Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Accounts receivable and unbilled revenues, reserves	$ 162.8	$ 193.5
Property, plant, and equipment, accumulated depreciation and amortization	$ 11,611.9	$ 11,073.1
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	650,000,000	650,000,000
Common stock, shares outstanding	317,680,855	315,434,531
Balance sheets
Regulatory assets (December 31, 2024 and December 31, 2023 include $76.5 and $85.9, respectively, related to WEPCo Environmental Trust)	$ 3,339.7	$ 3,249.8
Current portion of long-term debt (December 31, 2024 and December 31, 2023 include $9.2 and $9.0, respectively, related to WEPCo Environmental Trust)	1,729.0	1,264.2
Long-term debt (December 31, 2024 and December 31, 2023 include $76.4 and $85.3, respectively, related to WEPCo Environmental Trust)	17,178.1	15,366.9
WEPCo Environmental Trust
Balance sheets
Regulatory assets (December 31, 2024 and December 31, 2023 include $76.5 and $85.9, respectively, related to WEPCo Environmental Trust)	76.5	85.9
Current portion of long-term debt (December 31, 2024 and December 31, 2023 include $9.2 and $9.0, respectively, related to WEPCo Environmental Trust)	9.2	9.0
Long-term debt (December 31, 2024 and December 31, 2023 include $76.4 and $85.3, respectively, related to WEPCo Environmental Trust)	$ 76.4	$ 85.3

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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