Loans - Schedule of Debtor Troubled Debt Restructuring, Subsequent Periods (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans		$ 120		$ 318
Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	$ 204		$ 283
Interest Rate Reduction | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	23		48
Term Extension | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	104		106
Interest Rate Reduction and Term Extension | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	77		129
Credit Card:
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans		38		105
Credit Card: | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	23		48
Credit Card: | Interest Rate Reduction | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	23		48
Credit Card: | Term Extension | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	0		0
Credit Card: | Interest Rate Reduction and Term Extension | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	0		0
Credit Card: | Domestic credit card:
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans		19		47
Credit Card: | Domestic credit card: | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	17		39
Credit Card: | Domestic credit card: | Interest Rate Reduction | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	17		39
Credit Card: | Domestic credit card: | Term Extension | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	0		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		0
Credit Card: | International card businesses:
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans		19		58
Credit Card: | International card businesses: | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	6		9
Credit Card: | International card businesses: | Interest Rate Reduction | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	6		9
Credit Card: | International card businesses: | Term Extension | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	0		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		0
Consumer Banking:
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans		82		178
Consumer Banking: | Auto
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans		82		178
Consumer Banking: | Retail banking
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans		0		0
Consumer Banking: | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	84		138
Consumer Banking: | Entity Loan Modification Program | Auto
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	84		138
Consumer Banking: | Interest Rate Reduction | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	0		0
Consumer Banking: | Interest Rate Reduction | Entity Loan Modification Program | Auto
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	0		0
Consumer Banking: | Term Extension | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	7		9
Consumer Banking: | Term Extension | Entity Loan Modification Program | Auto
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	7		9
Consumer Banking: | Interest Rate Reduction and Term Extension | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	77		129
Consumer Banking: | Interest Rate Reduction and Term Extension | Entity Loan Modification Program | Auto
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	77		129
Commercial Portfolio
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans		0		35
Commercial Portfolio | Commercial and industrial
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans		$ 0		$ 35
Commercial Portfolio | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	97		97
Commercial Portfolio | Entity Loan Modification Program | Commercial and multifamily real estate
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	46		46
Commercial Portfolio | Entity Loan Modification Program | Commercial and industrial
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	51		51
Commercial Portfolio | Interest Rate Reduction | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	0		0
Commercial Portfolio | Interest Rate Reduction | Entity Loan Modification Program | Commercial and multifamily real estate
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	0		0
Commercial Portfolio | Interest Rate Reduction | Entity Loan Modification Program | Commercial and industrial
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	0		0
Commercial Portfolio | Term Extension | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	97		97
Commercial Portfolio | Term Extension | Entity Loan Modification Program | Commercial and multifamily real estate
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	46		46
Commercial Portfolio | Term Extension | Entity Loan Modification Program | Commercial and industrial
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	51		51
Commercial Portfolio | Interest Rate Reduction and Term Extension | Entity Loan Modification Program
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	0		0
Commercial Portfolio | Interest Rate Reduction and Term Extension | Entity Loan Modification Program | Commercial and multifamily real estate
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	0		0
Commercial Portfolio | Interest Rate Reduction and Term Extension | Entity Loan Modification Program | Commercial and industrial
Financing Receivable, Modified, Subsequent Default [Line Items]
Total Loans	$ 0		$ 0