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Loans Receivable (Write-Offs Segmented by Year of Assignment) (Details) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract] |  |  |
Financing Receivable, Originated, More than Five Years before Current Fiscal Year, Writeoff | $ 225.4 |  |
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year, Writeoff | 277.9 |  |
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year, Writeoff | 208.9 |  |
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year, Writeoff | 226.9 |  |
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year, Writeoff | 271.3 |  |
Financing Receivable, Year One, Originated, Current Fiscal Year, Writeoff | 80.0 |  |
Allowance for Loan and Lease Losses, Write-offs | 0.0 | $ 0.0 | $ 0.0
Allowance for Credit Losses [Member] |  |  |
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract] |  |  |
Allowance for Loan and Lease Losses, Write-offs | 1,290.4 | 1,333.8 | 1,096.5
Dealer Loans [Member] |  |  |
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract] |  |  |
Financing Receivable, Originated, More than Five Years before Current Fiscal Year, Writeoff | 120.6 |  |
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year, Writeoff | 101.3 |  |
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year, Writeoff | 107.0 |  |
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year, Writeoff | 107.2 |  |
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year, Writeoff | 113.3 |  |
Financing Receivable, Year One, Originated, Current Fiscal Year, Writeoff | 17.2 |  |
Allowance for Loan and Lease Losses, Write-offs | 0.0 | 0.0 | 0.0
Dealer Loans [Member] | Allowance for Credit Losses [Member] |  |  |
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract] |  |  |
Allowance for Loan and Lease Losses, Write-offs | 566.6 | 433.4 | 286.2
Purchased Loans [Member] |  |  |
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract] |  |  |
Financing Receivable, Originated, More than Five Years before Current Fiscal Year, Writeoff | 104.8 |  |
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year, Writeoff | 176.6 |  |
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year, Writeoff | 101.9 |  |
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year, Writeoff | 119.7 |  |
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year, Writeoff | 158.0 |  |
Financing Receivable, Year One, Originated, Current Fiscal Year, Writeoff | 62.8 |  |
Allowance for Loan and Lease Losses, Write-offs | 0.0 | 0.0 | 0.0
Purchased Loans [Member] | Allowance for Credit Losses [Member] |  |  |
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract] |  |  |
Allowance for Loan and Lease Losses, Write-offs | $ 723.8 | $ 900.4 | $ 810.3

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- Definition Amount of writeoff of financing receivable originated more than five years before current fiscal year. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479294/326-20-55-79 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-6 + Details
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