DEBT (Details) € in Millions		1 Months Ended									12 Months Ended
	Dec. 20, 2019 USD ($)	Oct. 31, 2019 USD ($)	Sep. 30, 2019 EUR (€)	Sep. 30, 2019 USD ($)	Aug. 31, 2019 USD ($)	Jul. 31, 2019 EUR (€)	Jul. 31, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Feb. 28, 2019 USD ($)	Dec. 31, 2019 USD ($) item	Dec. 31, 2018 EUR (€)	Dec. 31, 2019 EUR (€)	Dec. 31, 2019 USD ($)	Dec. 19, 2019 USD ($)	May 31, 2019 USD ($)	Apr. 30, 2019 USD ($)	Dec. 31, 2018 USD ($)	Jun. 30, 2016 EUR (€)
Debt
Total long-term and other debt														$ 2,878,800,000
Less: Unamortized discount and debt issuance costs														28,900,000
Less: Current portion														6,942,400,000				$ 6,537,700,000
Long-term portion														5,209,300,000				5,256,000,000.0
Less: Current portion														3,030,800,000				2,717,600,000
Long-term portion														4,253,200,000				4,934,100,000
Mandatory payment per credit agreement																	$ 500,000,000
Loss from extinguishment of debt											$ (71,900,000)
Maturities of long-term and other debt
2020														101,400,000
2021														101,400,000
2022														1,826,000,000.0
2024														850,000,000.0
Long-Term and Other Debt														2,849,900,000
Maturities Of Deposits
2020														6,944,800,000
2021														2,193,900,000
2022														1,574,000,000.0
2023														935,000,000.0
2024														527,300,000
Total maturities														12,175,000,000.0
Unamortized discount														(23,300,000)
Total Deposits														12,151,700,000
Maturities Of Non Recourse Borrowings Of Consolidated Securitization Entities
2020														3,032,200,000
2021														2,692,100,000
2022														1,571,700,000
Total maturities														7,296,000,000.0
Unamortized discount														(12,000,000.0)
Total non-recourse borrowings of consolidated securitization entities														7,284,000,000.0
Series 2016-C asset backed term notes
Debt
Debt repaid by the company		$ 460,500,000
Retained amount of subordinated class of notes		$ 88,700,000
Series 2012-A asset backed term notes
Debt
Debt repaid by the company									$ 550,000,000.0
Retained amount of subordinated class of notes									$ 137,500,000
Series 2012-D asset backed term notes
Debt
Debt repaid by the company								$ 466,700,000
Retained amount of subordinated class of notes								77,000,000.0
Series 2017-B asset backed term notes
Debt
Debt repaid by the company					$ 444,700,000
Retained amount of subordinated class of notes					$ 44,700,000
Total deposits
Debt
Less: Unamortized discount and debt issuance costs														23,300,000				25,700,000
Deposits														12,175,000,000.0				11,819,400,000
Less: Current portion														6,942,400,000				6,537,700,000
Long-term portion														5,209,300,000				5,256,000,000.0
Certificates of deposit
Debt
Deposits														$ 8,585,200,000				$ 8,395,100,000
Certificates of deposit | Comenity Bank and Comenity Capital Bank
Debt
Weighted average interest rate (as a percent)												2.44%	2.66%	2.66%				2.44%
Money market deposits
Debt
Money market deposits														$ 3,589,800,000				$ 3,424,300,000
Debt instrument description of Variable rate basis											Federal Funds rate
Money market deposits | Comenity Bank and Comenity Capital Bank
Debt
Money market deposits														$ 3,600,000,000				$ 3,400,000
Weighted average interest rate (as a percent)												2.59%	2.05%	2.05%				2.59%
Non-recourse borrowings of consolidated securitization entities
Debt
Less: Unamortized discount and debt issuance costs														$ 12,000,000.0				$ 11,600,000
Total non-recourse borrowings of consolidated securitization entities														7,296,000,000.0				7,663,300,000
Less: Current portion														3,030,800,000				2,717,600,000
Long-term portion														4,253,200,000				4,934,100,000
Fixed rate asset-backed term note securities
Debt
Total non-recourse borrowings of consolidated securitization entities														4,891,000,000.0				4,893,300,000
Conduit asset-backed securities
Debt
Maximum borrowing capacity														4,700,000,000		$ 2,175,000,000.0	1,975,000,000.0
Total non-recourse borrowings of consolidated securitization entities														2,405,000,000.0				2,770,000,000.0
Line of credit amount outstanding														2,400,000,000
Debt instrument description of Variable rate basis											LIBOR	LIBOR
Number of facilities | item											3
Master Trust I | Series 2019-A asset backed term notes
Debt
Principal amount of debt										$ 562,500,000
Retained amount of subordinated class of notes										25,300,000
Master Trust I | Series 2019-B asset backed term notes
Debt
Principal amount of debt								399,200,000
Retained amount of subordinated class of notes								18,000,000.0
Master Trust I | Series 2019-C asset backed term notes
Debt
Principal amount of debt				$ 684,200,000
Retained amount of subordinated class of notes				30,800,000
Master Trust I | Class A notes
Debt
Principal amount of debt				$ 600,000,000.0				$ 350,000,000.0		$ 500,000,000.0
Interest Rate (as a percent)				2.21%				2.49%		3.14%
Master Trust I | Class M notes
Debt
Principal amount of debt				$ 53,400,000				$ 31,200,000		$ 37,200,000
Interest Rate (as a percent)				2.71%				3.04%		3.61%
Long-term and other debt
Debt
Total long-term and other debt														2,878,800,000				5,764,700,000
Less: Unamortized discount and debt issuance costs														28,900,000				39,300,000
Less: Current portion														101,400,000				138,900,000
Long-term and other debt														$ 2,748,500,000				5,586,500,000
Senior Notes
Debt
Extinguishment of debt							$ 1,900,000,000
Loss from extinguishment of debt							(71,900,000)
Loss from extinguishment of debt, before write-off of deferred issuance costs							(49,900,000)
Write-off of deferred issuance costs							$ 22,000,000.0
Senior Notes Due 2021
Debt
Total long-term and other debt																		500,000,000.0
Interest Rate (as a percent)							5.875%
Debt repaid by the company							$ 500,000,000.0
Senior Notes Due 2022
Debt
Total long-term and other debt																		600,000,000.0
Interest Rate (as a percent)							5.375%
Debt repaid by the company							$ 600,000,000.0
Senior Notes Due March 2022
Debt
Principal amount of debt | €													€ 400.0
Total long-term and other debt																		458,800,000
Interest Rate (as a percent)							4.50%						4.50%	4.50%
Debt repaid by the company | €						€ 400.0
Senior Notes Due 2023
Debt
Principal amount of debt | €													€ 300.0
Total long-term and other debt																		344,100,000
Interest Rate (as a percent)							5.25%						5.25%	5.25%
Debt repaid by the company | €						€ 300.0
Senior Notes Due 2024
Debt
Principal amount of debt	$ 850,000,000.0
Total long-term and other debt														$ 850,000,000.0
Interest Rate (as a percent)	4.75%												4.75%	4.75%
2017 revolving line of credit
Debt
Maximum borrowing capacity	$ 750,000,000.0						$ 1,072,400,000							$ 750,000,000.0	$ 1,072,400,000		1,072,400,000	1,572,400,000
Total long-term and other debt																		$ 740,000,000.0
Debt repaid by the company							$ 500,000,000.0
Weighted average interest rate (as a percent)												4.22%						4.22%
Threshold amount for future asset sales																	$ 50,000,000
Total availability under Credit Facility														750,000,000.0				$ 832,400,000
Debt instrument description of Variable rate basis											LIBOR
2017 Term Loans
Debt
Principal amount of debt	2,028,800,000													2,028,800,000				3,052,600,000
Total long-term and other debt														$ 2,028,800,000				$ 2,938,100,000
Debt repaid by the company	$ 833,000,000.0
Weighted average interest rate (as a percent)												4.27%	3.30%	3.30%				4.27%
Aggregate principal payments as a percentage of the initial term loan amount in each of the first and second year payable in equal quarterly installments											1.25%
Debt instrument description of Variable rate basis											LIBOR	LIBOR
BrandLoyalty credit facility
Debt
Total long-term and other debt																		$ 183,700,000
Debt instrument description of Variable rate basis												Euro Interbank Offered Rate
BrandLoyalty revolving line of credit
Debt
Debt repaid by the company | €			€ 32.5
Weighted average interest rate (as a percent)												1.22%						1.22%
BrandLoyalty revolving line of credit | Committed revolving credit facility
Debt
Maximum borrowing capacity | €												€ 37.5
BrandLoyalty revolving line of credit | Uncommitted revolving credit facility
Debt
Maximum borrowing capacity | €												€ 37.5
BrandLoyalty term loans
Debt
Debt repaid by the company | €			€ 115.0
Weighted average interest rate (as a percent)												1.65%						1.65%
BrandLoyalty term loans | A-1 Term loan facility
Debt
Principal amount of debt | €																			€ 90.0
BrandLoyalty term loans | A-2 term loan facility
Debt
Principal amount of debt | €																			€ 100.0
Minimum | Certificates of deposit
Debt
Interest Rate (as a percent)													1.33%	1.33%
Minimum | Certificates of deposit | Comenity Bank and Comenity Capital Bank
Debt
Interest Rate (as a percent)												1.25%	1.33%	1.33%				1.25%
Denomination amount of certificate of deposits											$ 1,000
Minimum | Money market deposits
Debt
Interest Rate (as a percent)												1.90%	1.84%	1.84%				1.90%
Minimum | Money market deposits | Comenity Bank and Comenity Capital Bank
Debt
Interest Rate (as a percent)												1.90%	1.84%	1.84%				1.90%
Minimum | Fixed rate asset-backed term note securities
Debt
Interest Rate (as a percent)													2.03%	2.03%
Minimum | Conduit asset-backed securities
Debt
Interest Rate (as a percent)												3.48%	2.79%	2.79%				3.48%
Maximum | Certificates of deposit
Debt
Interest Rate (as a percent)													4.00%	4.00%
Maximum | Certificates of deposit | Comenity Bank and Comenity Capital Bank
Debt
Interest Rate (as a percent)												4.00%	4.00%	4.00%				4.00%
Denomination amount of certificate of deposits											$ 100,000
Maximum | Money market deposits
Debt
Interest Rate (as a percent)												2.71%	3.50%	3.50%				2.71%
Maximum | Money market deposits | Comenity Bank and Comenity Capital Bank
Debt
Interest Rate (as a percent)												2.71%	3.50%	3.50%				2.71%
Maximum | Fixed rate asset-backed term note securities
Debt
Interest Rate (as a percent)													3.95%	3.95%
Maximum | Conduit asset-backed securities
Debt
Interest Rate (as a percent)												3.79%	2.96%	2.96%				3.79%