Loans - 90+ Day Delinquent Loans Accruing Interest and Nonperforming Loans (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Financing Receivable, Past Due [Line Items]
90 Days Past Due and Accruing	$ 2,491		$ 2,491		$ 2,240
Nonperforming Loans	1,452		1,452		1,344
Nonperforming Loans Without an Allowance	$ 540		$ 540		$ 548
Percentage, 90 Days Past Due and Accruing	0.80%		0.80%		0.72%
Percentage, Nonperforming Loans	0.47%		0.47%		0.43%
Percentage, Nonperforming Loans Without an Allowance	0.17%		0.17%		0.18%
Interest income for loans classified as nonperforming	$ 5	$ 1	$ 17	$ 11
Credit Card:
Financing Receivable, Past Due [Line Items]
90 Days Past Due and Accruing	2,491		2,491		$ 2,240
Nonperforming Loans	10		10		9
Nonperforming Loans Without an Allowance	0		0		0
Credit Card: | Domestic credit card:
Financing Receivable, Past Due [Line Items]
90 Days Past Due and Accruing	2,375		2,375		2,135
Nonperforming Loans Without an Allowance	0		0		0
Credit Card: | International card businesses:
Financing Receivable, Past Due [Line Items]
90 Days Past Due and Accruing	116		116		105
Nonperforming Loans	10		10		9
Nonperforming Loans Without an Allowance	0		0		0
Consumer Banking:
Financing Receivable, Past Due [Line Items]
90 Days Past Due and Accruing	0		0		0
Nonperforming Loans	631		631		634
Nonperforming Loans Without an Allowance	19		19		8
Consumer Banking: | Auto
Financing Receivable, Past Due [Line Items]
90 Days Past Due and Accruing	0		0		0
Nonperforming Loans	588		588		595
Nonperforming Loans Without an Allowance	0		0		0
Consumer Banking: | Retail banking
Financing Receivable, Past Due [Line Items]
90 Days Past Due and Accruing	0		0		0
Nonperforming Loans	43		43		39
Nonperforming Loans Without an Allowance	19		19		8
Commercial Portfolio
Financing Receivable, Past Due [Line Items]
90 Days Past Due and Accruing	0		0		0
Nonperforming Loans	811		811		701
Nonperforming Loans Without an Allowance	521		521		540
Commercial Portfolio | Commercial and multifamily real estate
Financing Receivable, Past Due [Line Items]
90 Days Past Due and Accruing	0		0		0
Nonperforming Loans	416		416		271
Nonperforming Loans Without an Allowance	303		303		246
Commercial Portfolio | Commercial and industrial
Financing Receivable, Past Due [Line Items]
90 Days Past Due and Accruing	0		0		0
Nonperforming Loans	395		395		430
Nonperforming Loans Without an Allowance	$ 218		$ 218		$ 294