Business Segments and Revenue from Contracts with Customers - Segment Results and Reconciliation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Net interest income (loss)	$ 24,171	$ 22,913	$ 23,340
Non-interest income (loss)	6,264	5,610	5,253
Total net revenue (loss)	30,435	28,523	28,593
Provision (benefit) for credit losses	(1,944)	10,264	6,236
Non-interest expense	16,570	15,056	15,483
Income (loss) from continuing operations before income taxes	15,809	3,203	6,874
Income tax provision	3,415	486	1,341
Income (loss) from continuing operations, net of tax	12,394	2,717	5,533
Total loans held for investment	277,340	251,624	265,809
Total Deposits	310,980	305,442	262,697
Uncollectible portion of billed finance charges and fees	629	1,100	1,400
Operating segments | Credit Card
Segment Reporting Information [Line Items]
Net interest income (loss)	14,074	13,776	14,461
Non-interest income (loss)	4,806	3,823	3,888
Total net revenue (loss)	18,880	17,599	18,349
Provision (benefit) for credit losses	(902)	7,327	4,992
Non-interest expense	9,621	8,491	9,271
Income (loss) from continuing operations before income taxes	10,161	1,781	4,086
Income tax provision	2,403	420	959
Income (loss) from continuing operations, net of tax	7,758	1,361	3,127
Total loans held for investment	114,772	106,956	128,236
Total Deposits	0	0	0
Operating segments | Consumer Banking
Segment Reporting Information [Line Items]
Net interest income (loss)	8,448	7,238	6,732
Non-interest income (loss)	554	466	643
Total net revenue (loss)	9,002	7,704	7,375
Provision (benefit) for credit losses	(521)	1,753	938
Non-interest expense	4,711	4,159	4,091
Income (loss) from continuing operations before income taxes	4,812	1,792	2,346
Income tax provision	1,136	425	547
Income (loss) from continuing operations, net of tax	3,676	1,367	1,799
Total loans held for investment	77,646	68,888	63,065
Total Deposits	256,407	249,815	213,099
Operating segments | Commercial Banking
Segment Reporting Information [Line Items]
Net interest income (loss)	2,153	2,048	1,983
Non-interest income (loss)	1,148	923	831
Total net revenue (loss)	3,301	2,971	2,814
Provision (benefit) for credit losses	(519)	1,181	306
Non-interest expense	1,815	1,706	1,699
Income (loss) from continuing operations before income taxes	2,005	84	809
Income tax provision	473	19	188
Income (loss) from continuing operations, net of tax	1,532	65	621
Total loans held for investment	84,922	75,780	74,508
Total Deposits	44,809	39,590	32,134
Other
Segment Reporting Information [Line Items]
Net interest income (loss)	(504)	(149)	164
Non-interest income (loss)	(244)	398	(109)
Total net revenue (loss)	(748)	249	55
Provision (benefit) for credit losses	(2)	3	0
Non-interest expense	423	700	422
Income (loss) from continuing operations before income taxes	(1,169)	(454)	(367)
Income tax provision	(597)	(378)	(353)
Income (loss) from continuing operations, net of tax	(572)	(76)	(14)
Total loans held for investment	0	0	0
Total Deposits	$ 9,764	$ 16,037	$ 17,464