Pension and Other Postretirement Benefit Plans (Tables)

9 Months Ended

Sep. 30, 2017

Retirement Benefits [Abstract]

Schedule of Net Benefit Costs

The following tables present the components of the PNM Plans’ net periodic benefit cost:

	Three Months Ended September 30,
	Pension Plan						OPEB Plan						Executive Retirement Program
	2017			2016			2017			2016			2017		2016
	(In thousands)
Components of Net Periodic Benefit Cost
Service cost	$	—		$	—		$	24		$	35		$	—	$	—
Interest cost	6,727			7,577			1,006			1,087			174		203
Expected return on plan assets	(8,451		)	(8,854		)	(1,308		)	(1,371		)	—		—
Amortization of net (gain) loss	4,001			3,455			921			286			78		64
Amortization of prior service cost	(241		)	(241		)	(416		)	(7		)	—		—
Net periodic benefit cost	$	2,036		$	1,937		$	227		$	30		$	252	$	267

	Nine Months Ended September 30,
	Pension Plan						OPEB Plan						Executive Retirement Program
	2017			2016			2017			2016			2017		2016
	(In thousands)
Components of Net Periodic Benefit Cost
Service cost	$	—		$	—		$	72		$	105		$	—	$	—
Interest cost	20,181			22,731			3,019			3,260			523		609
Expected return on plan assets	(25,352		)	(26,562		)	(3,923		)	(4,113		)	—		—
Amortization of net (gain) loss	12,004			10,365			2,762			858			235		192
Amortization of prior service cost	(724		)	(724		)	(1,248		)	(22		)	—		—
Net periodic benefit cost	$	6,109		$	5,810		$	682		$	88		$	758	$	801

The following tables present the components of the TNMP Plans’ net periodic benefit cost:

	Three Months Ended September 30,
	Pension Plan						OPEB Plan						Executive Retirement Program
	2017			2016			2017			2016			2017		2016
	(In thousands)
Components of Net Periodic Benefit Cost
Service cost	$	—		$	—		$	36		$	46		$	—	$	—
Interest cost	722			826			139			169			8		10
Expected return on plan assets	(945		)	(986		)	(114		)	(122		)	—		—
Amortization of net (gain) loss	231			175			(20		)	(10		)	2		1
Amortization of prior service cost	—			—			—			—			—		—
Net Periodic Benefit Cost	$	8		$	15		$	41		$	83		$	10	$	11

	Nine Months Ended September 30,
	Pension Plan						OPEB Plan						Executive Retirement Program
	2017			2016			2017			2016			2017		2016
	(In thousands)
Components of Net Periodic Benefit Cost
Service cost	$	—		$	—		$	107		$	139		$	—	$	—
Interest cost	2,165			2,478			417			508			25		30
Expected return on plan assets	(2,834		)	(2,957		)	(342		)	(367		)	—		—
Amortization of net (gain) loss	692			525			(60		)	(30		)	7		1
Amortization of prior service cost	—			—			—			—			—		—
Net Periodic Benefit Cost	$	23		$	46		$	122		$	250		$	32	$	31