Loans - Schedule of Debtor Troubled Debt Restructuring, Subsequent Periods (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2022
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans		$ 104	$ 198
Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	$ 95
Interest Rate Reduction | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	41
Term Extension | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	3
Interest Rate Reduction and Term Extension | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	51
Credit Card:
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans		37	67
Credit Card: | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	41
Credit Card: | Interest Rate Reduction | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	41
Credit Card: | Term Extension | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	0
Credit Card: | Interest Rate Reduction and Term Extension | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	0
Credit Card: | Domestic credit card:
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans		17	28
Credit Card: | Domestic credit card: | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	37
Credit Card: | Domestic credit card: | Interest Rate Reduction | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	37
Credit Card: | Domestic credit card: | Term Extension | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	0
Credit Card: | Domestic credit card: | Interest Rate Reduction and Term Extension | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	0
Credit Card: | International card businesses:
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans		20	39
Credit Card: | International card businesses: | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	4
Credit Card: | International card businesses: | Interest Rate Reduction | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	4
Credit Card: | International card businesses: | Term Extension | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	0
Credit Card: | International card businesses: | Interest Rate Reduction and Term Extension | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	0
Consumer Banking:
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans		63	96
Consumer Banking: | Auto
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans		$ 63	$ 96
Consumer Banking: | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	54
Consumer Banking: | Entity Loan Modification Program | Auto
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	54
Consumer Banking: | Interest Rate Reduction | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	0
Consumer Banking: | Interest Rate Reduction | Entity Loan Modification Program | Auto
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	0
Consumer Banking: | Term Extension | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	3
Consumer Banking: | Term Extension | Entity Loan Modification Program | Auto
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	3
Consumer Banking: | Interest Rate Reduction and Term Extension | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	51
Consumer Banking: | Interest Rate Reduction and Term Extension | Entity Loan Modification Program | Auto
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	$ 51