Loans Receivable (Summary of Information Related to New Consumer Loan Assignments) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Contractual net cash flows at the time of assignment	$ 1,009.0	[1]	$ 742.3	[1]
Expected net cash flows at the time of assignment	877.5	[2]	663.2	[2]
Fair value at the time of assignment	626.1	[3]	472.4	[3]
Dealer Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Contractual net cash flows at the time of assignment	825.3	[1]	643.3	[1]
Expected net cash flows at the time of assignment	750.1	[2]	592.0	[2]
Fair value at the time of assignment	533.5	[3]	421.3	[3]
Purchased Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Contractual net cash flows at the time of assignment	183.7	[1]	99.0	[1]
Expected net cash flows at the time of assignment	127.4	[2]	71.2	[2]
Fair value at the time of assignment	$ 92.6	[3]	$ 51.1	[3]

[1] The Dealer Loans amount represents the repayments that we were contractually owed at the time of assignment on Consumer Loans assigned under our Portfolio Program, less the related Dealer Holdback payments that we would be required to make if we collected all of the contractual repayments. The Purchased Loans amount represents the repayments that we were contractually owed at the time of assignment on Consumer Loans assigned under our Purchase Program.

[2] The Dealer Loans amount represents the repayments that we expected to collect at the time of assignment on Consumer Loans assigned under our Portfolio Program, less the related Dealer Holdback payments that we expected to make. The Purchased Loans amount represents the repayments that we expected to collect at the time of assignment on Consumer Loans assigned under our Purchase Program.

[3] The Dealer Loans amount represents advances paid to Dealers on Consumer Loans assigned under our Portfolio Program. The Purchased Loans amount represents one-time payments made to Dealers to purchase Consumer Loans assigned under our Purchase Program.