Derivative Instruments - Location and Amounts of Interest Rate Swap Gains and Losses (Details) - Derivatives Not Designated as Hedging Instruments - Interest Rate Swaps - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Net unrealized gain (loss) on financial instruments
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate swap gains (losses)	$ 2.4	$ 17.8	$ (12.5)	$ 68.9
Financing interest expense
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate swap gains (losses)	$ 11.5	$ (3.0)	$ 23.8	$ (8.9)