Pension and Other Postretirement Benefits (Tables)

12 Months Ended

Dec. 31, 2015

Defined Benefit Plan Disclosure [Line Items]

Schedule of Defined Benefit Plans Disclosures

A reconciliation of the changes in Level 3 fair value measurements is as follows:

	Fixed Income - Corporate
PNMR Master Trust	PNM Pension			TNMP Pension			Total Master Trust
	(In thousands)
Balance at December 31, 2013	$	160		$	16		$	176
Actual return on assets sold during the period	—			—			—
Actual return on assets still held at period end	(18		)	(2		)	(20		)
Purchases	546			62			608
Sales	(33		)	(4		)	(37		)
Balance at December 31, 2014	655			72			727
Actual return on assets sold during the period	—			—			—
Actual return on assets still held at period end	(1		)	—			(1		)
Purchases	177			17			194
Sales	(112		)	(11		)	(123		)
Balance at December 31, 2015	$	719		$	78		$	797

Schedule of Health Care Cost Trend Rates

The following table shows the assumed health care cost trend rates for the PNM postretirement benefit plan:

	PNM Plan
	December 31,
	2015		2014
Health care cost trend rate assumed for next year	7.0	%	7.0	%
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)	5.0	%	5.0	%
Year that the rate reaches the ultimate trend rate	2024		2023

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

The following table shows the impact of a one-percentage-point change in assumed health care cost trend rates:

	PNM Plan
	1-Percentage- Point  Increase		1-Percentage- Point  Decrease
	(In thousands)
Effect on total of service and interest cost	$	273	$	(235	)
Effect on APBO	$	4,370	$	(3,840	)

Schedule of Net Funded Status

For the executive retirement programs, the following table presents information about the PBO and funded status of the plans:

	PNM Plan						TNMP Plan
	Year Ended December 31,						Year Ended December 31,
	2015			2014			2015			2014
	(In thousands)
PBO at beginning of year	$	17,730		$	16,363		$	878		$	823
Service cost	—			—			—			—
Interest cost	760			822			36			39
Actuarial (gain) loss	(908		)	2,040			(26		)	110
Benefits paid	(1,477		)	(1,495		)	(94		)	(94		)
PBO at end of year – funded status	16,105			17,730			794			878
Less current liability	1,519			1,528			93			94
Non-current liability	$	14,586		$	16,202		$	701		$	784

Summary of Expenses for Other Retirement Plans

A summary of expenses for these other retirement plans is as follows:

	Year Ended December 31,
	2015		2014		2013
	(In thousands)
PNMR
401(k) plan	$	16,725	$	16,703	$	16,785
Non-qualified plan	$	1,436	$	2,257	$	2,204
PNM
401(k) plan	$	12,679	$	12,745	$	12,952
Non-qualified plan	$	1,090	$	1,722	$	1,691
TNMP
401(k) plan	$	4,046	$	3,958	$	3,953
Non-qualified plan	$	346	$	535	$	513

Pension Plan [Member]

Defined Benefit Plan Disclosure [Line Items]

Schedule of Defined Benefit Plans Disclosures

The following table presents information about the PBO, fair value of plan assets, and funded status of the plans:

	PNM Plan						TNMP Plan
	Year Ended December 31,						Year Ended December 31,
	2015			2014			2015			2014
	(In thousands)
PBO at beginning of year	$	657,557		$	599,537		$	72,305		$	66,159
Service cost	—			—			—			—
Interest cost	28,255			30,163			3,043			3,193
Actuarial (gain) loss	(38,151		)	72,524			(5,157		)	8,466
Benefits paid	(49,761		)	(44,667		)	(5,993		)	(5,513		)
PBO at end of year	597,900			657,557			64,198			72,305
Fair value of plan assets at beginning of year	587,909			556,353			69,177			66,118
Actual return on plan assets	(10,225		)	76,223			(1,102		)	8,572
Employer contributions	30,000			—			—			—
Benefits paid	(49,761		)	(44,667		)	(5,993		)	(5,513		)
Fair value of plan assets at end of year	557,923			587,909			62,082			69,177
Funded status – asset (liability) for pension benefits	$	(39,977	)	$	(69,648	)	$	(2,116	)	$	(3,128	)

Schedule of Amounts in Accumulated Other Comprehensive Income (Loss) to be Recognized over Next Fiscal Year

The following table presents pre-tax information about prior service cost and net actuarial (gain) loss in AOCI as of December 31, 2015.

	PNM Plan						TNMP Plan
	December 31, 2015						December 31, 2015
	Prior service cost			Net actuarial (gain) loss			Net actuarial (gain) loss
	(In thousands)
Amounts in AOCI not yet recognized in net periodic benefit cost (income) at beginning of year	$	(2,260	)	$	148,212		$	—
Experience loss (gain)	—			11,397			365
Regulatory asset (liability) adjustment	—			(6,610		)	(365		)
Amortization recognized in net periodic benefit cost (income)	405			(6,224		)	—
Amounts in AOCI not yet recognized in net periodic benefit cost (income) at end of year	$	(1,855	)	$	146,775		$	—
Amortization expected to be recognized in 2016	$	(405	)	$	5,399		$	—

Schedule of Net Benefit Costs

The following table presents the components of net periodic benefit cost (income):

	Year Ended December 31,
	2015			2014			2013
	(In thousands)
PNM Plan
Service cost	$	—		$	—		$	—
Interest cost	28,255			30,163			28,142
Expected return on plan assets	(39,323		)	(38,044		)	(41,930		)
Amortization of net (gain) loss	14,820			13,020			14,840
Amortization of prior service cost	(965		)	(965		)	76
Net periodic benefit cost	$	2,787		$	4,174		$	1,128
TNMP Plan
Service cost	$	—		$	—		$	—
Interest cost	3,043			3,193			3,087
Expected return on plan assets	(4,420		)	(4,526		)	(4,849		)
Amortization of net (gain) loss	782			665			1,049
Amortization of prior service cost	—			—			—
Net periodic benefit cost (income)	$	(595	)	$	(668	)	$	(713	)

Schedule of Assumptions Used

The following significant weighted-average assumptions were used to determine the PBO and net periodic benefit cost (income). Should actual experience differ from actuarial assumptions, the PBO and net periodic benefit cost (income) would be affected.

	Year Ended December 31,
PNM Plan	2015		2014		2013
Discount rate for determining December 31 PBO	5.29	%	4.48	%	5.27	%
Discount rate for determining net periodic benefit cost (income)	4.48	%	5.27	%	4.30	%
Expected return on plan assets	6.80	%	7.20	%	7.65	%
Rate of compensation increase	N/A		N/A		N/A
TNMP Plan
Discount rate for determining December 31 PBO	5.39	%	4.39	%	5.06	%
Discount rate for determining net periodic benefit cost (income)	4.39	%	5.06	%	4.19	%
Expected return on plan assets	6.80	%	7.20	%	7.65	%
Rate of compensation increase	N/A		N/A		N/A

Schedule of Expected Benefit Payments

The following pension benefit payments are expected to be paid:

	PNM Plan		TNMP Plan
	(In thousands)
2016	$	49,963	$	5,800
2017	49,681		5,416
2018	48,209		5,697
2019	47,476		5,218
2020	46,474		4,955
2021 – 2025	213,810		23,401

Other Postretirement Benefits [Member]

Defined Benefit Plan Disclosure [Line Items]

Schedule of Defined Benefit Plans Disclosures

The following table presents information about the APBO, the fair value of plan assets, and the funded status of the plans:

	PNM Plan						TNMP Plan
	Year Ended December 31,						Year Ended December 31,
	2015			2014			2015			2014
	(In thousands)
APBO at beginning of year	$	95,175		$	92,165		$	14,070		$	12,266
Service cost	204			181			247			237
Interest cost	4,089			4,630			608			619
Participant contributions	2,439			2,582			320			366
Actuarial (gain) loss	(6,565		)	4,455			(575		)	1,639
Benefits paid	(10,668		)	(8,838		)	(1,564		)	(1,057		)
APBO at end of year	84,674			95,175			13,106			14,070
Fair value of plan assets at beginning of year	78,175			73,565			10,094			9,601
Actual return on plan assets	(617		)	7,334			(82		)	841
Employer contributions	3,623			3,532			343			343
Participant contributions	2,439			2,582			320			366
Benefits paid	(10,668		)	(8,838		)	(1,564		)	(1,057		)
Fair value of plan assets at end of year	72,952			78,175			9,111			10,094
Funded status – asset (liability)	$	(11,722	)	$	(17,000	)	$	(3,995	)	$	(3,976	)

Schedule of Net Benefit Costs

The following table presents the components of net periodic benefit cost:

	Year Ended December 31,
	2015			2014			2013
	(In thousands)
PNM Plan
Service cost	$	204		$	181		$	260
Interest cost	4,089			4,630			4,113
Expected return on plan assets	(5,610		)	(5,638		)	(5,043		)
Amortization of net (gain) loss	1,966			2,225			4,242
Amortization of prior service credit	(642		)	(1,343		)	(1,343		)
Net periodic benefit cost	$	7		$	55		$	2,229
TNMP Plan
Service cost	$	247		$	237		$	299
Interest cost	608			619			566
Expected return on plan assets	(520		)	(534		)	(503		)
Amortization of net (gain) loss	—			(122		)	—
Amortization of prior service cost	—			32			57
Net periodic benefit cost	$	335		$	232		$	419

Schedule of Assumptions Used

The following significant weighted-average assumptions were used to determine the APBO and net periodic benefit cost. Should actual experience differ from actuarial assumptions, the APBO and net periodic benefit cost would be affected.

	Year Ended December 31,
PNM Plan	2015		2014		2013
Discount rate for determining December 31 APBO	5.34	%	4.45	%	5.21	%
Discount rate for determining net periodic benefit cost	4.45	%	5.21	%	4.26	%
Expected return on plan assets	7.70	%	8.50	%	8.50	%
Rate of compensation increase	N/A		N/A		N/A
TNMP Plan
Discount rate for determining December 31 APBO	5.34	%	4.45	%	5.21	%
Discount rate for determining net periodic benefit cost	4.45	%	5.21	%	4.26	%
Expected return on plan assets	5.70	%	6.50	%	6.50	%
Rate of compensation increase	N/A		N/A		N/A

Schedule of Expected Benefit Payments

The following other postretirement benefit payments, which reflect expected future service and are net of participant contributions, are expected to be paid:

	PNM Plan		TNMP Plan
	(In thousands)
2016	$	6,568	$	838
2017	6,667		858
2018	6,815		880
2019	6,830		903
2020	6,875		927
2021 - 2025	33,268		4,939

Executive Retirement Program [Member]

Defined Benefit Plan Disclosure [Line Items]

Schedule of Amounts in Accumulated Other Comprehensive Income (Loss) to be Recognized over Next Fiscal Year

The following table presents pre-tax information about net actuarial loss in AOCI as of December 31, 2015.

	December 31, 2015
	PNM Plan			TNMP Plan
	(In thousands)
Amount in AOCI not yet recognized in net periodic benefit cost at beginning of year	$	2,602		$	—
Experience loss (gain)	(908		)	26
Regulatory asset (liability) adjustment	526			(26		)
Amortization recognized in net periodic benefit cost (income)	(136		)	—
Amount in AOCI not yet recognized in net periodic benefit cost at end of year	$	2,084		$	—
Amortization expected to be recognized in 2016	$	108		$	—

Schedule of Net Benefit Costs

The following table presents the components of net periodic benefit:

	Year Ended December 31,
	2015		2014		2013
	(In thousands)
PNM Plan
Service cost	$	—	$	—	$	—
Interest cost	760		822		720
Amortization of net (gain) loss	325		210		232
Amortization of prior service cost	—		—		—
Net periodic benefit cost	$	1,085	$	1,032	$	952
TNMP Plan
Service cost	$	—	$	—	$	—
Interest cost	36		39		36
Amortization of net (gain) loss	5		—		—
Amortization of prior service cost	—		—		—
Net periodic benefit cost	$	41	$	39	$	36

Schedule of Assumptions Used

The following significant weighted-average assumptions were used to determine the PBO and net periodic benefit cost. Should actual experience differ from actuarial assumptions, the PBO and net periodic benefit cost would be affected.

	Year Ended December 31,
PNM Plan	2015		2014		2013
Discount rate for determining December 31 PBO	5.29	%	4.48	%	5.27	%
Discount rate for determining net periodic benefit cost	4.48	%	5.27	%	4.30	%
Long-term rate of return on plan assets	N/A		N/A		N/A
Rate of compensation increase	N/A		N/A		N/A
TNMP Plan
Discount rate for determining December 31 PBO	5.39	%	4.39	%	5.06	%
Discount rate for determining net periodic benefit cost	4.39	%	5.06	%	4.19	%
Long-term rate of return on plan assets	N/A		N/A		N/A
Rate of compensation increase	N/A		N/A		N/A

Schedule of Expected Benefit Payments

The following executive retirement plan payments, which reflect expected future service, are expected:

	PNM Plan		TNMP Plan
	(In thousands)
2016	$	1,517	$	93
2017	1,499		92
2018	1,477		90
2019	1,453		88
2020	1,426		85
2021 – 2025	6,587		371