Loans Receivable (Summary of Changes In Allowance for Credit Losses) (Details) - USD ($) $ in Millions		3 Months Ended			6 Months Ended
		Jun. 30, 2015		Jun. 30, 2014	Jun. 30, 2015		Jun. 30, 2014
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period		$ 210.4		$ 200.1	$ 206.9
Provision for credit losses		8.4		4.6	14.6		$ 9.3
Write-offs		(1.4)		(0.4)	(4.6)		(0.9)
Recoveries	[1],[2]	0.5		0.5	1.0		1.0
Balance, end of period		217.9		204.8	217.9		204.8
Dealer Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period		201.6		190.8	198.1
Provision for credit losses		8.6		4.9	14.8		10.0
Write-offs		(1.3)		(0.4)	(4.4)		(0.9)
Recoveries	[1],[2]	0.5		0.5	0.9		1.0
Balance, end of period		209.4		195.8	209.4		195.8
Purchased Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period		8.8		9.3	8.8
Provision for credit losses		(0.2)		(0.3)	(0.2)		(0.7)
Write-offs		(0.1)		0.0	(0.2)		0.0
Recoveries	[1]	0.0	[2]	0.0	0.1	[2]	0.0
Balance, end of period		$ 8.5		$ 9.0	$ 8.5		$ 9.0

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

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