OPERATING REVENUES - OTHER NON-UTILITY OPERATING REVENUES (Details) - Revenues from contracts with customers - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Disaggregation of Operating Revenues
Revenues from contracts with customers	$ 2,899.6	$ 2,669.0
Other non-utility revenues
Disaggregation of Operating Revenues
Revenues from contracts with customers	46.7	26.3
Other non-utility revenues | We Power revenues
Disaggregation of Operating Revenues
Revenues from contracts with customers	5.9	5.8
Transferred over time | Other non-utility revenues | Wind generation revenues
Disaggregation of Operating Revenues
Revenues from contracts with customers	36.2	15.8
Transferred over time | Other non-utility revenues | Appliance service repairs
Disaggregation of Operating Revenues
Revenues from contracts with customers	$ 4.6	$ 4.7