Derivative Instruments (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Derivative [Line Items]
Derivative instruments:	$ 1,256.9	$ 1,470.3
Cross-currency and interest rate derivative contracts
Derivative [Line Items]
Gain (loss) on change in credit risk valuation included in realized and unrealized gains (losses) on derivative instruments, net	36.9	(16.6)	$ (10.7)
Derivative instruments:	943.1	$ 1,469.0
Counterparty Credit Risk
Derivative [Line Items]
Derivative instruments:	$ 232.9