Loans - TDR Disclosure - Modification to Borrowers (Details) $ in Millions	Jun. 30, 2023 USD ($)
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	$ 1,534
Current
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	1,138
30-59 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	97
60-89 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	72
Greater than 90 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	227
Total Delinquent Loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	396
Credit Card:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	346
Credit Card: | Current
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	184
Credit Card: | 30-59 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	48
Credit Card: | 60-89 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	33
Credit Card: | Greater than 90 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	81
Credit Card: | Total Delinquent Loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	162
Credit Card: | Domestic Card
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	285
Credit Card: | Domestic Card | Current
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	160
Credit Card: | Domestic Card | 30-59 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	42
Credit Card: | Domestic Card | 60-89 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	27
Credit Card: | Domestic Card | Greater than 90 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	56
Credit Card: | Domestic Card | Total Delinquent Loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	125
Credit Card: | International card businesses
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	61
Credit Card: | International card businesses | Current
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	24
Credit Card: | International card businesses | 30-59 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	6
Credit Card: | International card businesses | 60-89 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	6
Credit Card: | International card businesses | Greater than 90 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	25
Credit Card: | International card businesses | Total Delinquent Loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	37
Consumer Banking:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	424
Consumer Banking: | Current
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	340
Consumer Banking: | 30-59 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	49
Consumer Banking: | 60-89 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	26
Consumer Banking: | Greater than 90 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	9
Consumer Banking: | Total Delinquent Loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	84
Consumer Banking: | Auto
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	421
Consumer Banking: | Auto | Current
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	337
Consumer Banking: | Auto | 30-59 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	49
Consumer Banking: | Auto | 60-89 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	26
Consumer Banking: | Auto | Greater than 90 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	9
Consumer Banking: | Auto | Total Delinquent Loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	84
Consumer Banking: | Retail banking
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	3
Consumer Banking: | Retail banking | Current
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	3
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 Portfolio
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	764
Commercial Portfolio | Current
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	614
Commercial Portfolio | 30-59 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	0
Commercial Portfolio | 60-89 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	13
Commercial Portfolio | Greater than 90 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	137
Commercial Portfolio | Total Delinquent Loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	150
Commercial Portfolio | Commercial and multifamily real estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	364
Commercial Portfolio | Commercial and multifamily real estate | Current
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	339
Commercial Portfolio | Commercial and multifamily real estate | 30-59 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	0
Commercial Portfolio | Commercial and multifamily real estate | 60-89 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	0
Commercial Portfolio | Commercial and multifamily real estate | Greater than 90 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	25
Commercial Portfolio | Commercial and multifamily real estate | Total Delinquent Loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	25
Commercial Portfolio | Commercial and industrial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	400
Commercial Portfolio | Commercial and industrial | Current
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	275
Commercial Portfolio | Commercial and industrial | 30-59 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	0
Commercial Portfolio | Commercial and industrial | 60-89 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	13
Commercial Portfolio | Commercial and industrial | Greater than 90 days
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	112
Commercial Portfolio | Commercial and industrial | Total Delinquent Loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans	$ 125