Loans - Trouble Debt Restructurings (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans Modified		$ 505
Loans modified	$ 787
Average rate reduction	0.25%
Interest rate reduction:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	$ 188
Term extension:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	240
Principal balance reduction:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	7
Interest rate reduction and term extension:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	202
Principal Balance reduction and term extension:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	17
Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	133
Credit Card
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans Modified		$ 96
Loans modified	$ 188
Average rate reduction	0.14%
Credit Card | Interest rate reduction:
Financing Receivable, Troubled Debt Restructuring [Line Items]
% of TDR Activity		100.00%
Average Rate Reduction		19.40%
Loans modified	$ 188
Average rate reduction	20.37%
Credit Card | Term extension:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	$ 0
Credit Card | Principal balance reduction:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	0
Credit Card | Interest rate reduction and term extension:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	0
Credit Card | Principal Balance reduction and term extension:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	0
Credit Card | Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	0
Credit Card | Domestic Card
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	$ 150
Average rate reduction	0.11%
Credit Card | Domestic Card | Interest rate reduction:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	$ 150
Average rate reduction	19.02%
Credit Card | Domestic Card | Term extension:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	$ 0
Credit Card | Domestic Card | Principal balance reduction:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	0
Credit Card | Domestic Card | Interest rate reduction and term extension:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	0
Credit Card | Domestic Card | Principal Balance reduction and term extension:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	0
Credit Card | Domestic Card | Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	0
Credit Card | International card businesses
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	$ 38
Average rate reduction	0.62%
Credit Card | International card businesses | Interest rate reduction:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	$ 38
Average rate reduction	25.74%
Credit Card | International card businesses | Term extension:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	$ 0
Credit Card | International card businesses | Principal balance reduction:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	0
Credit Card | International card businesses | Interest rate reduction and term extension:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	0
Credit Card | International card businesses | Principal Balance reduction and term extension:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	0
Credit Card | International card businesses | Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	0
Consumer Banking
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans Modified		$ 240
Loans modified	$ 255
Average rate reduction	0.33%
Consumer Banking | Interest rate reduction:
Financing Receivable, Troubled Debt Restructuring [Line Items]
% of TDR Activity		55.00%
Average Rate Reduction		8.80%
Loans modified	$ 0
Consumer Banking | Term extension:
Financing Receivable, Troubled Debt Restructuring [Line Items]
% of TDR Activity		97.00%
Average Term Extension (Months)		4 months
Loans modified	$ 45
Average term extension (months)	5 months
Consumer Banking | Principal balance reduction:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	$ 7
Gross balance reduction	0
Consumer Banking | Interest rate reduction and term extension:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	$ 202
Average term extension (months)	6 months
Average rate reduction	8.75%
Consumer Banking | Principal Balance reduction and term extension:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	$ 0
Consumer Banking | Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	1
Consumer Banking | Auto
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans Modified		$ 239
Loans modified	$ 252
Average rate reduction	0.33%
Consumer Banking | Auto | Interest rate reduction:
Financing Receivable, Troubled Debt Restructuring [Line Items]
% of TDR Activity		55.00%
Average Rate Reduction		8.80%
Loans modified	$ 0
Consumer Banking | Auto | Term extension:
Financing Receivable, Troubled Debt Restructuring [Line Items]
% of TDR Activity		97.00%
Average Term Extension (Months)		4 months
Loans modified	$ 42
Average term extension (months)	4 months
Consumer Banking | Auto | Principal balance reduction:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	$ 7
Gross balance reduction	0
Consumer Banking | Auto | Interest rate reduction and term extension:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	$ 202
Average term extension (months)	6 months
Average rate reduction	8.75%
Consumer Banking | Auto | Principal Balance reduction and term extension:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	$ 0
Consumer Banking | Auto | Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	1
Consumer Banking | Retail banking
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans Modified		$ 1
Loans modified	$ 3
Average rate reduction	0.18%
Consumer Banking | Retail banking | Interest rate reduction:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	$ 0
Consumer Banking | Retail banking | Term extension:
Financing Receivable, Troubled Debt Restructuring [Line Items]
% of TDR Activity		100.00%
Average Term Extension (Months)		6 months
Loans modified	$ 3
Average term extension (months)	14 months
Consumer Banking | Retail banking | Principal balance reduction:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	$ 0
Consumer Banking | Retail banking | Interest rate reduction and term extension:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	0
Consumer Banking | Retail banking | Principal Balance reduction and term extension:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	0
Consumer Banking | Retail banking | Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	0
Commercial Banking
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans Modified		$ 169
Loans modified	$ 344
Average rate reduction	0.37%
Commercial Banking | Interest rate reduction:
Financing Receivable, Troubled Debt Restructuring [Line Items]
% of TDR Activity		6.00%
Average Rate Reduction		0.59%
Loans modified	$ 0
Commercial Banking | Term extension:
Financing Receivable, Troubled Debt Restructuring [Line Items]
% of TDR Activity		68.00%
Average Term Extension (Months)		11 months
Loans modified	$ 195
Average term extension (months)	8 months
Commercial Banking | Principal balance reduction:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	$ 0
Commercial Banking | Interest rate reduction and term extension:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	0
Commercial Banking | Principal Balance reduction and term extension:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	17
Gross balance reduction	$ 3
Average term extension (months)	60 months
Commercial Banking | Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	$ 132
Commercial Banking | Commercial and multifamily real estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans Modified		$ 131
Loans modified	$ 129
Average rate reduction	0.35%
Commercial Banking | Commercial and multifamily real estate | Interest rate reduction:
Financing Receivable, Troubled Debt Restructuring [Line Items]
% of TDR Activity		7.00%
Average Rate Reduction		0.59%
Loans modified	$ 0
Commercial Banking | Commercial and multifamily real estate | Term extension:
Financing Receivable, Troubled Debt Restructuring [Line Items]
% of TDR Activity		62.00%
Average Term Extension (Months)		12 months
Loans modified	$ 129
Average term extension (months)	8 months
Commercial Banking | Commercial and multifamily real estate | Principal balance reduction:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	$ 0
Commercial Banking | Commercial and multifamily real estate | Interest rate reduction and term extension:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	0
Commercial Banking | Commercial and multifamily real estate | Principal Balance reduction and term extension:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	0
Commercial Banking | Commercial and multifamily real estate | Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	0
Commercial Banking | Commercial and industrial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans Modified		$ 38
Loans modified	$ 215
Average rate reduction	0.38%
Commercial Banking | Commercial and industrial | Interest rate reduction:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	$ 0
Commercial Banking | Commercial and industrial | Term extension:
Financing Receivable, Troubled Debt Restructuring [Line Items]
% of TDR Activity		86.00%
Average Term Extension (Months)		10 months
Loans modified	$ 66
Average term extension (months)	7 months
Commercial Banking | Commercial and industrial | Principal balance reduction:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	$ 0
Commercial Banking | Commercial and industrial | Interest rate reduction and term extension:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	0
Commercial Banking | Commercial and industrial | Principal Balance reduction and term extension:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	17
Gross balance reduction	$ 3
Average term extension (months)	60 months
Commercial Banking | Commercial and industrial | Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans modified	$ 132
Domestic credit card: | Credit Card
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans Modified		$ 62
Domestic credit card: | Credit Card | Interest rate reduction:
Financing Receivable, Troubled Debt Restructuring [Line Items]
% of TDR Activity		100.00%
Average Rate Reduction		14.67%
International card businesses: | Credit Card
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total Loans Modified		$ 34
International card businesses: | Credit Card | Interest rate reduction:
Financing Receivable, Troubled Debt Restructuring [Line Items]
% of TDR Activity		100.00%
Average Rate Reduction		28.00%