Loans Receivable (Summary Of Changes In Accretable Yield) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance, beginning of period		$ 1,072.8	$ 861.7	$ 780.3
New Consumer Loan assignments	[1]	1,067.3	882.1	671.0
Accretion	[2]	(883.3)	(739.9)	(640.4)
Provision for credit losses		90.2	41.5	12.8
Forecast changes		(20.1)	23.9	33.0
Transfers	[3]	3.8	3.5	5.0
Balance, end of period		1,330.7	1,072.8	861.7
Dealer Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance, beginning of period		874.2	725.2	667.5
New Consumer Loan assignments	[1]	782.6	743.7	593.8
Accretion	[2]	(723.8)	(637.2)	(562.8)
Provision for credit losses		87.3	41.8	13.7
Forecast changes		(35.4)	3.6	19.4
Transfers	[3]	(2.3)	(2.9)	(6.4)
Balance, end of period		982.6	874.2	725.2
Purchased Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance, beginning of period		198.6	136.5	112.8
New Consumer Loan assignments	[1]	284.7	138.4	77.2
Accretion	[2]	(159.5)	(102.7)	(77.6)
Provision for credit losses		2.9	(0.3)	(0.9)
Forecast changes		15.3	20.3	13.6
Transfers	[3]	6.1	6.4	11.4
Balance, end of period		$ 348.1	$ 198.6	$ 136.5

[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] 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