Loans - Credit Card Portfolio, Loan Modifications (Details) - Credit card $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2022 USD ($) loan_payment	Jun. 30, 2021 USD ($)
Financing Receivable, Impaired [Line Items]
Fixed payment plan period			60 months
New enrollments, percent of total retained credit card loans (less than)			1.00%
Balance of new TDRs	$ 81	$ 90	$ 163	$ 233
Weighted-average interest rate of loans – before TDR	18.94%	17.92%	18.47%	17.81%
Weighted-average interest rate of loans – after TDR	4.62%	5.15%	4.75%	5.20%
Balance of loans that redefaulted within one year of modification	$ 8	$ 13	$ 17	$ 32
Number of years before payment default under a modified loan			1 year
Modified loans, payment default, number of payments past due | loan_payment			2