Loans Receivable (Summary Of Changes In Accretable Yield) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014		Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance, beginning of period		$ 861.7	$ 780.3		$ 718.1
New Consumer Loan assignments	[1]	882.1	671.0		615.2
Accretion	[2]	(739.9)	(640.4)	[3]	(600.4)	[3]
Provision for credit losses		41.5	12.8	[3]	21.9	[3]
Forecast changes		23.9	33.0	[3]	20.6	[3]
Transfers	[4]	3.5	5.0		4.9
Balance, end of period		1,072.8	861.7		780.3
Dealer Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance, beginning of period		725.2	667.5		602.9
New Consumer Loan assignments	[1]	743.7	593.8		564.9
Accretion	[2]	(637.2)	(562.8)	[3]	(527.7)	[3]
Provision for credit losses		41.8	13.7	[3]	21.3	[3]
Forecast changes		3.6	19.4	[3]	13.6	[3]
Transfers	[4]	(2.9)	(6.4)		(7.5)
Balance, end of period		874.2	725.2		667.5
Purchased Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance, beginning of period		136.5	112.8		115.2
New Consumer Loan assignments	[1]	138.4	77.2		50.3
Accretion	[2]	(102.7)	(77.6)	[3]	(72.7)	[3]
Provision for credit losses		(0.3)	(0.9)	[3]	0.6	[3]
Forecast changes		20.3	13.6	[3]	7.0	[3]
Transfers	[4]	6.4	11.4		12.4
Balance, end of period		$ 198.6	$ 136.5		$ 112.8

[1] The Dealer Loans amount represents the net cash flows expected at the time of assignment on Consumer Loans assigned under our Portfolio Program, less the related advances paid to Dealers. The Purchased Loans amount represents the net cash flows expected at the time of assignment on Consumer Loans assigned under our Purchase Program, less the related one-time payments made to Dealers.

[2] Represents finance charges excluding the amortization of deferred direct origination costs for Dealer Loans.

[3] We have changed the presentation from prior periods to: (i) exclude the amortization of deferred direct origination costs for Dealer Loans from accretion (finance charge income under our previous presentation) and forecast changes and (ii) present provision for credit losses and forecast changes as separate activities. Under our previous presentation, we presented: (i) finance charges as reported in our consolidated statements of income and (ii) provision for credit losses and forecast changes as a combined activity.

[4] Under our Portfolio Program, certain events may result in Dealers forfeiting their rights to Dealer Holdback. We transfer the Dealer’s outstanding Dealer Loan balance and related expected future net cash flows to Purchased Loans in the period this forfeiture occurs