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Income Taxes - Effective Income Tax Rate (Details) | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2022 | Sep. 30, 2021 | Sep. 30, 2022 | Sep. 30, 2021
Income Tax Disclosure [Abstract] |  |  |  |
Federal Statutory Rate | 21.00% | 21.00% | 21.00% | 21.00%
Increases (Decreases) in Tax from: |  |  |  |
State Taxes on Income, Net of Federal Tax | 5.00% | 5.00% | 5.00% | 5.00%
Production Tax Credits (PTCs) | (3.60%) | (5.00%) | (4.10%) | (6.00%)
Amortization of Excess Deferred Income Taxes | (0.90%) | (1.60%) | (0.70%) | (2.00%)
North Dakota Wind Tax Credit Amortization, Net of Federal Tax | (0.10%) | (0.20%) | (0.20%) | (0.30%)
Corporate-Owned Life Insurance | 0.20% | (0.30%) | 0.40% | (0.60%)
Other, Net | (0.50%) | (0.60%) | 0.10% | (0.20%)
Effective Tax Rate | 21.10% | 18.30% | 21.50% | 16.90%

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