Loans Receivable (Summary of Changes In Allowance for Credit Losses) (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period		$ 217.9	$ 204.8	$ 206.9	$ 195.4
Provision for credit losses		13.2	4.1	27.8	13.4
Write-offs		(1.3)	(1.2)	(5.9)	(2.1)
Recoveries	[1],[2]	0.4	0.5	1.4	1.5
Balance, end of period		230.2	208.2	230.2	208.2
Dealer Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period		209.4	195.8	198.1	185.7
Provision for credit losses		13.4	4.0	28.2	14.0
Write-offs		(1.3)	(1.1)	(5.7)	(2.0)
Recoveries	[1],[2]	0.3	0.4	1.2	1.4
Balance, end of period		221.8	199.1	221.8	199.1
Purchased Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period		8.5	9.0	8.8	9.7
Provision for credit losses		(0.2)	0.1	(0.4)	(0.6)
Write-offs		0.0	(0.1)	(0.2)	(0.1)
Recoveries	[1],[2]	0.1	0.1	0.2	0.1
Balance, end of period		$ 8.4	$ 9.1	$ 8.4	$ 9.1

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

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