Commitments and Contingencies - Environmental Matters (Details) $ in Millions	1 Months Ended							12 Months Ended
	Oct. 31, 2023 States mo	Aug. 31, 2023	May 31, 2023 performance_obligations MW	Apr. 30, 2023 MMBTU	Jan. 31, 2023 micrograms	May 31, 2021	Dec. 31, 2020 micrograms performance_obligations	Dec. 31, 2023 USD ($) performance_obligations MW generating_units	Feb. 07, 2024 micrograms	Nov. 30, 2023 Years	Jun. 30, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Manufactured Gas Plant Remediation
Regulatory asset								$ 3,274.7				$ 3,306.9
Estimated future cash expenditures for environmental remediation								463.7				499.6
Environmental remediation costs
Manufactured Gas Plant Remediation
Regulatory asset								596.8				610.7
Estimated future cash expenditures for environmental remediation								$ 463.7
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 proposed lower limit for particulate matter | MMBTU				0.01
Even lower level of particulate matter that the EPA is seeking opinions on | MMBTU				0.006
National Ambient Air Quality Standards | Electric
Air Quality
Number of states that failed to submit timely SIP revisions to address nonattainment areas classified as "moderate" for the 2015 standard | States	11
Number of months before offset sanctions take effect if the SIP is not approved | mo	18
Number of revisions necessary to meet the 2012 standard for particulate matter | performance_obligations							0
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
National Ambient Air Quality Standards | Electric | Minimum
Air Quality
Period of time for EPA review of ozone plan		3 years
Proposed primary (health-based) annual standard | micrograms					9
The EPA is taking comments on this full range of micrograms per cubic meter | micrograms					8
National Ambient Air Quality Standards | Electric | Maximum
Air Quality
Period of time for EPA review of ozone plan		5 years
Proposed primary (health-based) annual standard | micrograms					10
The EPA is taking comments on this full range of micrograms per cubic meter | micrograms					11
National Ambient Air Quality Standards | Electric | Maximum | Subsequent event
Air Quality
New primary annual PM2.5 level | micrograms									9
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 causes the rule to be highly dependent on hydrogen or carbon capture			50.00%
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%
Rules that are being proposed for natural gas-fired stationary combustion turbines | performance_obligations			1
Number of subcategories of combustion turbine unit annual capacity factors that the proposed rule will be broken up into | performance_obligations			3
Capacity of coal generation retired, in megawatts | MW								1,900
Capacity of fossil-fueled generation to be retired by the end of 2031, in megawatts | MW								1,800
Company goal for percentage 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 | Maximum
Air Quality
RICE unit megawatts | MW			25
Clean Water Act Cooling Water Intake Structure Rule | Electric
Water Quality
Number of generating units that may be retired | generating_units								4
Steam Electric Effluent Guidelines | Electric
Water Quality
Number of new ELG rule requirements that affect our electric utilities | performance_obligations								2
Capital investment that was required to achieve discharge limits								$ 105.0
Steam Electric Effluent Guidelines | Electric | WE | OCPP Units 7 and 8
Water Quality
Capital investment that was required to achieve discharge limits													$ 8.0
Steam Electric Effluent Guidelines | Electric | WE | Elm Road Generating Station
Water Quality
Capital investment that was required to achieve discharge limits													$ 89.0
Biological treatment center costs placed in service at ERGS								89.0
Steam Electric Effluent Guidelines | Electric | WPS | Weston 3
Water Quality
Capital investment that was required to achieve discharge limits											$ 8.0
Manufactured Gas Plant Remediation | Natural gas
Manufactured Gas Plant Remediation
Estimated future cash expenditures for environmental remediation								463.7				499.6
Manufactured Gas Plant Remediation | Natural gas | Environmental remediation costs
Manufactured Gas Plant Remediation
Regulatory asset								$ 596.8				$ 610.7
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, as a percent								12.50%
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 2035-2039										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