CAPITAL CONSTRUCTION FUND - Summary of the activities within the CCF Assigned receivables account (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
CAPITAL CONSTRUCTION FUND
CCF assigned receivables balance at beginning of period	$ 218.1	$ 9.9
Assigned account receivables		200.0
Interest earned on assigned receivables	3.2
CCF assigned receivables balance at end of period	$ 221.3	$ 209.9