FINANCE RECEIVABLES - Schedule of Finance Receivables by FICO Score (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Financing Receivable, Allowance for Credit Loss [Line Items]
Total finance receivables	$ 3,886.0	$ 3,348.7
Auto Loan Receivables
Financing Receivable, Allowance for Credit Loss [Line Items]
Current year	1,326.4	1,707.2
Fiscal year before current fiscal year	1,306.3	1,188.6
Two years before current fiscal year	879.6	248.9
Three years before current fiscal year	171.0	27.1
Four years before current fiscal year	17.0
Total finance receivables	3,700.3	3,171.8
Other Finance Receivables
Financing Receivable, Allowance for Credit Loss [Line Items]
Total finance receivables	185.7	176.9
Less than 599 \| Auto Loan Receivables
Financing Receivable, Allowance for Credit Loss [Line Items]
Current year	44.4	62.2
Fiscal year before current fiscal year	45.3	39.0
Two years before current fiscal year	26.1	17.6
Three years before current fiscal year	11.9	2.4
Four years before current fiscal year	1.6
Total finance receivables	129.3	121.2
FICO Score, 600 to 699 \| Auto Loan Receivables
Financing Receivable, Allowance for Credit Loss [Line Items]
Current year	428.7	586.6
Fiscal year before current fiscal year	452.6	463.6
Two years before current fiscal year	338.2	152.7
Three years before current fiscal year	103.9	16.1
Four years before current fiscal year	10.0
Total finance receivables	1,333.4	1,219.0
FICO Score, 700 to 774 \| Auto Loan Receivables
Financing Receivable, Allowance for Credit Loss [Line Items]
Current year	434.4	568.1
Fiscal year before current fiscal year	444.4	422.5
Two years before current fiscal year	317.9	63.9
Three years before current fiscal year	44.8	5.9
Four years before current fiscal year	3.8
Total finance receivables	1,245.3	1,060.4
FICO Score, Greater than 775 \| Auto Loan Receivables
Financing Receivable, Allowance for Credit Loss [Line Items]
Current year	418.9	490.3
Fiscal year before current fiscal year	364.0	263.5
Two years before current fiscal year	197.4	14.7
Three years before current fiscal year	10.4	2.7
Four years before current fiscal year	1.6
Total finance receivables	$ 992.3	$ 771.2

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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-Name Regulation S-K (SK)
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Amortized cost excluding accrued interest, before allowance for credit loss, of financing receivable classified as noncurrent. Excludes net investment in lease.

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Amortized cost excluding accrued interest, of financing receivable originated four years prior to current fiscal year. Excludes net investment in lease.

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Reference 1: http://www.xbrl.org/2003/role/exampleRef
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