OPERATING REVENUES - OTHER NON-UTILITY OPERATING REVENUES (Details) - Revenues from contracts with customers - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disaggregation of Operating Revenues
Revenues from contracts with customers	$ 2,604.5	$ 2,858.2
Other non-utility revenues
Disaggregation of Operating Revenues
Revenues from contracts with customers	55.5	47.1
Other non-utility revenues | We Power revenues
Disaggregation of Operating Revenues
Revenues from contracts with customers	6.0	5.9
Transferred over time | Other non-utility revenues | Wind generation revenues
Disaggregation of Operating Revenues
Revenues from contracts with customers	44.5	36.0
Transferred over time | Other non-utility revenues | Appliance service revenues
Disaggregation of Operating Revenues
Revenues from contracts with customers	$ 5.0	$ 5.2