v3.26.3
Auto Loans Held for Investment (By Major Credit Grade) (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended 12 Months Ended
Aug. 31, 2026
Aug. 31, 2025
Aug. 31, 2026
Aug. 31, 2025
Feb. 28, 2026
Financing Receivable, By Major Credit Grade [Line Items]          
Financing Receivable, Originated in Current Fiscal Year $ 3,989.7   $ 3,989.7   $ 6,125.8
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year 4,791.5   4,791.5   4,388.2
Financing Receivable, Originated Two Years before Latest Fiscal Year 3,494.0   3,494.0   2,940.4
Financing Receivable, Originated Three Years before Latest Fiscal Year 2,200.4   2,200.4   1,824.2
Financing Receivable, Originated Four Years before Latest Fiscal Year 1,235.1   1,235.1   842.0
Financing Receivable, Originated Five or More Years before Latest Fiscal Year 488.0   488.0   151.3
Financing Receivable, before Allowance for Credit Loss $ 16,198.7   $ 16,198.7   $ 16,271.9
Total ending managed receivables as percentage by major credit grade 100.00%   100.00%   100.00%
Financing Receivable, Allowance for Credit Loss, Writeoff $ 145.6 $ 168.7 $ 279.5 $ 310.4 $ 636.1
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year, Writeoff     65.7   183.5
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year, Writeoff     68.1   153.7
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year, Writeoff     67.0   152.5
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year, Writeoff     49.4   78.3
Financing Receivable, Originated, More than Five Years before Current Fiscal Year, Writeoff     26.0   25.2
Financing Receivable, Year One, Originated, Current Fiscal Year, Writeoff     3.3   42.9
Tier 1          
Financing Receivable, By Major Credit Grade [Line Items]          
Financing Receivable, Originated in Current Fiscal Year 3,657.7   3,657.7   5,942.1
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year 4,638.9   4,638.9   4,216.2
Financing Receivable, Originated Two Years before Latest Fiscal Year 3,356.4   3,356.4   2,832.3
Financing Receivable, Originated Three Years before Latest Fiscal Year 2,117.0   2,117.0   1,762.9
Financing Receivable, Originated Four Years before Latest Fiscal Year 1,191.2   1,191.2   819.8
Financing Receivable, Originated Five or More Years before Latest Fiscal Year 471.9   471.9   148.2
Financing Receivable, before Allowance for Credit Loss $ 15,433.1   $ 15,433.1   $ 15,721.5
Total ending managed receivables as percentage by major credit grade 95.30%   95.30%   96.60%
Financing Receivable, Allowance for Credit Loss, Writeoff $ 122.5 141.3 $ 237.6 261.5  
Tier 2 & Tier 3          
Financing Receivable, By Major Credit Grade [Line Items]          
Financing Receivable, Allowance for Credit Loss, Writeoff 23.1 $ 27.4 41.9 $ 48.9  
Credit Grade A | Tier 1          
Financing Receivable, By Major Credit Grade [Line Items]          
Financing Receivable, Originated in Current Fiscal Year 2,420.5   2,420.5   $ 3,871.5
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year 3,152.6   3,152.6   2,738.1
Financing Receivable, Originated Two Years before Latest Fiscal Year 2,162.9   2,162.9   1,578.8
Financing Receivable, Originated Three Years before Latest Fiscal Year 1,151.7   1,151.7   887.9
Financing Receivable, Originated Four Years before Latest Fiscal Year 573.2   573.2   352.4
Financing Receivable, Originated Five or More Years before Latest Fiscal Year 179.5   179.5   45.2
Financing Receivable, before Allowance for Credit Loss $ 9,640.4   $ 9,640.4   $ 9,473.9
Total ending managed receivables as percentage by major credit grade 59.50%   59.50%   58.20%
Credit Grade B | Tier 1          
Financing Receivable, By Major Credit Grade [Line Items]          
Financing Receivable, Originated in Current Fiscal Year $ 1,054.2   $ 1,054.2   $ 1,643.7
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year 1,182.0   1,182.0   1,233.9
Financing Receivable, Originated Two Years before Latest Fiscal Year 995.4   995.4   1,075.2
Financing Receivable, Originated Three Years before Latest Fiscal Year 828.0   828.0   687.0
Financing Receivable, Originated Four Years before Latest Fiscal Year 484.2   484.2   352.0
Financing Receivable, Originated Five or More Years before Latest Fiscal Year 213.4   213.4   65.0
Financing Receivable, before Allowance for Credit Loss $ 4,757.2   $ 4,757.2   $ 5,056.8
Total ending managed receivables as percentage by major credit grade 29.40%   29.40%   31.10%
Credit Grade C And Other | Tier 1          
Financing Receivable, By Major Credit Grade [Line Items]          
Financing Receivable, Originated in Current Fiscal Year $ 183.0   $ 183.0   $ 426.9
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year 304.3   304.3   244.2
Financing Receivable, Originated Two Years before Latest Fiscal Year 198.1   198.1   178.3
Financing Receivable, Originated Three Years before Latest Fiscal Year 137.3   137.3   188.0
Financing Receivable, Originated Four Years before Latest Fiscal Year 133.8   133.8   115.4
Financing Receivable, Originated Five or More Years before Latest Fiscal Year 79.0   79.0   38.0
Financing Receivable, before Allowance for Credit Loss $ 1,035.5   $ 1,035.5   $ 1,190.8
Total ending managed receivables as percentage by major credit grade 6.40%   6.40%   7.30%
Credit Grade C And Other | Tier 2 & Tier 3          
Financing Receivable, By Major Credit Grade [Line Items]          
Financing Receivable, Originated in Current Fiscal Year $ 332.0   $ 332.0   $ 183.7
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year 152.6   152.6   172.0
Financing Receivable, Originated Two Years before Latest Fiscal Year 137.6   137.6   108.1
Financing Receivable, Originated Three Years before Latest Fiscal Year 83.4   83.4   61.3
Financing Receivable, Originated Four Years before Latest Fiscal Year 43.9   43.9   22.2
Financing Receivable, Originated Five or More Years before Latest Fiscal Year 16.1   16.1   3.1
Financing Receivable, before Allowance for Credit Loss $ 765.6   $ 765.6   $ 550.4
Total ending managed receivables as percentage by major credit grade 4.70%   4.70%   3.40%