CAPITAL CONSTRUCTION FUND - Summary of the activities within the CCF Assigned receivables account (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
CAPITAL CONSTRUCTION FUND
CCF assigned accounts receivable balance at beginning of period	$ 218.1	$ 9.9
Assigned accounts receivable		200.0
Repurchase of assigned accounts receivable	(35.8)
Interest earned on assigned accounts receivable	3.6	0.1
CCF assigned accounts receivable balance at end of period	$ 185.9	$ 210.0