Summary of Significant Accounting Policies Property, Plant, and Equipment (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Software | Minimum
Property, plant, and equipment
Estimated useful life	3 years
Software | Maximum
Property, plant, and equipment
Estimated useful life	15 years
WECI Wind Generating Facility | Maximum
Property, plant, and equipment
Estimated useful life	30 years
WECI Solar Generating Facility | Maximum
Property, plant, and equipment
Estimated useful life	35 years
PWGS | Minimum
Property, plant, and equipment
Estimated useful life	10 years
PWGS | Maximum
Property, plant, and equipment
Estimated useful life	45 years
ERGS | Minimum
Property, plant, and equipment
Estimated useful life	10 years
ERGS | Maximum
Property, plant, and equipment
Estimated useful life	55 years
WE
Property, plant, and equipment
Annual utility composite depreciation rate (as a percent)	3.03%	3.06%	3.09%
WPS
Property, plant, and equipment
Annual utility composite depreciation rate (as a percent)	2.93%	2.67%	2.66%
WG
Property, plant, and equipment
Annual utility composite depreciation rate (as a percent)	2.61%	2.47%	2.44%
PGL
Property, plant, and equipment
Annual utility composite depreciation rate (as a percent)	3.13%	3.13%	3.12%
NSG
Property, plant, and equipment
Annual utility composite depreciation rate (as a percent)	2.46%	2.43%	2.52%
MERC
Property, plant, and equipment
Annual utility composite depreciation rate (as a percent)	2.60%	2.56%	2.58%
MGU
Property, plant, and equipment
Annual utility composite depreciation rate (as a percent)	2.73%	2.75%	2.70%
UMERC
Property, plant, and equipment
Annual utility composite depreciation rate (as a percent)	2.97%	3.01%	2.94%