Schedule I - Balance Sheets (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Assets
Cash and cash equivalents	$ 182.2	$ 87.5	$ 72.6	$ 82.3
Current assets
Prepaid income taxes	201.8	182.1
Other	261.7	253.4
Current assets	3,187.7	2,656.7
Long-term assets
Other	427.3	361.1
Long-term assets	38,684.4	36,331.8
Total assets	41,872.1	38,988.5	37,028.1
Current liabilities
Current portion of long-term debt	808.5	91.0
Other	884.6	680.9
Current liabilities	4,611.0	3,753.0
Long-term liabilities
Long-term debt	14,655.7	13,472.4
Other	1,475.3	1,203.2
Long-term liabilities	25,644.5	24,122.2
Equity
Total liabilities and equity	41,872.1	38,988.5
WEC Energy Group
Assets
Cash and cash equivalents	0.0	0.5	$ 4.0	$ 0.5
Current assets
Accounts receivable from related parties	0.7	0.6
Notes receivable from related parties	30.9	29.0
Prepaid income taxes	35.4	56.5
Other	0.1	0.1
Current assets	67.1	86.7
Long-term assets
Investments in subsidiaries	16,533.4	15,365.4
Other	24.2	21.8
Long-term assets	16,557.6	15,387.2
Total assets	16,624.7	15,473.9
Current liabilities
Short-term debt	399.7	736.1
Current portion of long-term debt	700.0	0.0
Accounts payable to related parties	2.0	5.5
Notes payable to related parties	332.5	220.4
Other	31.8	21.5
Current liabilities	1,466.0	983.5
Long-term liabilities
Long-term debt	3,747.2	3,549.8
Other	34.6	27.4
Long-term liabilities	3,781.8	3,577.2
Equity
Common shareholders' equity	11,376.9	10,913.2
Total liabilities and equity	$ 16,624.7	$ 15,473.9