Jointly Owned Utility Facilities (Details) $ in Millions	Dec. 31, 2021 USD ($) MW
Elm Road Generating Station Units 1 and 2 | We Power
Jointly owned utility facilities
Ownership (as a percentage)	83.34%
Share of capacity (MW) | MW	1,060.8
Property, plant, and equipment	$ 2,433.8
Accumulated depreciation	(487.7)
Construction work in progress	$ 11.1
Weston Unit 4 | WPS
Jointly owned utility facilities
Ownership (as a percentage)	70.00%
Share of capacity (MW) | MW	387.3
Property, plant, and equipment	$ 598.4
Accumulated depreciation	(224.3)
Construction work in progress	$ 3.8
Columbia Energy Center Units 1 and 2 | WPS
Jointly owned utility facilities
Ownership (as a percentage)	27.50%
Share of capacity (MW) | MW	311.1
Property, plant, and equipment	$ 425.4
Accumulated depreciation	(161.9)
Construction work in progress	$ 3.9
Forward Wind Energy Center | WPS
Jointly owned utility facilities
Ownership (as a percentage)	44.60%
Share of capacity (MW) | MW	61.5
Property, plant, and equipment	$ 122.5
Accumulated depreciation	(53.3)
Construction work in progress	$ 0.0
Two Creeks | WPS
Jointly owned utility facilities
Ownership (as a percentage)	66.70%
Share of capacity (MW) | MW	100.0
Property, plant, and equipment	$ 136.7
Accumulated depreciation	(5.3)
Construction work in progress	$ 0.0
Badger Hollow I | WPS
Jointly owned utility facilities
Ownership (as a percentage)	66.70%
Share of capacity (MW) | MW	100.0
Property, plant, and equipment	$ 134.5
Accumulated depreciation	(0.4)
Construction work in progress	$ 0.1
Badger Hollow II | WE
Jointly owned utility facilities
Ownership (as a percentage)	66.70%
Share of capacity (MW) | MW	100
Construction work in progress	$ 39.8
Red Barn Wind Park | WPS
Jointly owned utility facilities
Ownership (as a percentage)	90.00%
Share of capacity (MW) | MW	82