Schedule I - Short-Term Notes Payable to Related Parties (Details) - WEC Energy Group - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Notes to parent company financial statements
Short-term notes payable to related parties	$ 303.0	$ 489.3
WBS
Notes to parent company financial statements
Short-term notes payable to related parties	149.0	168.9
WECC
Notes to parent company financial statements
Short-term notes payable to related parties	110.0	111.7
Bluewater Gas Storage
Notes to parent company financial statements
Short-term notes payable to related parties	44.0	41.8
Integrys
Notes to parent company financial statements
Short-term notes payable to related parties	$ 0.0	$ 166.9

The amount for notes payable (written promise to pay), due to related parties. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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