Employee benefit plans

6 Months Ended

Jun. 30, 2024

Retirement Benefits [Abstract]

Employee benefit plans

Employee benefit plans

Pension and other postretirement plans

The Company has noncontributory qualified defined benefit pension plans and other postretirement benefit plans for certain eligible employees.

Components of net periodic benefit cost (credit) for the Company's pension benefit plans were as follows:

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2024		2023		2024		2023
	(In thousands)
Components of net periodic benefit cost (credit):
Interest cost	$	3,200	$	3,380	$	6,400	$	7,169
Expected return on assets	(4,028)		(4,299)		(8,056)		(9,048)
Amortization of net actuarial loss	1,037		773		2,074		1,674
Net periodic benefit cost (credit)	$	209	$	(146)	$	418	$	(205)

Components of net periodic benefit credit for the Company's other postretirement benefit plans were as follows:

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2024		2023		2024		2023
	(In thousands)
Components of net periodic benefit credit:
Service cost	$	126	$	136	$	252	$	274
Interest cost	459		489		918		978
Expected return on assets	(1,329)		(1,334)		(2,658)		(2,668)
Amortization of prior service credit	(330)		(329)		(660)		(659)
Amortization of net actuarial gain	(72)		(70)		(144)		(126)
Net periodic benefit credit, including amount capitalized	(1,146)		(1,108)		(2,292)		(2,201)
Less amount capitalized	47		53		69		77
Net periodic benefit credit	$	(1,193)	$	(1,161)	$	(2,361)	$	(2,278)

The components of net periodic benefit cost (credit), other than the service cost component, are included in Other income on the Consolidated Statements of Income. The service cost component is included in Operation and maintenance expense on the Consolidated Statements of Income.

Nonqualified defined benefit plans

In addition to the qualified defined benefit pension plans reflected in the table at the beginning of this note, the Company also has unfunded, nonqualified defined benefit plans for executive officers and certain key management employees. The Company's net periodic benefit cost for these plans was $733,000 and $750,000 for the three months ended June 30, 2024 and 2023, respectively, and $1.5 million for both of the six months ended June 30, 2024 and 2023. The components of net periodic benefit cost for these plans are included in Other income on the Consolidated Statements of Income.