Income Taxes (Tables)

12 Months Ended

Sep. 30, 2023

Income Tax Disclosure [Abstract]

Components of Federal and State Income Taxes Included in the Consolidated Statements of Income

The components of federal and state income taxes included in the Consolidated Statements of Income are as follows:

	Year Ended September 30
	2023		2022		2021
	(Thousands)
Current Income Taxes —
Federal	$	11,744	$	—	$	(10)
State	1,386		12,214		8,699
Deferred Income Taxes —
Federal	106,801		137,025		90,970
State	44,602		(32,610)		15,023
Total Income Taxes	$	164,533	$	116,629	$	114,682

Schedule of Income Tax Reconciliation by Applying Federal Income Tax Rate

The following is a reconciliation of this difference:

	Year Ended September 30
	2023		2022		2021
	(Thousands)
U.S. Income Before Income Taxes	$	641,399	$	682,650	$	478,329
Income Tax Expense, Computed at U.S. Federal Statutory Rate of 21%	$	134,694	$	143,357	$	100,449
State Valuation Allowance (1)	—		(24,850)		(5,560)
State Income Taxes (2)	36,331		8,736		24,300
Amortization of Excess Deferred Federal Income Taxes	(6,053)		(5,184)		(5,215)
Plant Flow Through Items	(2,856)		(814)		(1,503)
Stock Compensation	957		820		2,239
Federal Tax Credits	(6)		(5,701)		(310)
Miscellaneous	1,466		265		282
Total Income Taxes	$	164,533	$	116,629	$	114,682

(1)During fiscal 2022, the valuation allowance recorded against certain state deferred tax assets was removed. See discussion below.

(2)The state income tax expense shown above includes adjustments to the estimated state effective tax rates utilized in the calculation of deferred income taxes, including the Pennsylvania rate change discussed above.

Significant Components of Deferred Tax Liabilities and Assets

Significant components of the Company’s deferred tax liabilities and assets were as follows:

	At September 30
	2023		2022
	(Thousands)
Deferred Tax Liabilities:
Unrealized Hedging Gains	$	3,385	$	—
Property, Plant and Equipment	1,178,893		954,757
Pension and Other Post-Retirement Benefit Costs	44,358		30,132
Other	21,470		48,893
Total Deferred Tax Liabilities	1,248,106		1,033,782
Deferred Tax Assets:
Unrealized Hedging Losses	—		(215,187)
Tax Loss and Credit Carryforwards	(33,744)		(50,686)
Pension and Other Post-Retirement Benefit Costs	(41,843)		(37,250)
Other	(48,349)		(32,430)
Total Deferred Tax Assets	(123,936)		(335,553)
Total Net Deferred Income Taxes	$	1,124,170	$	698,229

Summary of Changes in Valuation Allowances for Deferred Tax Assets

The following is a summary of changes in valuation allowances for deferred tax assets:

	Year Ended September 30
	2023		2022		2021
	(Thousands)
Balance at Beginning of Year	$	—	$	57,645	$	63,205
Additions	—		—		—
Deductions	—		57,645		5,560
Balance at End of Year	$	—	$	—	$	57,645

Summary of Operating Loss and Tax Credit Carryforwards

Tax carryforwards available, prior to valuation allowance, at September 30, 2023, were as follows:

Jurisdiction	Tax Attribute	Amount (Thousands)		Expires
Pennsylvania	Net Operating Loss	$	404,403	2031-2043
Federal	General Business Credits	$	1,819	2042