Loans Receivable (Summary of Changes In Allowance for Credit Losses) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	$ 204.8		$ 185.8		$ 195.4		$ 176.4
Provision for credit losses	4.1		6.1		13.4		17.3
Write-offs	(1.2)		(1.6)		(2.1)		(4.7)
Recoveries	0.5	[1]	0.6	[1]	1.5	[1]	1.9	[1]
Balance, end of period	208.2		190.9		208.2		190.9
Dealer Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	195.8		175.5		185.7		167.4
Provision for credit losses	4.0		6.4		14.0		16.3
Write-offs	(1.1)		(1.6)		(2.0)		(4.6)
Recoveries	0.4	[1]	0.5	[1]	1.4	[1]	1.7	[1]
Balance, end of period	199.1		180.8		199.1		180.8
Purchased Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	9.0		10.3		9.7		9.0
Provision for credit losses	0.1		(0.3)		(0.6)		1.0
Write-offs	(0.1)		0		(0.1)		(0.1)
Recoveries	0.1	[1]	0.1	[1]	0.1	[1]	0.2	[1]
Balance, end of period	$ 9.1		$ 10.1		$ 9.1		$ 10.1

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