Operating Revenues - Other Operating Revenues (Details) - Other operating revenues - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disaggregation of Operating Revenues
Other operating revenues	$ 29.3	$ 80.3	$ 72.4
Late payment charges
Disaggregation of Operating Revenues
Other operating revenues	55.6	54.9	29.4
Alternative revenues
Disaggregation of Operating Revenues
Other operating revenues	(30.3)	21.2	38.8
Other
Disaggregation of Operating Revenues
Other operating revenues	$ 4.0	$ 4.2	$ 4.2