CREDIT CARD AND OTHER LOANS - Allowance for Loan Loss and Delinquencies (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Receivables	$ 16,529		$ 16,529			$ 16,284
Total credit card and other loans	17,769		17,769			17,399
Total credit card loans - available to settle obligations of consolidated VIEs	12,369		12,369			11,215
Unbilled finance charges	243		243			224
Allowance for credit losses	(1,992)	$ (1,635)	(1,992)	$ (1,635)	$ (1,826)	(1,832)	$ (1,843)	$ (2,008)
Credit card and loan receivables, net	$ 15,777		$ 15,777			15,567
Period an account becomes past due before a proprietary collection scoring algorithm automatically scores the risk of an account becoming further delinquent			30 days
Principal receivables balances contractually delinquent:
Re-aged accounts as percentage of total credit card and loan receivables	1.60%	2.10%	1.60%	2.30%
Modified Credit Card Receivables
Impaired credit card and loan receivables	$ 252		$ 252			281
Allowance for loan loss on impaired credit card receivables	$ 66		$ 66			$ 81
Maximum percentage of credit card receivables to total portfolio	2.00%		2.00%			2.00%
Average recorded investment in impaired credit card receivables	$ 258	$ 415	$ 265	$ 449
Interest income on modified credit card receivables	3	7	$ 7	16
Number of days a loan is contractually past due before resulting in charge-off			180 days
Number of days after notification of creditor's bankruptcy or death when an account is charged-off			60 days
Actual charge-offs for unpaid interest and fees	148	$ 114	$ 284	$ 245
Consolidated Variable Interest Entities
Total credit card loans - available to settle obligations of consolidated VIEs	12,369		12,369			$ 11,215
Credit card loans
Receivables	17,536		$ 17,536			17,217
Modified Credit Card Receivables
Maximum period of time temporary programs' concessions remain in place			12 months
Credit card loans | Maximum
Modified Credit Card Receivables
Number of days after notification of creditor's bankruptcy or death when an account is charged-off			180 days
Installment (other) loans
Receivables	233		$ 233			182
Allowance for credit losses	$ (17)		$ (17)			$ (14)
Period for which interest and fee income accrue until balance, interest and other fees are paid or charged off on installment loan receivables			120 days
Installment (other) loans | Maximum
Period for which interest and fee income accrue until balance, interest and other fees are paid or charged off on installment loan receivables			120 days