Operating Revenues - Other Operating Revenues (Details) - Other operating revenues - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Disaggregation of Operating Revenues
Other operating revenues	$ 132.2	$ 107.7	$ 29.3
Alternative revenues
Disaggregation of Operating Revenues
Other operating revenues	79.8	47.0	(30.3)
Late payment charges
Disaggregation of Operating Revenues
Other operating revenues	48.5	56.5	55.6
Other
Disaggregation of Operating Revenues
Other operating revenues	$ 3.9	$ 4.2	$ 4.0