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Financing: Long-Term Debt (Details) - USD ($) $ in Millions | Dec. 31, 2023 | Dec. 31, 2022
--- | --- | ---
Debt Instrument [Line Items] |  |
Total long-term debt | $ 4,426.0 | $ 4,154.6
Less current maturities | (600.0) | (525.0)
Less unamortized deferred financing costs | (24.8) | (22.3)
Long-term debt, net of current maturities | 3,801.2 | 3,607.3
Revolving Credit Facility |  |
Debt Instrument [Line Items] |  |
Less unamortized deferred financing costs | (1.1) | (1.8)
Black Hills Corporation | Corporate, Non-Segment |  |
Debt Instrument [Line Items] |  |
Long-term debt | 3,900.0 | 3,625.0
Less unamortized debt discount | (8.9) | (5.3)
Total long-term debt | $ 3,891.1 | 3,619.7
Black Hills Corporation | Corporate, Non-Segment | Senior Unsecured Notes Due 2023 |  |
Debt Instrument [Line Items] |  |
Long-term debt |  | 525.0
Black Hills Corporation | Corporate, Non-Segment | Senior Unsecured Notes Due 2024 |  |
Debt Instrument [Line Items] |  |
Stated interest rate (percent) | 1.04% |
Long-term debt | $ 600.0 | 600.0
Black Hills Corporation | Corporate, Non-Segment | Senior Unsecured Notes Due 2026 |  |
Debt Instrument [Line Items] |  |
Stated interest rate (percent) | 3.95% |
Long-term debt | $ 300.0 | 300.0
Black Hills Corporation | Corporate, Non-Segment | Senior Unsecured Notes Due 2027 |  |
Debt Instrument [Line Items] |  |
Stated interest rate (percent) | 3.15% |
Long-term debt | $ 400.0 | 400.0
Black Hills Corporation | Corporate, Non-Segment | Senior Unsecured Notes Due 2028 |  |
Debt Instrument [Line Items] |  |
Stated interest rate (percent) | 5.95% |
Long-term debt | $ 350.0 |
Black Hills Corporation | Corporate, Non-Segment | Senior Unsecured Notes Due 2029 |  |
Debt Instrument [Line Items] |  |
Stated interest rate (percent) | 3.05% |
Long-term debt | $ 400.0 | 400.0
Black Hills Corporation | Corporate, Non-Segment | Senior Unsecured Notes Due 2030 |  |
Debt Instrument [Line Items] |  |
Stated interest rate (percent) | 2.50% |
Long-term debt | $ 400.0 | 400.0
Black Hills Corporation | Corporate, Non-Segment | Senior Unsecured Notes Due 2033 |  |
Debt Instrument [Line Items] |  |
Stated interest rate (percent) | 4.35% |
Long-term debt | $ 400.0 | 400.0
Black Hills Corporation | Corporate, Non-Segment | Senior Unsecured Notes Due 2034 |  |
Debt Instrument [Line Items] |  |
Stated interest rate (percent) | 6.15% |
Long-term debt | $ 450.0 |
Black Hills Corporation | Corporate, Non-Segment | Senior Unsecured Notes Due 2046 |  |
Debt Instrument [Line Items] |  |
Stated interest rate (percent) | 4.20% |
Long-term debt | $ 300.0 | 300.0
Black Hills Corporation | Corporate, Non-Segment | Senior Unsecured Notes Due 2049 |  |
Debt Instrument [Line Items] |  |
Stated interest rate (percent) | 3.88% |
Long-term debt | $ 300.0 | 300.0
Black Hills Energy - South Dakota Electric | Electric Utilities |  |
Debt Instrument [Line Items] |  |
Long-term debt | 340.0 | 340.0
Less unamortized debt discount | (0.1) | (0.1)
Total long-term debt | $ 339.9 | 339.9
Black Hills Energy - South Dakota Electric | Electric Utilities | First Mortgage Bonds Due 2032 |  |
Debt Instrument [Line Items] |  |
Stated interest rate (percent) | 7.23% |
Long-term debt | $ 75.0 | 75.0
Black Hills Energy - South Dakota Electric | Electric Utilities | First Mortgage Bonds Due 2039 |  |
Debt Instrument [Line Items] |  |
Stated interest rate (percent) | 6.13% |
Long-term debt | $ 180.0 | 180.0
Black Hills Energy - South Dakota Electric | Electric Utilities | First Mortgage Bonds Due 2044 |  |
Debt Instrument [Line Items] |  |
Stated interest rate (percent) | 4.43% |
Long-term debt | $ 85.0 | 85.0
Wyoming Electric | Electric Utilities |  |
Debt Instrument [Line Items] |  |
Long-term debt | 195.0 | 195.0
Total long-term debt | 195.0 | 195.0
Wyoming Electric | Electric Utilities | Senior Unsecured Notes Due 2027 |  |
Debt Instrument [Line Items] |  |
Long-term debt | $ 10.0 |
Wyoming Electric | Electric Utilities | First Mortgage Bonds Due 2044 |  |
Debt Instrument [Line Items] |  |
Stated interest rate (percent) | 4.53% |
Long-term debt | $ 75.0 | 75.0
Wyoming Electric | Electric Utilities | Industrial Development Revenue Bonds Due 2027 |  |
Debt Instrument [Line Items] |  |
Variable interest rate (percent) | 3.93% |
Long-term debt | $ 10.0 | 10.0
Wyoming Electric | Electric Utilities | First Mortgage Bonds Due 2037 |  |
Debt Instrument [Line Items] |  |
Stated interest rate (percent) | 6.67% |
Long-term debt | $ 110.0 | $ 110.0

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