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v3.20.4

Derivative Instruments - Cash Flow Hedges (Details) $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2020 USD ($) number_of_interest_rate_swaps | Dec. 31, 2019 USD ($) | Dec. 31, 2018 USD ($) | Jul. 12, 2018 number_of_interest_rate_swaps
Derivative instruments |  |  |  |
Total interest expense line item on the income statements | $ 493.7 | $ 501.5 | $ 445.1 |
Reclassification to interest expense within next twelve months | 5.5 |  |  |
WEC Energy Group |  |  |  |
Derivative instruments |  |  |  |
Total interest expense line item on the income statements | 96.9 | 122.3 | 104.1 |
WEC Energy Group | WEC Energy Group 2007 Junior Notes due 2067 |  |  |  |
Derivative instruments |  |  |  |
Long-term debt outstanding | $ 500.0 |  |  |
Interest rate swaps | WEC Energy Group |  |  |  |
Derivative instruments |  |  |  |
Number of interest rate swaps | number_of_interest_rate_swaps | 2 |  |  | 2
Interest rate swap notional value | $ 250.0 |  |  |
Interest rate swap fixed interest rate | 4.9765% |  |  |
Derivative loss recognized in other comprehensive loss | $ (5.9) | (4.8) | (2.9) |
Net derivative gain (loss) reclassified from accumulated other comprehensive loss to interest expense | $ (2.1) | $ 1.1 | $ 1.6 |

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