Loans - 90+ Day Delinquent Loans Accruing Interest and Nonperforming Loans (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Financing Receivable, Past Due [Line Items]
90 Days Past Due and Accruing	$ 1,700		$ 1,700		$ 1,195
Nonperforming Loans	1,075		1,075		1,100
Nonperforming Loans Without an Allowance	$ 424		$ 424		$ 529
Percentage, 90 Days Past Due and Accruing	0.56%		0.56%		0.43%
Percentage, Nonperforming Loans	0.35%		0.35%		0.40%
Percentage, Nonperforming Loans Without an Allowance	0.14%		0.14%		0.19%
Interest income for loans classified as nonperforming	$ 2	$ 1	$ 29	$ 21
Credit Card
Financing Receivable, Past Due [Line Items]
90 Days Past Due and Accruing	1,697		1,697		$ 1,192
Nonperforming Loans	8		8		10
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	1,607		1,607		1,110
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	90		90		82
Nonperforming Loans	8		8		10
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	517		517		391
Nonperforming Loans Without an Allowance	5		5		4
Consumer Banking | Auto
Financing Receivable, Past Due [Line Items]
90 Days Past Due and Accruing	0		0		0
Nonperforming Loans	474		474		344
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		47
Nonperforming Loans Without an Allowance	5		5		4
Commercial Banking
Financing Receivable, Past Due [Line Items]
90 Days Past Due and Accruing	3		3		3
Nonperforming Loans	550		550		699
Nonperforming Loans Without an Allowance	419		419		525
Commercial Banking | Commercial and multifamily real estate
Financing Receivable, Past Due [Line Items]
90 Days Past Due and Accruing	3		3		3
Nonperforming Loans	243		243		383
Nonperforming Loans Without an Allowance	219		219		268
Commercial Banking | Commercial And Industrial [Member]
Financing Receivable, Past Due [Line Items]
90 Days Past Due and Accruing	0		0		0
Nonperforming Loans	307		307		316
Nonperforming Loans Without an Allowance	$ 200		$ 200		$ 257