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Schedule I - Long-Term Debt (Details) - USD ($) $ in Millions | Dec. 31, 2018 | Dec. 31, 2017
--- | --- | ---
Future maturities of long-term debt outstanding |  |
2020 | $ 686.9 |
2021 | 1,338.8 |
Thereafter | 7,918.2 |
Total | 10,387.6 |
WEC Energy Group |  |
Future maturities of long-term debt outstanding |  |
2020 | 400.0 |
2021 | 600.0 |
Thereafter | 1,200.0 |
Total | 2,200.0 |
Long-term notes outstanding | 2,190.8 | $ 1,592.3
WEC Energy Group | WECC | Support agreement related to WECC debt |  |
Future maturities of long-term debt outstanding |  |
Long-term notes outstanding | $ 50.0 |

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