XML 26 R16.htm IDEA: XBRL DOCUMENT
v3.25.1

Interim Pension and Other Postretirement Benefit Plan Information | 6 Months Ended
--- | ---
Mar. 31, 2025
Retirement Benefits, Description [Abstract] |
Interim Pension and Other Postretirement Benefit Plan Information | Interim Pension and Other Postretirement Benefit Plan Information The components of our net periodic pension cost for our pension and other postretirement benefit plans for the three and six months ended March 31, 2025 and 2024 are presented in the following tables. Most of these costs are recoverable through our tariff rates. A portion of these costs is capitalized into our rate base or deferred as a regulatory asset or liability. The remaining costs are recorded as a component of operation and maintenance expense or other non-operating expense.
| Three Months Ended March 31
| Pension Benefits |  | Other Benefits
| 2025 |  | 2024 |  | 2025 |  | 2024
| (In thousands)
Components of net periodic pension cost: |  |  |  |  |  |  |
Service cost | $ | 2,837 |  |  | $ | 2,405 |  |  | $ | 2,033 |  |  | $ | 1,507 |
Interest cost (1) | 6,663 |  |  | 7,430 |  |  | 3,365 |  |  | 3,509 |
Expected return on assets (1) | (7,655) |  |  | (7,202) |  |  | (3,831) |  |  | (3,128) |
Amortization of prior service cost (credit) (1) | — |  |  | — |  |  | (3,260) |  |  | (3,260) |
Amortization of actuarial (gain) loss (1) | 256 |  |  | 97 |  |  | (2,429) |  |  | (2,718) |
Net periodic pension cost | $ | 2,101 |  |  | $ | 2,730 |  |  | $ | (4,122) |  |  | $ | (4,090) |
| Six Months Ended March 31
| Pension Benefits |  | Other Benefits
| 2025 |  | 2024 |  | 2025 |  | 2024
| (In thousands)
Components of net periodic pension cost: |  |  |  |  |  |  |
Service cost | $ | 5,674 |  |  | $ | 4,794 |  |  | $ | 4,066 |  |  | $ | 3,014 |
Interest cost (1) | 13,326 |  |  | 14,926 |  |  | 6,731 |  |  | 7,017 |
Expected return on assets (1) | (15,309) |  |  | (14,404) |  |  | (7,663) |  |  | (6,256) |
Amortization of prior service cost (credit) (1) | — |  |  | — |  |  | (6,520) |  |  | (6,520) |
Amortization of actuarial (gain) loss (1) | 511 |  |  | 215 |  |  | (4,858) |  |  | (5,436) |
Settlements (1) | — |  |  | 776 |  |  | — |  |  | — |
Net periodic pension cost | $ | 4,202 |  |  | $ | 6,307 |  |  | $ | (8,244) |  |  | $ | (8,181) |
(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, 2024.

X
- References No definition available. + Details
Name: | us-gaap_GeneralDiscussionOfPensionAndOtherPostretirementBenefitsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The entire disclosure for retirement benefits. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 70 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480794/715-70-50-1 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 17 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480482/715-20-55-17 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(03) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (q) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (l) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -Name Accounting Standards Codification -Publisher FASB -URI https://asc.fasb.org/715/tableOfContent Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(iii) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (o) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 Reference 10: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (p) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 Reference 11: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (r)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 Reference 12: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (r)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 Reference 13: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section S99 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480126/715-20-S99-2 Reference 14: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 60 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480266/715-60-50-3 + Details
Name: | us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration