Derivative Instruments (Narrative) (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Derivative [Line Items]
Derivative assets	$ 1,589.5	$ 1,470.3
Counterparty Credit Risk
Derivative [Line Items]
Derivative assets	726.4
Interest Rate Caps
Derivative [Line Items]
Notional amount	1,200.0
Interest Rate Collars
Derivative [Line Items]
Notional amount	5,800.0
Foreign currency forward and option contracts
Derivative [Line Items]
Derivative assets	3.4	$ 1.0
Notional amount	$ 491.2