XML 42 R31.htm IDEA: XBRL DOCUMENT
v3.26.1

Employee and Retiree Benefit Plans (Tables) | 3 Months Ended
--- | ---
Mar. 31, 2026
Retirement Benefits [Abstract] |
Schedule of Components of Net Periodic Benefit Expense | The table that follows provides the components of net periodic benefit expense for the three-month periods ended March 31, 2026 and 2025.
| Three Months Ended March 31,
| Pension Benefits |  | Other Postretirement Benefits
(Thousands of dollars) | 2026 |  | 2025 |  | 2026 |  | 2025
Service cost | $ | 1,865 |  |  | $ | 1,683 |  |  | $ | 102 |  |  | $ | 84 |
Interest cost | 7,752 |  |  | 8,398 |  |  | 750 |  |  | 708 |
Expected return on plan assets | (8,792) |  |  | (8,871) |  |  | — |  |  | — |
Estimated defined contribution provision | 70 |  |  | 60 |  |  | — |  |  | — |
Amortization of prior service cost (credit) | 432 |  |  | 491 |  |  | (133) |  |  | (133) |
Recognized actuarial (gain) loss | 1,644 |  |  | 1,891 |  |  | (387) |  |  | (1,056) |
Total net periodic benefit cost (credit) | $ | 2,971 |  |  | $ | 3,652 |  |  | $ | 332 |  |  | $ | (397) |

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

X
- Definition Tabular disclosure of the components of net benefit costs for pension plans and/or other employee benefit plans including service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) recognized due to settlements or curtailments. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (q) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 715 -SubTopic 20 -Subparagraph (h) -Name Accounting Standards Codification -Paragraph 1 -Section 50 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 + Details
Name: | us-gaap_ScheduleOfNetBenefitCostsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration