Loans - Financing Receivable, Modified - Modification to Borrowers (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2023
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 875	$ 1,534
Financing Receivable, Modified in Period, to Total Financing Receivables, Percentage	0.28%	0.49%
Interest Rate Reduction
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 194	$ 346
Term Extension
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	361	563
Principal Forgiveness [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	71	76
Extended Maturity and Principal Forgiveness [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount		17
Interest Rate Reduction and Term Extension
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	173	330
Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	76	202
Credit Card:
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 194	$ 346
Financing Receivable, Modified in Period, to Total Financing Receivables, Percentage	0.14%	0.24%
Credit Card: | Interest Rate Reduction
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 194	$ 346
Credit Card: | Term Extension
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Credit Card: | Principal Forgiveness [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Credit Card: | Extended Maturity and Principal Forgiveness [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount		0
Credit Card: | Interest Rate Reduction and Term Extension
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Credit Card: | Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Credit Card: | Domestic Card
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 154	$ 285
Financing Receivable, Modified in Period, to Total Financing Receivables, Percentage	0.11%	0.21%
Credit Card: | Domestic Card | Interest Rate Reduction
Financing Receivable, Past Due [Line Items]
Weighted-average interest rate reduction	19.06%	19.04%
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 154	$ 285
Credit Card: | Domestic Card | Term Extension
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Credit Card: | Domestic Card | Principal Forgiveness [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Credit Card: | Domestic Card | Extended Maturity and Principal Forgiveness [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount		0
Credit Card: | Domestic Card | Interest Rate Reduction and Term Extension
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Credit Card: | Domestic Card | Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Credit Card: | International card businesses
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 40	$ 61
Financing Receivable, Modified in Period, to Total Financing Receivables, Percentage	0.61%	0.94%
Credit Card: | International card businesses | Interest Rate Reduction
Financing Receivable, Past Due [Line Items]
Weighted-average interest rate reduction	27.99%	26.90%
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 40	$ 61
Credit Card: | International card businesses | Term Extension
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Credit Card: | International card businesses | Principal Forgiveness [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Credit Card: | International card businesses | Extended Maturity and Principal Forgiveness [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount		0
Credit Card: | International card businesses | Interest Rate Reduction and Term Extension
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Credit Card: | International card businesses | Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Consumer Banking:
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 223	$ 424
Financing Receivable, Modified in Period, to Total Financing Receivables, Percentage	0.29%	0.55%
Consumer Banking: | Interest Rate Reduction
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0	$ 0
Consumer Banking: | Term Extension
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	42	80
Consumer Banking: | Principal Forgiveness [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	7	12
Consumer Banking: | Extended Maturity and Principal Forgiveness [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount		0
Consumer Banking: | Interest Rate Reduction and Term Extension
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	173	330
Consumer Banking: | Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	1	2
Consumer Banking: | Auto
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 222	$ 421
Financing Receivable, Modified in Period, to Total Financing Receivables, Percentage	0.29%	0.55%
Consumer Banking: | Auto | Interest Rate Reduction
Financing Receivable, Past Due [Line Items]
Weighted-average interest rate reduction	8.82%	8.78%
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0	$ 0
Consumer Banking: | Auto | Term Extension
Financing Receivable, Past Due [Line Items]
Payment delay duration (in months)	6 months	6 months
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 41	$ 77
Consumer Banking: | Auto | Principal Forgiveness [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	7	12
Consumer Banking: | Auto | Extended Maturity and Principal Forgiveness [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount		0
Consumer Banking: | Auto | Interest Rate Reduction and Term Extension
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	173	330
Consumer Banking: | Auto | Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	1	2
Consumer Banking: | Retail banking
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 1	$ 3
Financing Receivable, Modified in Period, to Total Financing Receivables, Percentage	0.08%	0.21%
Consumer Banking: | Retail banking | Interest Rate Reduction
Financing Receivable, Past Due [Line Items]
Weighted-average interest rate reduction	2.00%	2.00%
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0	$ 0
Consumer Banking: | Retail banking | Term Extension
Financing Receivable, Past Due [Line Items]
Payment delay duration (in months)	20 months	15 months
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 1	$ 3
Consumer Banking: | Retail banking | Principal Forgiveness [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Consumer Banking: | Retail banking | Extended Maturity and Principal Forgiveness [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount		0
Consumer Banking: | Retail banking | Interest Rate Reduction and Term Extension
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Consumer Banking: | Retail banking | Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Commercial Portfolio
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 458	$ 764
Financing Receivable, Modified in Period, to Total Financing Receivables, Percentage	0.50%	0.83%
Commercial Portfolio | Interest Rate Reduction
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0	$ 0
Commercial Portfolio | Term Extension
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	319	483
Commercial Portfolio | Principal Forgiveness [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	64	64
Commercial Portfolio | Extended Maturity and Principal Forgiveness [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount		17
Commercial Portfolio | Interest Rate Reduction and Term Extension
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Commercial Portfolio | Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	75	200
Commercial Portfolio | Commercial and multifamily real estate
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 265	$ 364
Financing Receivable, Modified in Period, to Total Financing Receivables, Percentage	0.74%	1.01%
Commercial Portfolio | Commercial and multifamily real estate | Interest Rate Reduction
Financing Receivable, Past Due [Line Items]
Weighted-average interest rate reduction	0.00%	0.00%
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0	$ 0
Commercial Portfolio | Commercial and multifamily real estate | Term Extension
Financing Receivable, Past Due [Line Items]
Payment delay duration (in months)	16 months	16 months
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 147	$ 246
Commercial Portfolio | Commercial and multifamily real estate | Principal Forgiveness [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	64	64
Commercial Portfolio | Commercial and multifamily real estate | Extended Maturity and Principal Forgiveness [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount		0
Commercial Portfolio | Commercial and multifamily real estate | Interest Rate Reduction and Term Extension
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Commercial Portfolio | Commercial and multifamily real estate | Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	54	54
Commercial Portfolio | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 193	$ 400
Financing Receivable, Modified in Period, to Total Financing Receivables, Percentage	0.35%	0.72%
Commercial Portfolio | Commercial and industrial | Interest Rate Reduction
Financing Receivable, Past Due [Line Items]
Weighted-average interest rate reduction	0.00%	0.00%
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0	$ 0
Commercial Portfolio | Commercial and industrial | Term Extension
Financing Receivable, Past Due [Line Items]
Payment delay duration (in months)	4 months	6 months
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 172	$ 237
Commercial Portfolio | Commercial and industrial | Principal Forgiveness [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Commercial Portfolio | Commercial and industrial | Extended Maturity and Principal Forgiveness [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount		17
Commercial Portfolio | Commercial and industrial | Interest Rate Reduction and Term Extension
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Commercial Portfolio | Commercial and industrial | Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 21	$ 146