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Schedule I - Short-Term Notes Payable to Related Parties (Details) - WEC Energy Group - USD ($) $ in Millions | Dec. 31, 2017 | Dec. 31, 2016
--- | --- | ---
Notes to parent company financial statements |  |
Short-term notes payable to related parties | $ 406.0 | $ 241.3
Integrys |  |
Notes to parent company financial statements |  |
Short-term notes payable to related parties | 278.2 | 0.0
WECC |  |
Notes to parent company financial statements |  |
Short-term notes payable to related parties | 110.2 | 109.3
WBS |  |
Notes to parent company financial statements |  |
Short-term notes payable to related parties | 16.4 | 131.1
Wisvest |  |
Notes to parent company financial statements |  |
Short-term notes payable to related parties | 0.9 | 0.9
Bluewater Gas Storage, LLC |  |
Notes to parent company financial statements |  |
Short-term notes payable to related parties | $ 0.3 | $ 0.0

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