Loans Receivable Loans Receivable (Summary of Past-Due Status) - USD ($) $ in Millions	Mar. 31, 2022		Dec. 31, 2021
Financing Receivable, Past Due [Line Items]
Loans receivable	$ 9,198.0	[1],[2]	$ 9,349.8
Current, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	5,926.0	[1],[2],[3],[4]	5,780.5
Past Due 11-90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	1,526.7	[1],[2],[3]	1,712.1
Past Due Over 90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	1,564.6	[1],[2],[3]	1,697.4
Post-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	180.7	[1],[2],[5]	159.8
Dealer Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	5,689.5	[1]	5,655.1
Dealer Loans [Member] | Current, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	3,804.8	[1],[3],[4]	3,632.8
Dealer Loans [Member] | Past Due 11-90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	922.0	[1],[3]	1,016.8
Dealer Loans [Member] | Past Due Over 90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	844.0	[1],[3]	896.6
Dealer Loans [Member] | Post-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	118.7	[1],[5]	108.9
Purchased Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	3,508.5	[2]	3,694.7
Purchased Loans [Member] | Current, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	2,121.2	[2],[3],[4]	2,147.7
Purchased Loans [Member] | Past Due 11-90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	604.7	[2],[3]	695.3
Purchased Loans [Member] | Past Due Over 90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	720.6	[2],[3]	800.8
Purchased Loans [Member] | Post-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	62.0	[2],[5]	50.9
Loans Originating In The Current Year
Financing Receivable, Past Due [Line Items]
Loans receivable	1,072.5	[1],[2]	3,231.7
Loans Originating In The Current Year | Current, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	1,026.0	[1],[2],[3],[4]	2,555.5
Loans Originating In The Current Year | Past Due 11-90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	46.5	[1],[2],[3]	554.5
Loans Originating In The Current Year | Past Due Over 90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	0.0	[1],[2],[3]	121.7
Loans Originating In The Current Year | Post-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	0.0	[1],[2],[5]	0.0
Loans Originating In The Current Year | Dealer Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	791.3	[1]	2,265.7
Loans Originating In The Current Year | Dealer Loans [Member] | Current, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	756.6	[1],[3],[4]	1,800.5
Loans Originating In The Current Year | Dealer Loans [Member] | Past Due 11-90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	34.7	[1],[3]	382.8
Loans Originating In The Current Year | Dealer Loans [Member] | Past Due Over 90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	0.0	[1],[3]	82.4
Loans Originating In The Current Year | Dealer Loans [Member] | Post-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	0.0	[1],[5]	0.0
Loans Originating In The Current Year | Purchased Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	281.2	[2]	966.0
Loans Originating In The Current Year | Purchased Loans [Member] | Current, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	269.4	[2],[3],[4]	755.0
Loans Originating In The Current Year | Purchased Loans [Member] | Past Due 11-90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	11.8	[2],[3]	171.7
Loans Originating In The Current Year | Purchased Loans [Member] | Past Due Over 90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	0.0	[2],[3]	39.3
Loans Originating In The Current Year | Purchased Loans [Member] | Post-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	0.0	[2],[5]	0.0
Loans Originating In The Prior Year
Financing Receivable, Past Due [Line Items]
Loans receivable	2,934.0	[1],[2]	2,530.5
Loans Originating In The Prior Year | Current, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	2,192.2	[1],[2],[3],[4]	1,586.4
Loans Originating In The Prior Year | Past Due 11-90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	542.9	[1],[2],[3]	538.6
Loans Originating In The Prior Year | Past Due Over 90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	198.9	[1],[2],[3]	405.5
Loans Originating In The Prior Year | Post-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	0.0	[1],[2],[5]	0.0
Loans Originating In The Prior Year | Dealer Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	2,037.7	[1]	1,617.4
Loans Originating In The Prior Year | Dealer Loans [Member] | Current, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	1,527.4	[1],[3],[4]	1,025.5
Loans Originating In The Prior Year | Dealer Loans [Member] | Past Due 11-90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	375.3	[1],[3]	337.9
Loans Originating In The Prior Year | Dealer Loans [Member] | Past Due Over 90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	135.0	[1],[3]	254.0
Loans Originating In The Prior Year | Dealer Loans [Member] | Post-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	0.0	[1],[5]	0.0
Loans Originating In The Prior Year | Purchased Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	896.3	[2]	913.1
Loans Originating In The Prior Year | Purchased Loans [Member] | Current, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	664.8	[2],[3],[4]	560.9
Loans Originating In The Prior Year | Purchased Loans [Member] | Past Due 11-90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	167.6	[2],[3]	200.7
Loans Originating In The Prior Year | Purchased Loans [Member] | Past Due Over 90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	63.9	[2],[3]	151.5
Loans Originating In The Prior Year | Purchased Loans [Member] | Post-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	0.0	[2],[5]	0.0
Loans Originating Two Years Prior
Financing Receivable, Past Due [Line Items]
Loans receivable	2,215.3	[1],[2]	2,078.0
Loans Originating Two Years Prior | Current, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	1,355.4	[1],[2],[3],[4]	1,085.4
Loans Originating Two Years Prior | Past Due 11-90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	443.7	[1],[2],[3]	410.7
Loans Originating Two Years Prior | Past Due Over 90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	416.1	[1],[2],[3]	580.8
Loans Originating Two Years Prior | Post-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	0.1	[1],[2],[5]	1.1
Loans Originating Two Years Prior | Dealer Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	1,401.0	[1]	1,001.9
Loans Originating Two Years Prior | Dealer Loans [Member] | Current, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	864.9	[1],[3],[4]	530.7
Loans Originating Two Years Prior | Dealer Loans [Member] | Past Due 11-90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	276.6	[1],[3]	194.2
Loans Originating Two Years Prior | Dealer Loans [Member] | Past Due Over 90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	259.4	[1],[3]	276.3
Loans Originating Two Years Prior | Dealer Loans [Member] | Post-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	0.1	[1],[5]	0.7
Loans Originating Two Years Prior | Purchased Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	814.3	[2]	1,076.1
Loans Originating Two Years Prior | Purchased Loans [Member] | Current, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	490.5	[2],[3],[4]	554.7
Loans Originating Two Years Prior | Purchased Loans [Member] | Past Due 11-90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	167.1	[2],[3]	216.5
Loans Originating Two Years Prior | Purchased Loans [Member] | Past Due Over 90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	156.7	[2],[3]	304.5
Loans Originating Two Years Prior | Purchased Loans [Member] | Post-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	0.0	[2],[5]	0.4
Loans Originating Three Years Prior
Financing Receivable, Past Due [Line Items]
Loans receivable	1,750.8	[1],[2]	1,024.1
Loans Originating Three Years Prior | Current, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	907.0	[1],[2],[3],[4]	452.4
Loans Originating Three Years Prior | Past Due 11-90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	325.6	[1],[2],[3]	169.9
Loans Originating Three Years Prior | Past Due Over 90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	515.9	[1],[2],[3]	395.1
Loans Originating Three Years Prior | Post-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	2.3	[1],[2],[5]	6.7
Loans Originating Three Years Prior | Dealer Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	834.9	[1]	512.8
Loans Originating Three Years Prior | Dealer Loans [Member] | Current, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	437.2	[1],[3],[4]	228.7
Loans Originating Three Years Prior | Dealer Loans [Member] | Past Due 11-90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	153.1	[1],[3]	84.0
Loans Originating Three Years Prior | Dealer Loans [Member] | Past Due Over 90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	243.2	[1],[3]	195.9
Loans Originating Three Years Prior | Dealer Loans [Member] | Post-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	1.4	[1],[5]	4.2
Loans Originating Three Years Prior | Purchased Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	915.9	[2]	511.3
Loans Originating Three Years Prior | Purchased Loans [Member] | Current, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	469.8	[2],[3],[4]	223.7
Loans Originating Three Years Prior | Purchased Loans [Member] | Past Due 11-90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	172.5	[2],[3]	85.9
Loans Originating Three Years Prior | Purchased Loans [Member] | Past Due Over 90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	272.7	[2],[3]	199.2
Loans Originating Three Years Prior | Purchased Loans [Member] | Post-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	0.9	[2],[5]	2.5
Loans Originating Four Years Prior
Financing Receivable, Past Due [Line Items]
Loans receivable	816.8	[1],[2]	318.6
Loans Originating Four Years Prior | Current, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	362.9	[1],[2],[3],[4]	93.4
Loans Originating Four Years Prior | Past Due 11-90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	134.6	[1],[2],[3]	35.0
Loans Originating Four Years Prior | Past Due Over 90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	307.9	[1],[2],[3]	155.7
Loans Originating Four Years Prior | Post-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	11.4	[1],[2],[5]	34.5
Loans Originating Four Years Prior | Dealer Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	405.1	[1]	158.7
Loans Originating Four Years Prior | Dealer Loans [Member] | Current, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	180.6	[1],[3],[4]	44.9
Loans Originating Four Years Prior | Dealer Loans [Member] | Past Due 11-90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	66.9	[1],[3]	16.8
Loans Originating Four Years Prior | Dealer Loans [Member] | Past Due Over 90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	150.4	[1],[3]	75.2
Loans Originating Four Years Prior | Dealer Loans [Member] | Post-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	7.2	[1],[5]	21.8
Loans Originating Four Years Prior | Purchased Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	411.7	[2]	159.9
Loans Originating Four Years Prior | Purchased Loans [Member] | Current, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	182.3	[2],[3],[4]	48.5
Loans Originating Four Years Prior | Purchased Loans [Member] | Past Due 11-90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	67.7	[2],[3]	18.2
Loans Originating Four Years Prior | Purchased Loans [Member] | Past Due Over 90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	157.5	[2],[3]	80.5
Loans Originating Four Years Prior | Purchased Loans [Member] | Post-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	4.2	[2],[5]	12.7
Loans Originating Five Years Prior And Before
Financing Receivable, Past Due [Line Items]
Loans receivable	408.6	[1],[2]	166.9
Loans Originating Five Years Prior And Before | Current, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	82.5	[1],[2],[3],[4]	7.4
Loans Originating Five Years Prior And Before | Past Due 11-90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	33.4	[1],[2],[3]	3.4
Loans Originating Five Years Prior And Before | Past Due Over 90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	125.8	[1],[2],[3]	38.6
Loans Originating Five Years Prior And Before | Post-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	166.9	[1],[2],[5]	117.5
Loans Originating Five Years Prior And Before | Dealer Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	219.5	[1]	98.6
Loans Originating Five Years Prior And Before | Dealer Loans [Member] | Current, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	38.1	[1],[3],[4]	2.5
Loans Originating Five Years Prior And Before | Dealer Loans [Member] | Past Due 11-90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	15.4	[1],[3]	1.1
Loans Originating Five Years Prior And Before | Dealer Loans [Member] | Past Due Over 90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	56.0	[1],[3]	12.8
Loans Originating Five Years Prior And Before | Dealer Loans [Member] | Post-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	110.0	[1],[5]	82.2
Loans Originating Five Years Prior And Before | Purchased Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	189.1	[2]	68.3
Loans Originating Five Years Prior And Before | Purchased Loans [Member] | Current, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	44.4	[2],[3],[4]	4.9
Loans Originating Five Years Prior And Before | Purchased Loans [Member] | Past Due 11-90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	18.0	[2],[3]	2.3
Loans Originating Five Years Prior And Before | Purchased Loans [Member] | Past Due Over 90 Days, Pre-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	69.8	[2],[3]	25.8
Loans Originating Five Years Prior And Before | Purchased Loans [Member] | Post-term [Member]
Financing Receivable, Past Due [Line Items]
Loans receivable	$ 56.9	[2],[5]	$ 35.3

[1] As Consumer Loans are aggregated by Dealer for purposes of recognizing revenue and measuring credit losses, the Dealer Loan amount was estimated by allocating the balance of each Dealer Loan to the underlying Consumer Loans based on the forecasted future collections of each Consumer Loan.

[2] As certain Consumer Loans are aggregated by Dealer or month of purchase for purposes of recognizing revenue and measuring credit losses, the Purchased Loan amount was estimated by allocating the balance of certain Purchased Loans to the underlying Consumer Loans based on the forecasted future collections of each Consumer Loan.

[3] Represents the Loan balance attributable to Consumer Loans outstanding within their initial loan terms.

[4] We consider a Consumer Loan to be current for purposes of forecasting expected collection rates if contractual repayments are less than 11 days past due.

[5] Represents the Loan balance attributable to Consumer Loans outstanding beyond their initial loan terms.