Loans - TDR - Subsequent Defaults (Details) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2022 USD ($) contract	Sep. 30, 2022 USD ($) contract
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | contract	33,490	89,145
Total Loans | $	$ 120	$ 318
Credit Card:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | contract	28,898	79,040
Total Loans | $	$ 38	$ 105
Consumer Banking:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | contract	4,592	10,102
Total Loans | $	$ 82	$ 178
Consumer Banking: | Auto
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | contract	4,592	10,102
Total Loans | $	$ 82	$ 178
Consumer Banking: | Retail banking
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | contract	0	0
Total Loans | $	$ 0	$ 0
Commercial Portfolio
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | contract	0	3
Total Loans | $	$ 0	$ 35
Commercial Portfolio | Commercial and industrial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | contract	0	3
Total Loans | $	$ 0	$ 35
Domestic credit card: | Credit Card:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | contract	9,927	23,951
Total Loans | $	$ 19	$ 47
International card businesses: | Credit Card:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | contract	18,971	55,089
Total Loans | $	$ 19	$ 58