Regulation (Tables)

6 Months Ended

Mar. 31, 2025

Regulated Operations [Abstract]

Schedule of Regulatory Assets

Regulatory assets and liabilities as of March 31, 2025 and September 30, 2024 included the following:

	March 31, 2025		September 30, 2024
	(In thousands)
Regulatory assets:
Pension and postretirement benefit costs	$	4,326	$	11,243
Infrastructure mechanisms (1)	239,997		246,734
Winter Storm Uri incremental costs	6,812		10,373
Deferred gas costs	3,830		159,762
Regulatory excess deferred taxes (2)	50,526		51,380
Recoverable loss on reacquired debt	2,987		3,070
Deferred pipeline record collection costs	39,899		41,742
APT annual System Safety and Integrity Rider (3)	34,142		38,632
Other	16,270		16,454
	$	398,789	$	579,390
Regulatory liabilities:
Regulatory excess deferred taxes (2)	$	229,096	$	257,001
Regulatory cost of removal obligation	625,899		607,032
Deferred gas costs	54,794		9,142
APT annual adjustment mechanism	78,126		73,119
Pension and postretirement benefit costs	236,382		247,250
Other	51,006		34,338
	$	1,275,303	$	1,227,882

(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 deferred expenses until the next rate proceeding (rate case or annual rate filing), at which time investment and costs would be recoverable 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 Tax Cuts and Jobs Act of 2017 (the "TCJA"), a Kansas legislative change enacted in fiscal 2020, and a Louisiana legislative change enacted in fiscal 2025. See Note 12 to the condensed 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

Regulatory assets and liabilities as of March 31, 2025 and September 30, 2024 included the following:

	March 31, 2025		September 30, 2024
	(In thousands)
Regulatory assets:
Pension and postretirement benefit costs	$	4,326	$	11,243
Infrastructure mechanisms (1)	239,997		246,734
Winter Storm Uri incremental costs	6,812		10,373
Deferred gas costs	3,830		159,762
Regulatory excess deferred taxes (2)	50,526		51,380
Recoverable loss on reacquired debt	2,987		3,070
Deferred pipeline record collection costs	39,899		41,742
APT annual System Safety and Integrity Rider (3)	34,142		38,632
Other	16,270		16,454
	$	398,789	$	579,390
Regulatory liabilities:
Regulatory excess deferred taxes (2)	$	229,096	$	257,001
Regulatory cost of removal obligation	625,899		607,032
Deferred gas costs	54,794		9,142
APT annual adjustment mechanism	78,126		73,119
Pension and postretirement benefit costs	236,382		247,250
Other	51,006		34,338
	$	1,275,303	$	1,227,882

(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 deferred expenses until the next rate proceeding (rate case or annual rate filing), at which time investment and costs would be recoverable 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 Tax Cuts and Jobs Act of 2017 (the "TCJA"), a Kansas legislative change enacted in fiscal 2020, and a Louisiana legislative change enacted in fiscal 2025. See Note 12 to the condensed 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.