Loans Receivable Loans Receivable (Summary of Provision for Credit Losses) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision for Credit Losses	$ 139.6	$ 161.9
Dealer Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision for Credit Losses	71.7	104.7
Purchased Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision for Credit Losses	67.9	57.2
New Consumer Loan Assignments [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision for Credit Losses	85.2	85.6
New Consumer Loan Assignments [Member] \| Dealer Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision for Credit Losses	43.4	52.1
New Consumer Loan Assignments [Member] \| Purchased Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision for Credit Losses	41.8	33.5
Forecast Changes [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision for Credit Losses	54.4	76.3
Forecast Changes [Member] \| Dealer Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision for Credit Losses	28.3	52.6
Forecast Changes [Member] \| Purchased Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision for Credit Losses	$ 26.1	$ 23.7