Income Taxes (Tables)

12 Months Ended

Sep. 30, 2023

Income Tax Disclosure [Abstract]

Schedule of Income Tax Expense from Continuing Operations

The components of income tax expense from continuing operations for 2023, 2022 and 2021 were as follows:

	2023		2022		2021
	(In thousands)
Current
Federal	$	(1,274)	$	2,849	$	—
State	13,550		28,125		252
Deferred
Federal	83,244		43,435		128,867
State	18,259		3,101		24,617
Income tax expense	$	113,779	$	77,510	$	153,736

Schedule of Effective Income Tax Rate Reconciliation

Reconciliations of the provision for income taxes computed at the statutory rate of 21 percent to the reported provisions for income taxes from continuing operations for 2023, 2022 and 2021 are set forth below:

	2023		2022		2021
	(In thousands)
Tax at statutory rate	$	209,925	$	178,901	$	172,053
Common stock dividends deductible for tax reporting	(1,355)		(1,355)		(1,372)
State taxes (net of federal benefit)	25,129		24,669		19,647
Amortization of excess deferred taxes	(123,953)		(127,193)		(45,382)
Other, net	4,033		2,488		8,790
Income tax expense	$	113,779	$	77,510	$	153,736

Schedule of Deferred Tax Assets and Liabilities

The tax effect of temporary differences that gave rise to significant components of the deferred tax liabilities and deferred tax assets at September 30, 2023 and 2022 are presented below:

	2023		2022
	(In thousands)
Deferred tax assets:
Employee benefit plans	$	50,576	$	57,094
Net operating loss carryforwards	504,121		485,061
Charitable and other credit carryforwards	10,084		1,903
Regulatory excess deferred tax	76,943		110,548
Lease asset	58,633		50,007
Other	42,257		44,035
Total deferred tax assets	742,614		748,648
Valuation allowance	(351)		(523)
Net deferred tax assets	742,263		748,125
Deferred tax liabilities:
Difference in net book value and net tax value of assets	(2,674,341)		(2,431,757)
Gas cost adjustments	(47,822)		(43,964)
Winter Storm Uri regulatory asset	(28,116)		(20,710)
Lease liability	(51,666)		(50,007)
Rate deferral adjustment	(47,218)		(49,309)
Interest rate agreements	(149,969)		(106,820)
Other	(48,105)		(45,063)
Total deferred tax liabilities	(3,047,237)		(2,747,630)
Net deferred tax liabilities	$	(2,304,974)	$	(1,999,505)

Schedule of Unrecognized Tax Benefits

The following table reconciles the beginning and ending balance of our unrecognized tax benefits:

	2023		2022		2021
	(In thousands)
Unrecognized tax benefits - beginning balance	$	52,683	$	32,792	$	30,921
Increase (decrease) resulting from prior period tax positions	(631)		(721)		671
Increase resulting from current period tax positions	6,586		20,612		1,200
Unrecognized tax benefits - ending balance	58,638		52,683		32,792
Less: deferred federal and state income tax benefits	(12,314)		(11,063)		(6,886)
Total unrecognized tax benefits that, if recognized, would impact the effective income tax rate as of the end of the year	$	46,324	$	41,620	$	25,906