Interim Pension and Other Postretirement Benefit Plan Information (Tables)

3 Months Ended

Dec. 31, 2023

Retirement Benefits, Description [Abstract]

Schedule of Net Benefit Costs

	Three Months Ended December 31
	Pension Benefits				Other Benefits
	2023		2022		2023		2022
	(In thousands)
Components of net periodic pension cost:
Service cost	$	2,389	$	2,908	$	1,507	$	1,546
Interest cost (1)	7,497		7,325		3,509		3,478
Expected return on assets (1)	(7,202)		(7,278)		(3,128)		(2,804)
Amortization of prior service cost (credit) (1)	—		(30)		(3,260)		(3,285)
Amortization of actuarial (gain) loss (1)	118		164		(2,718)		(1,863)
Settlements (1)	776		—		—		—
Net periodic pension cost	$	3,578	$	3,089	$	(4,090)	$	(2,928)

(1)    The components of net periodic cost other than the service cost component are included in the line item other non-operating expense in the condensed consolidated statements of comprehensive income or are capitalized on the condensed consolidated balance sheets as a regulatory asset or liability, as described in Note 2 to the consolidated financial statements in our Annual Report on Form 10-K for the fiscal year ended September 30, 2023.