Loans Receivable (Summary of Changes In Allowance for Credit Losses) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	$ 206.9		$ 195.4
Provision for credit losses	6.2		4.7
Write-offs	(3.2)		(0.5)
Recoveries	0.5	[1]	0.5	[1]
Balance, end of period	210.4		200.1
Dealer Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	198.1		185.7
Provision for credit losses	6.2		5.1
Write-offs	(3.1)		(0.5)
Recoveries	0.4	[1]	0.5	[1]
Balance, end of period	201.6		190.8
Purchased Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	8.8		9.7
Provision for credit losses	0		(0.4)
Write-offs	(0.1)		0
Recoveries	0.1	[1]
Balance, end of period	$ 8.8		$ 9.3

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