Lease Accounting (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Leases [Abstract]
Operating lease costs		$ 13.6	$ 18.4	$ 30.2
Mileage credits		$ 22.4	$ 20.8	18.4
Fixed lease payments per year				$ 5.2
Fixed lease interest rate per year				10.25%
Early payment received on direct finance lease	$ 41.0
Direct finance lease receivable				$ 70.0