SIGNIFICANT ACCOUNTING POLICIES - CASH AND ACCOUNTS RECEIVABLE (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
CAPITAL CONSTRUCTION FUND
Restricted Cash	$ 2.3	$ 3.9
Allowance for doubtful accounts
Balance at Beginning of year	13.0	10.1	$ 6.3
Expense	(2.1)	3.2	4.2
Write-offs and Other	(1.0)	(0.3)	(0.4)
Balance at End of Year	$ 9.9	$ 13.0	$ 10.1