Regulation (Tables)

12 Months Ended

Sep. 30, 2024

Regulated Operations [Abstract]

Schedule of Regulatory Assets

Significant regulatory assets and liabilities as of September 30, 2024 and 2023 included the following:

	September 30
	2024		2023
	(In thousands)
Regulatory assets:
Pension and postretirement benefit costs	$	11,243	$	20,629
Infrastructure mechanisms (1)	246,734		229,996
Winter Storm Uri incremental costs	10,373		32,115
Deferred gas costs	159,762		148,297
Regulatory excess deferred taxes (2)	51,380		47,549
Recoverable loss on reacquired debt	3,070		3,238
Deferred pipeline record collection costs	41,742		54,008
APT annual System Safety and Integrity Rider (3)	38,632		—
Other	16,454		19,096
	$	579,390	$	554,928
Regulatory liabilities:
Regulatory excess deferred taxes (2)	$	257,001	$	384,513
Regulatory cost of removal obligation	607,032		582,867
Deferred gas costs	9,142		23,093
APT annual adjustment mechanism	73,119		49,894
Pension and postretirement benefit costs	247,250		215,913
Other	34,338		28,054
	$	1,227,882	$	1,284,334

(1)Infrastructure mechanisms in Texas, Louisiana, and Tennessee allow for the deferral of all eligible expenses associated with capital expenditures incurred pursuant to these rules, including the recording of interest on the deferred expenses until the next rate proceeding (rate case or annual rate filing), at which time investment and costs would be recovered through base rates.

(2)Regulatory excess deferred taxes represent changes in our net deferred tax liability related to our cost of service ratemaking due to the enactment of the Tax Cuts and Jobs Act of 2017 (the "TCJA") and a Kansas legislative change enacted in fiscal 2020. See Notes 13 and 15 to the consolidated financial statements for further information.

(3)In APT's general rate case settlement in December 2023, the RRC approved a new annual compliance filing that allows APT to recover certain system safety and integrity costs incurred each year. Costs above a specified benchmark are deferred onto the balance sheet as incurred. Once the filing is approved by the RRC, the revenue and expense are recognized over 12 months resulting in no impact to operating income.

Schedule of Regulatory Liabilities

Significant regulatory assets and liabilities as of September 30, 2024 and 2023 included the following:

	September 30
	2024		2023
	(In thousands)
Regulatory assets:
Pension and postretirement benefit costs	$	11,243	$	20,629
Infrastructure mechanisms (1)	246,734		229,996
Winter Storm Uri incremental costs	10,373		32,115
Deferred gas costs	159,762		148,297
Regulatory excess deferred taxes (2)	51,380		47,549
Recoverable loss on reacquired debt	3,070		3,238
Deferred pipeline record collection costs	41,742		54,008
APT annual System Safety and Integrity Rider (3)	38,632		—
Other	16,454		19,096
	$	579,390	$	554,928
Regulatory liabilities:
Regulatory excess deferred taxes (2)	$	257,001	$	384,513
Regulatory cost of removal obligation	607,032		582,867
Deferred gas costs	9,142		23,093
APT annual adjustment mechanism	73,119		49,894
Pension and postretirement benefit costs	247,250		215,913
Other	34,338		28,054
	$	1,227,882	$	1,284,334

(1)Infrastructure mechanisms in Texas, Louisiana, and Tennessee allow for the deferral of all eligible expenses associated with capital expenditures incurred pursuant to these rules, including the recording of interest on the deferred expenses until the next rate proceeding (rate case or annual rate filing), at which time investment and costs would be recovered through base rates.

(2)Regulatory excess deferred taxes represent changes in our net deferred tax liability related to our cost of service ratemaking due to the enactment of the Tax Cuts and Jobs Act of 2017 (the "TCJA") and a Kansas legislative change enacted in fiscal 2020. See Notes 13 and 15 to the consolidated financial statements for further information.

(3)In APT's general rate case settlement in December 2023, the RRC approved a new annual compliance filing that allows APT to recover certain system safety and integrity costs incurred each year. Costs above a specified benchmark are deferred onto the balance sheet as incurred. Once the filing is approved by the RRC, the revenue and expense are recognized over 12 months resulting in no impact to operating income.