Pension and Other Postretirement Benefit Plans (Tables)

3 Months Ended

Mar. 31, 2021

Retirement Benefits [Abstract]

Schedule of Net Benefit Costs

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

	Three Months Ended March 31,
	Pension Plan				OPEB Plan				Executive Retirement Program
	2021		2020		2021		2020		2021		2020
	(In thousands)
Components of Net Periodic Benefit Cost
Service cost	$	—	$	—	$	6	$	10	$	—	$	—
Interest cost	4,036		4,985		477		613		90		122
Expected return on plan assets	(7,133)		(7,363)		(1,042)		(1,387)		—		—
Amortization of net loss	4,541		4,465		—		87		100		101
Amortization of prior service cost	—		(138)		—		—		—		—
Net Periodic Benefit Cost (Income)	$	1,444	$	1,949	$	(559)	$	(677)	$	190	$	223

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

	Three Months Ended March 31,
	Pension Plan				OPEB Plan				Executive Retirement Program
	2021		2020		2021		2020		2021		2020
	(In thousands)
Components of Net Periodic Benefit Cost
Service cost	$	—	$	—	$	11	$	12	$	—	$	—
Interest cost	435		544		77		93		4		6
Expected return on plan assets	(795)		(821)		(102)		(134)		—		—
Amortization of net (gain) loss	312		315		(80)		(81)		9		6
Amortization of prior service cost	—		—		—		—		—		—
Net Periodic Benefit Cost (Income)	$	(48)	$	38	$	(94)	$	(110)	$	13	$	12