Loans Receivable (Summary of Provision for Credit Losses) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision for credit losses	$ 481.4	$ 8.4	$ 556.9
Dealer Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision for credit losses	240.4	(28.2)	239.7
Purchased Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision for credit losses	241.0	36.6	317.2
New Consumer Loan assignments
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision for credit losses	343.7	365.1	518.6
New Consumer Loan assignments | Dealer Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision for credit losses	154.8	153.1	209.7
New Consumer Loan assignments | Purchased Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision for credit losses	188.9	212.0	308.9
Forecast Changes [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision for credit losses	137.7	(356.7)	38.3
Forecast Changes [Member] | Dealer Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision for credit losses	85.6	(181.3)	30.0
Forecast Changes [Member] | Purchased Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision for credit losses	$ 52.1	$ (175.4)	$ 8.3