CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Statement of Financial Position [Abstract]
Accounts receivable and unbilled revenues, reserves	$ 142.2	$ 162.8
Property, plant, and equipment, accumulated depreciation and amortization	$ 12,025.9	$ 11,611.9
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	650,000,000	650,000,000
Common stock, shares outstanding	321,866,395	317,680,855
Regulatory assets (June 30, 2025 and December 31, 2024 include $72.2 and $76.5, respectively, related to WEPCo Environmental Trust)	$ 3,231.8	$ 3,339.7
Current portion of long-term debt (June 30, 2025 and December 31, 2024 include $9.2, related to WEPCo Environmental Trust)	2,250.4	1,729.0
Long-term debt (June 30, 2025 and December 31, 2024 include $71.9 and $76.4, respectively, related to WEPCo Environmental Trust)	17,110.4	17,178.1
WEPCo Environmental Trust
Regulatory assets (June 30, 2025 and December 31, 2024 include $72.2 and $76.5, respectively, related to WEPCo Environmental Trust)	72.2	76.5
Current portion of long-term debt (June 30, 2025 and December 31, 2024 include $9.2, related to WEPCo Environmental Trust)	9.2	9.2
Long-term debt (June 30, 2025 and December 31, 2024 include $71.9 and $76.4, respectively, related to WEPCo Environmental Trust)	$ 71.9	$ 76.4

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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