Loans Receivable (Summary Of Changes In Loans Receivable) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance, beginning of period	$ 2,210.3		$ 1,897.2		$ 2,109.9		$ 1,752.9
New Consumer Loan assignments	362.5		326.9		769.0		736.1
Principal collected on Loans receivable	(332.4)		(286.7)		(677.9)		(597.6)
Accelerated Dealer Holdback payments	10.9		11.3		20.4		24.2
Dealer Holdback payments	28.5		29.4		58.5		62.6
Write-offs	(2.0)		(0.8)		(3.1)		(1.5)
Recoveries	0.7	[1]	0.5	[1]	1.3	[1]	1.1	[1]
Net change in other loans					0.4
Balance, end of period	2,278.5		1,977.8		2,278.5		1,977.8
Dealer Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance, beginning of period	1,973.1		1,652.1		1,869.4		1,506.5
New Consumer Loan assignments	334.1		301.0		712.7		675.4
Principal collected on Loans receivable	(300.0)		(252.3)		(609.3)		(522.0)
Accelerated Dealer Holdback payments	10.9		11.3		20.4		24.2
Dealer Holdback payments	28.5		29.4		58.5		62.6
Transfers	(3.9)		(5.0)		(8.9)		(10.2)
Write-offs	(1.9)		(0.4)		(3.0)		(1.0)
Recoveries	0.6	[1]	0.5	[1]	1.2	[1]	1.1	[1]
Net change in other loans					0.4
Balance, end of period	2,041.4		1,736.6		2,041.4		1,736.6
Purchased Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance, beginning of period	237.2		245.1		240.5		246.4
New Consumer Loan assignments	28.4		25.9		56.3		60.7
Principal collected on Loans receivable	(32.4)		(34.4)		(68.6)		(75.6)
Transfers	3.9		5.0		8.9		10.2
Write-offs	(0.1)		(0.4)		(0.1)		(0.5)
Recoveries	0.1	[1]			0.1	[1]
Balance, end of period	$ 237.1		$ 241.2		$ 237.1		$ 241.2

[1] Represents collections received on previously written off Loans.