Loans - 90+ Day Delinquent Loans Accruing Interest and Nonperforming Loans (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Financing Receivable, Past Due [Line Items]
90 Days Past Due and Accruing	$ 1,294		$ 1,195
Nonperforming Loans	1,073		1,100
Nonperforming Loans Without an Allowance	$ 456		$ 529
Percentage, 90 Days Past Due and Accruing	0.46%		0.43%
Percentage, Nonperforming Loans	0.38%		0.40%
Percentage, Nonperforming Loans Without an Allowance	0.16%		0.19%
Interest income for loans classified as nonperforming	$ 1	$ 1
Credit Card
Financing Receivable, Past Due [Line Items]
90 Days Past Due and Accruing	1,282		$ 1,192
Nonperforming Loans	8		10
Nonperforming Loans Without an Allowance	0		0
Credit Card \| Domestic credit card:
Financing Receivable, Past Due [Line Items]
90 Days Past Due and Accruing	1,191		1,110
Nonperforming Loans Without an Allowance	0		0
Credit Card \| International card businesses:
Financing Receivable, Past Due [Line Items]
90 Days Past Due and Accruing	91		82
Nonperforming Loans	8		10
Nonperforming Loans Without an Allowance	0		0
Consumer Banking
Financing Receivable, Past Due [Line Items]
90 Days Past Due and Accruing	0		0
Nonperforming Loans	370		391
Nonperforming Loans Without an Allowance	0		4
Consumer Banking \| Auto
Financing Receivable, Past Due [Line Items]
90 Days Past Due and Accruing	0		0
Nonperforming Loans	325		344
Nonperforming Loans Without an Allowance	0		0
Consumer Banking \| Retail banking
Financing Receivable, Past Due [Line Items]
90 Days Past Due and Accruing	0		0
Nonperforming Loans	45		47
Nonperforming Loans Without an Allowance	0		4
Commercial Banking
Financing Receivable, Past Due [Line Items]
90 Days Past Due and Accruing	12		3
Nonperforming Loans	695		699
Nonperforming Loans Without an Allowance	456		525
Commercial Banking \| Commercial And Industrial [Member]
Financing Receivable, Past Due [Line Items]
90 Days Past Due and Accruing	0		0
Nonperforming Loans	360		316
Nonperforming Loans Without an Allowance	235		257
Commercial Banking \| Commercial and multifamily real estate
Financing Receivable, Past Due [Line Items]
90 Days Past Due and Accruing	12		3
Nonperforming Loans	335		383
Nonperforming Loans Without an Allowance	$ 221		$ 268

Financing Receivable, Nonaccrual, No Allowance, Percent Past Due

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Financing Receivable, Percent 90 Days Past Due and Still Accruing

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Amount of interest income on financing receivable on nonaccrual status.

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Amount of financing receivable on nonaccrual status with no allowance for credit loss.

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Percentage of nonaccrual financing receivable balance outstanding that is past due.

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Amount of financing receivable 90 days or more past due and still accruing.

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Amount of financing receivable on nonaccrual status.

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