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Auto Loan Receivables (Ending Managed Receivables By Major Credit Grade) (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended | 12 Months Ended
--- | --- | --- | ---
Aug. 31, 2024 | Aug. 31, 2023 | Aug. 31, 2024 | Aug. 31, 2023 | Feb. 29, 2024
Financing Receivable, By Major Credit Grade [Line Items] |  |  |  |  |
Financing Receivable, Originated in Current Fiscal Year | $ 4,046.9 |  | $ 4,046.9 |  | $ 6,936.6
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year | 5,735.9 |  | 5,735.9 |  | 5,074.3
Financing Receivable, Originated Two Years before Latest Fiscal Year | 4,118.3 |  | 4,118.3 |  | 3,333.9
Financing Receivable, Originated Three Years before Latest Fiscal Year | 2,577.9 |  | 2,577.9 |  | 1,308.8
Financing Receivable, Originated Four Years before Latest Fiscal Year | 917.4 |  | 917.4 |  | 600.8
Financing Receivable, Originated Five or More Years before Latest Fiscal Year | 373.0 |  | 373.0 |  | 137.4
Financing Receivable, before Allowance for Credit Loss | $ 17,769.4 |  | $ 17,769.4 |  | $ 17,391.8
Total ending managed receivables as percentage by major credit grade | 100.00% |  | 100.00% |  | 100.00%
Financing Receivable, Allowance for Credit Loss, Writeoff | $ 163.8 | $ 143.2 | $ 296.9 | $ 253.0 | $ 561.5
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year, Writeoff |  |  | 106.5 |  | 129.8
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year, Writeoff |  |  | 97.7 |  | 248.6
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year, Writeoff |  |  | 59.6 |  | 41.0
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year, Writeoff |  |  | 16.9 |  | 19.7
Financing Receivable, Originated, More than Five Years before Current Fiscal Year, Writeoff |  |  | 12.3 |  | 11.4
Financing Receivable, Year One, Originated, Current Fiscal Year, Writeoff |  |  | 3.9 |  | 111.0
Core managed receivables |  |  |  |  |
Financing Receivable, By Major Credit Grade [Line Items] |  |  |  |  |
Financing Receivable, Originated in Current Fiscal Year | 3,879.1 |  | 3,879.1 |  | 6,637.6
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year | 5,521.9 |  | 5,521.9 |  | 4,898.0
Financing Receivable, Originated Two Years before Latest Fiscal Year | 3,974.1 |  | 3,974.1 |  | 3,261.3
Financing Receivable, Originated Three Years before Latest Fiscal Year | 2,519.6 |  | 2,519.6 |  | 1,299.5
Financing Receivable, Originated Four Years before Latest Fiscal Year | 910.3 |  | 910.3 |  | 588.7
Financing Receivable, Originated Five or More Years before Latest Fiscal Year | 361.8 |  | 361.8 |  | 128.2
Financing Receivable, before Allowance for Credit Loss | $ 17,166.8 |  | $ 17,166.8 |  | $ 16,813.3
Total ending managed receivables as percentage by major credit grade | 96.60% |  | 96.60% |  | 96.70%
Financing Receivable, Allowance for Credit Loss, Writeoff | $ 131.1 | 118.7 | $ 244.1 | 211.8 |
Other managed receivables |  |  |  |  |
Financing Receivable, By Major Credit Grade [Line Items] |  |  |  |  |
Financing Receivable, Allowance for Credit Loss, Writeoff | 32.7 | $ 24.5 | 52.8 | $ 41.2 |
Credit Grade A | Core managed receivables |  |  |  |  |
Financing Receivable, By Major Credit Grade [Line Items] |  |  |  |  |
Financing Receivable, Originated in Current Fiscal Year | 2,432.5 |  | 2,432.5 |  | $ 3,922.7
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year | 3,204.6 |  | 3,204.6 |  | 2,660.6
Financing Receivable, Originated Two Years before Latest Fiscal Year | 2,137.6 |  | 2,137.6 |  | 1,635.1
Financing Receivable, Originated Three Years before Latest Fiscal Year | 1,237.3 |  | 1,237.3 |  | 614.0
Financing Receivable, Originated Four Years before Latest Fiscal Year | 410.1 |  | 410.1 |  | 268.7
Financing Receivable, Originated Five or More Years before Latest Fiscal Year | 139.3 |  | 139.3 |  | 40.0
Financing Receivable, before Allowance for Credit Loss | $ 9,561.4 |  | $ 9,561.4 |  | $ 9,141.1
Total ending managed receivables as percentage by major credit grade | 53.80% |  | 53.80% |  | 52.60%
Credit Grade B | Core managed receivables |  |  |  |  |
Financing Receivable, By Major Credit Grade [Line Items] |  |  |  |  |
Financing Receivable, Originated in Current Fiscal Year | $ 1,194.6 |  | $ 1,194.6 |  | $ 2,370.8
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year | 1,987.3 |  | 1,987.3 |  | 1,738.8
Financing Receivable, Originated Two Years before Latest Fiscal Year | 1,432.4 |  | 1,432.4 |  | 1,225.9
Financing Receivable, Originated Three Years before Latest Fiscal Year | 968.0 |  | 968.0 |  | 493.3
Financing Receivable, Originated Four Years before Latest Fiscal Year | 358.6 |  | 358.6 |  | 233.4
Financing Receivable, Originated Five or More Years before Latest Fiscal Year | 155.7 |  | 155.7 |  | 61.3
Financing Receivable, before Allowance for Credit Loss | $ 6,096.6 |  | $ 6,096.6 |  | $ 6,123.5
Total ending managed receivables as percentage by major credit grade | 34.30% |  | 34.30% |  | 35.20%
Credit Grade C And Other | Core managed receivables |  |  |  |  |
Financing Receivable, By Major Credit Grade [Line Items] |  |  |  |  |
Financing Receivable, Originated in Current Fiscal Year | $ 252.0 |  | $ 252.0 |  | $ 344.1
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year | 330.0 |  | 330.0 |  | 498.6
Financing Receivable, Originated Two Years before Latest Fiscal Year | 404.1 |  | 404.1 |  | 400.3
Financing Receivable, Originated Three Years before Latest Fiscal Year | 314.3 |  | 314.3 |  | 192.2
Financing Receivable, Originated Four Years before Latest Fiscal Year | 141.6 |  | 141.6 |  | 86.6
Financing Receivable, Originated Five or More Years before Latest Fiscal Year | 66.8 |  | 66.8 |  | 26.9
Financing Receivable, before Allowance for Credit Loss | $ 1,508.8 |  | $ 1,508.8 |  | $ 1,548.7
Total ending managed receivables as percentage by major credit grade | 8.50% |  | 8.50% |  | 8.90%
Credit Grade C And Other | Other managed receivables |  |  |  |  |
Financing Receivable, By Major Credit Grade [Line Items] |  |  |  |  |
Financing Receivable, Originated in Current Fiscal Year | $ 167.8 |  | $ 167.8 |  | $ 299.0
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year | 214.0 |  | 214.0 |  | 176.3
Financing Receivable, Originated Two Years before Latest Fiscal Year | 144.2 |  | 144.2 |  | 72.6
Financing Receivable, Originated Three Years before Latest Fiscal Year | 58.3 |  | 58.3 |  | 9.3
Financing Receivable, Originated Four Years before Latest Fiscal Year | 7.1 |  | 7.1 |  | 12.1
Financing Receivable, Originated Five or More Years before Latest Fiscal Year | 11.2 |  | 11.2 |  | 9.2
Financing Receivable, before Allowance for Credit Loss | $ 602.6 |  | $ 602.6 |  | $ 578.5
Total ending managed receivables as percentage by major credit grade | 3.40% |  | 3.40% |  | 3.30%

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