Loans - TDR - Subsequent Defaults (Details) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2022 USD ($) contract	Jun. 30, 2022 USD ($) contract
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | contract	31,164	55,655
Total Loans | $	$ 104	$ 198
Credit Card:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | contract	27,623	50,142
Total Loans | $	$ 37	$ 67
Consumer Banking:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | contract	3,539	5,510
Total Loans | $	$ 63	$ 96
Consumer Banking: | Auto
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | contract	3,539	5,510
Total Loans | $	$ 63	$ 96
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	2	3
Total Loans | $	$ 4	$ 35
Commercial Portfolio | Commercial and industrial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | contract	2	3
Total Loans | $	$ 4	$ 35
Domestic credit card: | Credit Card:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | contract	8,012	14,024
Total Loans | $	$ 17	$ 28
International card businesses: | Credit Card:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | contract	19,611	36,118
Total Loans | $	$ 20	$ 39