Debt Debt (Schedule of Principal Debt Outstanding) (Details) - USD ($) $ in Millions		Dec. 31, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
Debt Instrument, Principal Outstanding		$ 4,616.5	$ 4,642.7
Unamortized Debt Issuance Costs		(22.4)	(26.4)
Unamortized Discount		(3.4)	0.0
Debt Instrument, Carrying Amount		4,590.7	4,616.3
Revolving Secured Line Of Credit [Member]
Debt Instrument [Line Items]
Debt Instrument, Principal Outstanding	[1]	30.9	2.6
Unamortized Debt Issuance Costs	[1]	0.0	0.0
Unamortized Discount		0.0	0.0
Debt Instrument, Carrying Amount	[1]	30.9	2.6
Secured financings [Member]
Debt Instrument [Line Items]
Debt Instrument, Principal Outstanding	[2]	3,776.7	3,830.4
Unamortized Debt Issuance Costs	[2]	(16.9)	(18.9)
Unamortized Discount		(3.4)	0.0
Debt Instrument, Carrying Amount	[2]	3,756.4	3,811.5
Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Principal Outstanding		800.0	800.0
Unamortized Debt Issuance Costs		(5.5)	(7.5)
Unamortized Discount		0.0	0.0
Debt Instrument, Carrying Amount		794.5	792.5
Mortgage [Member]
Debt Instrument [Line Items]
Debt Instrument, Principal Outstanding		8.9	9.7
Unamortized Debt Issuance Costs		0.0	0.0
Unamortized Discount		0.0	0.0
Debt Instrument, Carrying Amount		8.9	9.7
Other Assets [Member]
Debt Instrument [Line Items]
Unamortized Debt Issuance Costs	[2]	$ (3.9)	$ (3.6)

[1] Excludes deferred debt issuance costs of $3.9 million and $3.6 million as of December 31, 2022 and December 31, 2021, respectively, which are included in other assets.

[2] Warehouse facilities and Term ABS.