Schedule I - Fair Value Measurements (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Carrying amount
Notes to parent company financial statements
Long-term debt, including current portion	$ 15,464.2	$ 13,563.4
Fair value
Notes to parent company financial statements
Long-term debt, including current portion	13,921.3	14,819.4
Long-term debt, including current portion	15,464.2	13,563.4
WEC Energy Group \| Carrying amount
Notes to parent company financial statements
Long-term debt, including current portion	4,447.2	3,549.8
WEC Energy Group \| Fair value
Notes to parent company financial statements
Long-term debt, including current portion	$ 4,095.6	$ 3,546.9

Amount, excluding unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation.

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