Loans Receivable (Schedule Of Consumer Loans Performance) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	$ 3,345.1	$ 2,719.8	$ 2,408.2	$ 2,109.9
Allowance for credit losses	(243.6)	(206.9)	(195.4)	(176.4)
Loans receivable, net	3,101.5	2,512.9
Loan Pool Performance Meets Or Exceeds Initial Estimates [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	1,544.9	1,262.8
Allowance for credit losses	0.0	0.0
Loans receivable, net	1,544.9	1,262.8
Loan Pool Performance Less Than Initial Estimates [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	1,800.2	1,457.0
Allowance for credit losses	(243.6)	(206.9)
Loans receivable, net	1,556.6	1,250.1
Dealer Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	2,823.4	2,389.8	2,155.5	1,869.4
Allowance for credit losses	(235.1)	(198.1)	(185.7)	(167.4)
Loans receivable, net	2,588.3	2,191.7
Dealer Loans [Member] | Loan Pool Performance Meets Or Exceeds Initial Estimates [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	1,066.8	945.1
Allowance for credit losses	0.0	0.0
Loans receivable, net	1,066.8	945.1
Dealer Loans [Member] | Loan Pool Performance Less Than Initial Estimates [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	1,756.6	1,444.7
Allowance for credit losses	(235.1)	(198.1)
Loans receivable, net	1,521.5	1,246.6
Purchased Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	521.7	330.0	252.7	240.5
Allowance for credit losses	(8.5)	(8.8)	$ (9.7)	$ (9.0)
Loans receivable, net	513.2	321.2
Purchased Loans [Member] | Loan Pool Performance Meets Or Exceeds Initial Estimates [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	478.1	317.7
Allowance for credit losses	0.0	0.0
Loans receivable, net	478.1	317.7
Purchased Loans [Member] | Loan Pool Performance Less Than Initial Estimates [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	43.6	12.3
Allowance for credit losses	(8.5)	(8.8)
Loans receivable, net	$ 35.1	$ 3.5