4.00%	4.00%	4.00 - 6.00%

Actuarial assumptions used to determine the benefit cost for the pension plans for the years ended December 31, 2015, 2014 and 2013 are as follows:

	2015	2014	2013
Discount rate	3.75 - 4.05%	4.60 - 5.10%	3.70 - 4.45%
Annual rate of salary increases	4.00%	4.00 - 6.00%	5.00 - 6.00%
Expected long-term rate of return on plan assets	6.70%	6.75%	7.00%

Projected Benefit Payments

At December 31, 2015, the projected benefit payments for the pension plans calculated using the same assumptions as those used to calculate the benefit obligation described above are as follows:

(In thousands)
2016	$	1,716
2017	5,259
2018	5,548
2019	5,878
2020	6,551
2021 through 2025	38,681

Other Postretirement Benefits Plan

Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block

Plan Assets By Category

The plan assets consisted of the following assets by category:

Asset Category	2015		2014
Fixed income securities	50.0	%	57.2	%
Equity securities	50.0	%	42.8	%
Total	100.0	%	100.0	%

Net Defined Benefit Cost Components

Net postretirement benefit plan cost for 2015, 2014 and 2013 was as follows by component:

(In thousands)	2015			2014			2013
Service cost	$	8,486		$	5,846		$	5,774
Interest cost	2,477			1,991			1,562
Expected return on plan assets	(1,852		)	(1,361		)	(1,415		)
Amortization of unrecognized loss	499			—			220
Net postretirement cost	$	9,610		$	6,476		$	6,141

Defined Benefit Plans Disclosures

The following table reconciles the obligations, assets and funded status of the plan as well as the amounts recognized as accrued postretirement liability in the consolidated statements of financial position as of December 31, 2015 and 2014:

(In thousands)	2015			2014
Change in Benefit Obligation:
Beginning accumulated postretirement obligation	$	(57,927	)	$	(42,706	)
Service cost	(8,486		)	(5,846		)
Interest cost	(2,477		)	(1,991		)
Actuarial net gain (loss)	10,265			(7,695		)
Benefits paid	662			311
Other	8			—
Ending accumulated postretirement obligation	$	(57,955	)	$	(57,927	)
Change in Plan Assets:
Beginning plan assets at fair value	$	32,397		$	24,004
Actual return on plan assets	155			2,107
Employer contributions	9,122			6,286
Employer provided retiree premiums	662			311
Benefits paid	(662		)	(311		)
Other	(6		)	—
Ending plan assets at fair value	$	41,668		$	32,397
Funded status, underfunded	$	(16,287	)	$	(25,530	)
Amounts recorded as:
Funded Status:
Accrued postretirement liabilities	$	(16,287	)	$	(25,530	)
Total	$	(16,287	)	$	(25,530	)
Unrecognized Amounts in Non-current Regulatory Assets:
Net actuarial loss	$	191		$	9,258
Total	$	191		$	9,258

Assumptions Used

Actuarial assumptions used to determine the benefit obligation at December 31, 2015, 2014 and 2013 are as follows:

	2015	2014	2013
Discount rate	4.62%	4.20%	5.15%
Annual rate of salary increases	4.00%	4.00%	4.00%
Health care cost trend rate assumed for next year	7.15%	7.25%	7.50%
Rate to which the cost trend rate is assumed to decline	5.00%	5.00%	5.00%
Year that the rate reaches the ultimate trend rate	2022	2022	2022
Annual rate of increase in dental benefit costs	5.00%	5.00%	5.00%

Actuarial assumptions used to determine the benefit cost for the years ended December 31, 2015, 2014 and 2013 are as follows:

	2015	2014	2013
Discount rate	4.20%	5.15%	4.20%
Annual rate of salary increases	4.00%	4.00%	5.00%
Health care cost trend rate assumed for next year	7.25%	7.50%	8.00%
Rate to which the cost trend rate is assumed to decline	5.00%	5.00%	5.00%
Year that the rate reaches the ultimate trend rate	2022	2022	2017
Expected long-term rate of return on plan assets	5.20%	5.50%	7.00%

Projected Benefit Payments

At December 31, 2015, the projected benefit payments for the postretirement benefit plan calculated using the same assumptions as those used to calculate the benefit obligations listed above are as follows:

(In thousands)
2016	$	636
2017	734
2018	967
2019	1,241
2020	1,603
2021 through 2025	13,245

Assets Measured at Fair Value Subject to Three-Tier Hierarchy

The fair value measurement of the other postretirement benefit plan assets as of December 31, 2015, was as follows:

	Fair Value Measurements at Reporting Date Using
	Quoted Prices in		Significant		Significant
	Active Markets for		Other Observable		Unobservable
(In thousands)	Identical Assets		Inputs		Inputs
	(Level 1)		(Level 2)		(Level 3)
Financial assets measured on a recurring basis:
Cash and cash equivalents	$	30	$	—	$	—
Mutual funds — U.S. equity securities	19,981		—		—
Mutual funds — international equity securities	863		—		—
Mutual funds — fixed income securities	20,794		—		—
Total	$	41,668	$	—	$	—

The fair value measurement of the other postretirement benefit plan assets as of December 31, 2014, was as follows:

	Fair Value Measurements at Reporting Date Using
	Quoted Prices in		Significant		Significant
	Active Markets for		Other Observable		Unobservable
(In thousands)	Identical Assets		Inputs		Inputs
	(Level 1)		(Level 2)		(Level 3)
Financial assets measured on a recurring basis:
Cash and cash equivalents	$	5,099	$	—	$	—
Mutual funds — U.S. equity securities	13,070		—		—
Mutual funds — international equity securities	785		—		—
Mutual funds — fixed income securities	12,790		—		—
Guaranteed deposit fund	—		653		—
Total	$	31,744	$	653	$	—

Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates

A one-percentage-point increase or decrease in assumed health care cost trend rates would have the following effects on costs for 2015 and the postretirement benefit obligation at December 31, 2015:

	One-Percentage-		One-Percentage-
(In thousands)	Point Increase		Point Decrease
Effect on total of service and interest cost	$	3,288	$	(2,282	)
Effect on postretirement benefit obligation	13,452		(9,869		)