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Regulatory Matters | 3 Months Ended
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Mar. 31, 2025
Regulatory Assets and Liabilities Disclosure [Abstract] |
Regulatory Matters | Regulatory Matters Regulatory Assets and Liabilities The following presents our current and long-term regulatory assets and liabilities as of March 31, 2025 and December 31, 2024 and the period we expect to recover or refund such amounts:
| Period of |  | March 31, 2025 |  | December 31, 2024
(in thousands) | Recovery/Refund |  | Current |  | Long-Term |  | Current |  | Long-Term
Regulatory Assets |  |  |  |  |  |  |  |  |
Pension and Other Postretirement Benefit Plans 1 | Various |  | $ | — |  |  | $ | 87,834 |  |  | $ | — |  |  | $ | 88,161 |
Alternative Revenue Program Riders 2 | Up to 2 years |  | 4,226 |  |  | 244 |  |  | 4,257 |  |  | 195 |
Deferred Income Taxes 1 | Asset lives |  | — |  |  | 9,053 |  |  | — |  |  | 8,944 |
Fuel Clause Adjustments 1 | Up to 1 year |  | 5,418 |  |  | — |  |  | 2,218 |  |  | — |
Derivative Instruments 1 | Up to 2 years |  | 632 |  |  | 1,052 |  |  | 1,989 |  |  | — |
Other 1 | Various |  | 1,263 |  |  | 1,241 |  |  | 1,498 |  |  | 1,373 |
Total Regulatory Assets |  |  | $ | 11,539 |  |  | $ | 99,424 |  |  | $ | 9,962 |  |  | $ | 98,673 |
Regulatory Liabilities |  |  |  |  |  |  |  |  |
Deferred Income Taxes | Asset lives |  | $ | — |  |  | $ | 128,495 |  |  | $ | — |  |  | $ | 130,387 |
Plant Removal Obligations | Asset lives |  | — |  |  | 126,579 |  |  | — |  |  | 126,263 |
Fuel Clause Adjustments | Up to 1 year |  | 7,169 |  |  | — |  |  | 11,432 |  |  | — |
Alternative Revenue Program Riders | Up to 1 year |  | 14,917 |  |  | — |  |  | 14,255 |  |  | — |
North Dakota PTC Refunds | Asset lives |  | — |  |  | 23,816 |  |  | — |  |  | 20,099 |
Pension and Other Postretirement Benefit Plans | Various |  | 2,547 |  |  | 10,153 |  |  | 2,547 |  |  | 10,758 |
Other | Various |  | 2,395 |  |  | 1,635 |  |  | 1,073 |  |  | 1,421 |
Total Regulatory Liabilities |  |  | $ | 27,028 |  |  | $ | 290,678 |  |  | $ | 29,307 |  |  | $ | 288,928 |
1 Costs subject to recovery without a rate of return. |  |  |  |  |  |  |  |  |
2 Amounts eligible for recovery includes an incentive or rate of return. |  |  |  |  |  |  |  |

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- Definition The entire disclosure for detailed information about regulatory assets and liabilities, including current and noncurrent assets created when regulatory agencies permit the deferral of costs to the balance sheet that would otherwise be required to appear on the company's income statement and would be charged against current expenses or revenues, as well as current and noncurrent liabilities created when regulatory agencies permit. + References No definition available. + Details
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