Loans Receivable (Schedule Of Loans Receivable) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Jun. 30, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	$ 2,354.3	$ 2,278.5	$ 2,109.9	$ 2,047.5	$ 1,977.8	$ 1,752.9
Allowance for credit losses	(190.9)	(185.8)	(176.4)	(170.8)	(161.9)	(154.3)
Loans receivable, net	2,163.4		1,933.5
Dealer Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	2,110.0	2,041.4	1,869.4	1,807.7	1,736.6	1,506.5
Allowance for credit losses	(180.8)	(175.5)	(167.4)	(161.3)	(152.0)	(141.7)
Loans receivable, net	1,929.2		1,702.0
Purchased Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	244.3	237.1	240.5	239.8	241.2	246.4
Allowance for credit losses	(10.1)	(10.3)	(9.0)	(9.5)	(9.9)	(12.6)
Loans receivable, net	$ 234.2		$ 231.5