Investments in Joint Ventures - Schedule of results of operations of the joint ventures (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Operating Revenue and Expenses
Revenues	$ 294.9	$ 270.5	$ 852.2	$ 771.6
Expenses	173.3	151.5	504.2	430.6
Excess of revenues over expenses	$ 121.6	$ 119.0	$ 348.0	$ 341.0