Schedule I - Statements of Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Operating activities
Net income attributed to common shareholders	$ 1,527.2	$ 1,331.7	$ 1,408.1
Reconciliation to cash provided by operating activities
Equity income in subsidiaries, net of distributions	(57.4)	(33.0)	(74.3)
Deferred income taxes, net	538.7	229.9	278.5
Gain on debt extinguishments	(23.1)	(0.5)	0.0
Change in -
Other current assets	(75.4)	36.3	32.3
Other current liabilities	11.6	47.5	126.9
Other, net	(34.8)	(156.5)	(169.5)
Net cash provided by operating activities	3,211.8	3,018.4	2,060.7
Investing activities
Capital contributions to subsidiaries	(45.5)	(63.7)	(45.5)
Other, net	10.1	(21.9)	(10.6)
Net cash used in investing activities	(3,802.5)	(3,558.2)	(2,642.4)
Financing activities
Exercise of stock options	23.7	6.3	33.6
Issuance of common stock, net	163.4	0.0	0.0
Purchase of common stock	(3.2)	(16.6)	(69.2)
Dividends paid on common stock	(1,056.2)	(984.2)	(917.9)
Issuance of long-term debt	4,460.9	2,170.0	1,999.3
Retirement of long-term debt	(2,138.0)	(1,005.4)	(92.1)
Change in commercial paper	(902.8)	373.7	(252.6)
Payments for debt extinguishment and issuance costs	(45.9)	(14.2)	(15.6)
Other, net	(6.1)	(6.8)	(9.1)
Net cash provided by financing activities	467.7	522.8	676.4
Net change in cash, cash equivalents, and restricted cash	(123.0)	(17.0)	94.7
Cash, cash equivalents, and restricted cash at beginning of year	165.2	182.2	87.5
Cash, cash equivalents, and restricted cash at end of year	42.2	165.2	182.2
WEC Energy Group
Operating activities
Net income attributed to common shareholders	1,527.2	1,331.7	1,408.1
Reconciliation to cash provided by operating activities
Equity income in subsidiaries, net of distributions	(931.8)	(566.8)	(437.4)
Deferred income taxes, net	(2.1)	(3.8)	11.6
Gain on debt extinguishments	(23.1)	0.0	0.0
Change in -
Accounts receivable from related parties	0.0	(2.0)	(0.1)
Prepaid income taxes	(16.3)	35.4	21.1
Other current assets	0.2	(0.1)	0.0
Accounts payable to related parties	0.2	0.9	(3.5)
Accrued interest	(3.6)	42.1	15.4
Other current liabilities	(0.6)	(0.7)	(5.1)
Other, net	15.5	14.4	5.8
Net cash provided by operating activities	565.6	851.1	1,015.9
Investing activities
Capital contributions to subsidiaries	(1,273.9)	(1,807.4)	(1,099.7)
Return of capital from subsidiaries	846.6	175.2	372.9
Short-term notes receivable from related parties, net	(47.2)	14.9	(1.9)
Other, net	0.0	0.0	(2.0)
Net cash used in investing activities	(474.5)	(1,617.3)	(730.7)
Financing activities
Exercise of stock options	23.7	6.3	33.6
Issuance of common stock, net	163.4	0.0	0.0
Purchase of common stock	(3.2)	(16.6)	(69.2)
Dividends paid on common stock	(1,056.2)	(984.2)	(917.9)
Issuance of long-term debt	2,475.0	2,050.0	900.0
Retirement of long-term debt	(1,473.7)	(700.0)	0.0
Change in commercial paper	(314.3)	297.3	(336.4)
Short-term notes payable to related parties, net	121.3	127.1	112.1
Payments for debt extinguishment and issuance costs	(27.0)	(13.3)	(6.7)
Other, net	(0.1)	(0.4)	(1.2)
Net cash provided by financing activities	(91.1)	766.2	(285.7)
Net change in cash, cash equivalents, and restricted cash	0.0	0.0	(0.5)
Cash, cash equivalents, and restricted cash at beginning of year	0.0	0.0	0.5
Cash, cash equivalents, and restricted cash at end of year	$ 0.0	$ 0.0	$ 0.0