CREDIT LOSSES - GROSS RECEIVABLES AND RELATED ALLOWANCES (Details) - USD ($) $ in Millions	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022
Utility segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable and unbilled revenues	$ 207.8		$ 230.1
Allowance for credit losses	8.3	$ 9.6	10.9	$ 10.6	$ 13.2	$ 11.7
Accounts receivable and unbilled revenues, net	199.5		219.2
Total accounts receivable, net - past due greater than 90 days	$ 8.8		$ 8.3
Past due greater than 90 days - collection risk mitigated by regulatory mechanisms	95.50%		93.40%
Amount of net accounts receivable with regulatory protections	$ 88.8
Percent of net accounts receivable with regulatory protections	44.50%
Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable and unbilled revenues	$ 0.0		$ 0.0