Loans Receivable (Summary of Changes In Allowance for Credit Losses) (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period		$ 262.8	$ 210.4	$ 243.6	$ 206.9
Provision for credit losses		17.9	8.4	40.0	14.6
Write-offs		(4.2)	(1.4)	(7.4)	(4.6)
Recoveries	[1],[2]	0.4	0.5	0.7	1.0
Balance, end of period		276.9	217.9	276.9	217.9
Dealer Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period		254.0	201.6	235.1	198.1
Provision for credit losses		17.9	8.6	39.7	14.8
Write-offs		(4.1)	(1.3)	(7.3)	(4.4)
Recoveries	[1],[2]	0.4	0.5	0.7	0.9
Balance, end of period		268.2	209.4	268.2	209.4
Purchased Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period		8.8	8.8	8.5	8.8
Provision for credit losses		0.0	(0.2)	0.3	(0.2)
Write-offs		(0.1)	(0.1)	(0.1)	(0.2)
Recoveries	[1],[2]	0.0	0.0	0.0	0.1
Balance, end of period		$ 8.7	$ 8.5	$ 8.7	$ 8.5

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

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