FINANCE RECEIVABLES - Schedule of Financing Receivable Credit Quality Indicators (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Financing Receivable, Allowance for Credit Loss [Line Items]
Total finance receivables	$ 3,739.7	$ 3,348.7
Auto Loan Receivables
Financing Receivable, Allowance for Credit Loss [Line Items]
Current year	921.5	1,707.2
Fiscal year before current fiscal year	1,442.0	1,188.6
Two years before current fiscal year	976.6	248.9
Three years before current fiscal year	194.8	27.1
Four years before current fiscal year	19.9
Total finance receivables	3,554.8	3,171.8
Other Finance Receivables
Financing Receivable, Allowance for Credit Loss [Line Items]
Total finance receivables	184.9	176.9
Less than 599 \| Auto Loan Receivables
Financing Receivable, Allowance for Credit Loss [Line Items]
Current year	32.5	62.2
Fiscal year before current fiscal year	51.8	39.0
Two years before current fiscal year	30.1	17.6
Three years before current fiscal year	13.4	2.4
Four years before current fiscal year	1.8
Total finance receivables	129.6	121.2
FICO Score, 600 to 699 \| Auto Loan Receivables
Financing Receivable, Allowance for Credit Loss [Line Items]
Current year	296.3	586.6
Fiscal year before current fiscal year	500.5	463.6
Two years before current fiscal year	377.5	152.7
Three years before current fiscal year	119.0	16.1
Four years before current fiscal year	11.7
Total finance receivables	1,305.0	1,219.0
FICO Score, 700 to 774 \| Auto Loan Receivables
Financing Receivable, Allowance for Credit Loss [Line Items]
Current year	295.9	568.1
Fiscal year before current fiscal year	487.5	422.5
Two years before current fiscal year	350.8	63.9
Three years before current fiscal year	50.5	5.9
Four years before current fiscal year	4.4
Total finance receivables	1,189.1	1,060.4
FICO Score, Greater than 775 \| Auto Loan Receivables
Financing Receivable, Allowance for Credit Loss [Line Items]
Current year	296.8	490.3
Fiscal year before current fiscal year	402.2	263.5
Two years before current fiscal year	218.2	14.7
Three years before current fiscal year	11.9	2.7
Four years before current fiscal year	2.0
Total finance receivables	$ 931.1	$ 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.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1405
-Paragraph c
-Publisher SEC

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-13

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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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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
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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
-Topic 326
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-Paragraph 79
-Publisher FASB
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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-Paragraph 6
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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-Paragraph 3B
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Amortized cost excluding accrued interest, of financing receivable originated three years prior to current fiscal year. Excludes net investment in lease.

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