Loans - Credit Card Delinquency Status (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Financing Receivable, Allowance for Credit Loss [Line Items]
Total	$ 303,943	$ 277,340
Credit Card
Financing Receivable, Allowance for Credit Loss [Line Items]
Revolving loans	126,573	114,361
Revolving loans converted to term	340	411
Total	126,913	114,772
Domestic credit card: | Credit Card
Financing Receivable, Allowance for Credit Loss [Line Items]
Revolving loans	120,978	108,364
Revolving loans converted to term	301	359
Total	121,279	108,723
International card businesses: | Credit Card
Financing Receivable, Allowance for Credit Loss [Line Items]
Revolving loans	5,595	5,997
Revolving loans converted to term	39	52
Total	5,634	6,049
Current | Domestic credit card: | Credit Card
Financing Receivable, Allowance for Credit Loss [Line Items]
Revolving loans	117,410	105,985
Revolving loans converted to term	266	327
Total	117,676	106,312
Current | International card businesses: | Credit Card
Financing Receivable, Allowance for Credit Loss [Line Items]
Revolving loans	5,379	5,795
Revolving loans converted to term	30	41
Total	5,409	5,836
30-59 days | Domestic credit card: | Credit Card
Financing Receivable, Allowance for Credit Loss [Line Items]
Revolving loans	1,165	760
Revolving loans converted to term	14	13
Total	1,179	773
30-59 days | International card businesses: | Credit Card
Financing Receivable, Allowance for Credit Loss [Line Items]
Revolving loans	76	73
Revolving loans converted to term	3	4
Total	79	77
60-89 days | Domestic credit card: | Credit Card
Financing Receivable, Allowance for Credit Loss [Line Items]
Revolving loans	808	519
Revolving loans converted to term	9	9
Total	817	528
60-89 days | International card businesses: | Credit Card
Financing Receivable, Allowance for Credit Loss [Line Items]
Revolving loans	50	47
Revolving loans converted to term	3	3
Total	53	50
Greater than 90 days | Domestic credit card: | Credit Card
Financing Receivable, Allowance for Credit Loss [Line Items]
Revolving loans	1,595	1,100
Revolving loans converted to term	12	10
Total	1,607	1,110
Greater than 90 days | International card businesses: | Credit Card
Financing Receivable, Allowance for Credit Loss [Line Items]
Revolving loans	90	82
Revolving loans converted to term	3	4
Total	$ 93	$ 86