Commitments and Contingencies - Environmental Matters (Details) $ in Millions	1 Months Ended					12 Months Ended
	May 31, 2024 MMBTU performance_obligations	Feb. 29, 2024 micrograms	Aug. 31, 2023	May 31, 2021	Dec. 31, 2020 micrograms	Dec. 31, 2024 USD ($) MW	Nov. 30, 2024	Dec. 31, 2023 USD ($)	Nov. 30, 2023 Years
Manufactured Gas Plant Remediation
Regulatory asset						$ 3,378.7		$ 3,274.7
Estimated future cash expenditures for environmental remediation						445.8		463.7
Environmental remediation costs
Manufactured Gas Plant Remediation
Regulatory asset						570.1		596.8
Estimated future cash expenditures for environmental remediation						$ 445.8
Cross State Air Pollution Rule | Electric | Maximum
Air Quality
RICE unit megawatts | MW						25
Mercury and Air Toxics Standards | Electric
Air Quality
Current level of particulate matter in pounds per million british thermal unit | MMBTU	0.03
EPA new lower limit for particulate matter | MMBTU	0.01
National Ambient Air Quality Standards | Electric
Air Quality
Current level of micrograms per cubic meter that particulate matter needs to be below | micrograms					12
Current level of micrograms per cubic meter under 24-hour standard that particulate matter needs to be below | micrograms					35
New primary annual PM2.5 level | micrograms		9
National Ambient Air Quality Standards | Electric | Minimum
Air Quality
Period of time for EPA review of ozone plan			3 years
Number of years between evaluation of attainment status			3 years
National Ambient Air Quality Standards | Electric | Maximum
Air Quality
Period of time for EPA review of ozone plan			5 years
Climate Change | Electric
Air Quality
Number of applicable GHG performance standards for coal plants | performance_obligations	0
Percent capacity factor that if combined cycle natural gas plants are above it the rule is dependent upon the implementation of carbon capture by the end of 2031	40.00%
Number of applicable GHG performance standards for new simple cycle natural gas-fired combustion turbines | performance_obligations	0
Percent capacity factor for simple cycle natural gas fired combustion turbines that there are no applicable limits if the capacity factor is less than this	20.00%
Capacity of fossil-fueled generation retired, in megawatts | MW						2,500
Capacity of coal-fired generation to be retired by the end of 2031, in megawatts | MW						1,200
Company goal for percentage of carbon dioxide emission reduction goal by the end of 2025				60.00%
Company goal for percentage of carbon dioxide emissions reduction below 2005 levels by the end of 2030				80.00%
Climate Change | Electric | Minimum
Air Quality
Percent capacity factor for turbines that over this percent will require more stringent NOx limits							20.00%
Climate Change | Electric | Maximum
Air Quality
RICE unit megawatts | MW						25
Percent capacity factor for turbines that below this percentage will have less restrictive standards							20.00%
Steam Electric Effluent Guidelines | Electric
Water Quality
Number of new ELG rule requirements that affect our electric utilities | performance_obligations	3
Compliance costs through 2023 associated with the ELG rule that were required to achieve discharge limits.								105.0
Number of existing coal categories that were kept as part of the 2024 supplemental ELG rule requirements | performance_obligations	1
Number of new coal categories that were created as part of the 2024 supplemental ELG rule requirements | performance_obligations	1
Manufactured Gas Plant Remediation | Natural gas
Manufactured Gas Plant Remediation
Estimated future cash expenditures for environmental remediation						$ 445.8		463.7
Manufactured Gas Plant Remediation | Natural gas | Environmental remediation costs
Manufactured Gas Plant Remediation
Regulatory asset						$ 570.1		$ 596.8
Renewables, Efficiency, and Conservation | Electric | Wisconsin
Renewables, Efficiency, and Conservation
Annual state renewable portfolio requirement, as a percent						10.00%
Percent of annual operating revenues used to fund renewable program						1.20%
Renewables, Efficiency, and Conservation | Electric | Wisconsin | WE
Renewables, Efficiency, and Conservation
Required renewable energy percent achieved						8.27%
Renewables, Efficiency, and Conservation | Electric | Wisconsin | WPS
Renewables, Efficiency, and Conservation
Required renewable energy percent achieved						9.74%
Renewables, Efficiency, and Conservation | Electric | Michigan
Renewables, Efficiency, and Conservation
Annual state renewable portfolio requirement for 2019 and 2020, as a percent						12.50%
Annual energy optimization target, as a percent						1.00%
Percentage renewable portfolio requirement 2021 and beyond						15.00%
Required renewable energy plan filing time period | Years									2
Percentage proposed renewable energy target through 2029									15.00%
Percentage proposed renewable energy target from 2030 through 2034									50.00%
Percentage proposed renewable energy target for 2035 and thereafter									60.00%
Percentage proposed clean energy standards for 2035 through 2039									80.00%
Percentage proposed clean energy standards after 2040									100.00%
Required energy waste reduction plan filing time period until 2025 | Years									2
Required energy waste reduction plan filing time period after 2025 | Years									3