Loans - TDR Disclosure - Modification to Borrowers (Details) $ in Millions	Dec. 31, 2023 USD ($)
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	$ 2,860
Commitments to lend on loans modified in TDRs	109
Current
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	2,237
30-59 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	197
60-89 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	131
Greater than 90 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	295
Total Delinquent Loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	623
Credit Card:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	699
Credit Card: | Current
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	433
Credit Card: | 30-59 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	90
Credit Card: | 60-89 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	55
Credit Card: | Greater than 90 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	121
Credit Card: | Total Delinquent Loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	266
Credit Card: | Domestic Card
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	602
Credit Card: | Domestic Card | Current
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	384
Credit Card: | Domestic Card | 30-59 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	81
Credit Card: | Domestic Card | 60-89 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	46
Credit Card: | Domestic Card | Greater than 90 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	91
Credit Card: | Domestic Card | Total Delinquent Loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	218
Credit Card: | International card businesses
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	97
Credit Card: | International card businesses | Current
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	49
Credit Card: | International card businesses | 30-59 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	9
Credit Card: | International card businesses | 60-89 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	9
Credit Card: | International card businesses | Greater than 90 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	30
Credit Card: | International card businesses | Total Delinquent Loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	48
Consumer Banking:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	772
Consumer Banking: | Current
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	558
Consumer Banking: | 30-59 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	107
Consumer Banking: | 60-89 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	76
Consumer Banking: | Greater than 90 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	31
Consumer Banking: | Total Delinquent Loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	214
Consumer Banking: | Auto
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	762
Consumer Banking: | Auto | Current
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	548
Consumer Banking: | Auto | 30-59 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	107
Consumer Banking: | Auto | 60-89 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	76
Consumer Banking: | Auto | Greater than 90 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	31
Consumer Banking: | Auto | Total Delinquent Loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	214
Consumer Banking: | Retail banking
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	10
Consumer Banking: | Retail banking | Current
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	10
Consumer Banking: | Retail banking | 30-59 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	0
Consumer Banking: | Retail banking | 60-89 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	0
Consumer Banking: | Retail banking | Greater than 90 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	0
Consumer Banking: | Retail banking | Total Delinquent Loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	0
Commercial Banking:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	1,389
Commercial Banking: | Current
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	1,246
Commercial Banking: | 30-59 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	0
Commercial Banking: | 60-89 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	0
Commercial Banking: | Greater than 90 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	143
Commercial Banking: | Total Delinquent Loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	143
Commercial Banking: | Commercial and multifamily real estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	465
Commercial Banking: | Commercial and multifamily real estate | Current
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	426
Commercial Banking: | Commercial and multifamily real estate | 30-59 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	0
Commercial Banking: | Commercial and multifamily real estate | 60-89 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	0
Commercial Banking: | Commercial and multifamily real estate | Greater than 90 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	39
Commercial Banking: | Commercial and multifamily real estate | Total Delinquent Loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	39
Commercial Banking: | Commercial and industrial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	924
Commercial Banking: | Commercial and industrial | Current
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	820
Commercial Banking: | Commercial and industrial | 30-59 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	0
Commercial Banking: | Commercial and industrial | 60-89 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	0
Commercial Banking: | Commercial and industrial | Greater than 90 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	104
Commercial Banking: | Commercial and industrial | Total Delinquent Loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	$ 104