Business Segments and Revenue from Contracts with Customers - Segment Results and Reconciliation (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Segment Reporting Information [Line Items]
Net interest income (loss)	$ 7,186	$ 6,397
Non-interest income	1,717	1,776
Total net revenue (loss)	8,903	8,173
Change in estimated partner reimbursements that decreased/(increased) provision for credit losses	2,795	677
Non-interest expense	4,945	4,551
Income (loss) from continuing operations before income taxes	1,163	2,945
Income tax provision (benefit)	203	542
Income (loss) from continuing operations, net of tax	960	2,403
Total loans held for investment	308,836	280,466	$ 312,331
Total Deposits	349,827	313,429	$ 332,992
Uncollectible portion of billed finance charges and fees	405	192
Operating segments | Credit Card
Segment Reporting Information [Line Items]
Net interest income (loss)	4,657	3,839
Non-interest income	1,363	1,458
Total net revenue (loss)	6,020	5,297
Change in estimated partner reimbursements that decreased/(increased) provision for credit losses	2,261	545
Non-interest expense	3,038	2,783
Income (loss) from continuing operations before income taxes	721	1,969
Income tax provision (benefit)	172	469
Income (loss) from continuing operations, net of tax	549	1,500
Total loans held for investment	137,142	113,962
Total Deposits	0	0
Operating segments | Consumer Banking
Segment Reporting Information [Line Items]
Net interest income (loss)	2,360	2,113
Non-interest income	135	105
Total net revenue (loss)	2,495	2,218
Change in estimated partner reimbursements that decreased/(increased) provision for credit losses	275	130
Non-interest expense	1,283	1,236
Income (loss) from continuing operations before income taxes	937	852
Income tax provision (benefit)	221	202
Income (loss) from continuing operations, net of tax	716	650
Total loans held for investment	78,151	80,330
Total Deposits	291,163	258,359
Operating segments | Commercial Banking
Segment Reporting Information [Line Items]
Net interest income (loss)	648	607
Non-interest income	212	277
Total net revenue (loss)	860	884
Change in estimated partner reimbursements that decreased/(increased) provision for credit losses	259	8
Non-interest expense	530	488
Income (loss) from continuing operations before income taxes	71	388
Income tax provision (benefit)	17	92
Income (loss) from continuing operations, net of tax	54	296
Total loans held for investment	93,543	86,174
Total Deposits	38,380	45,232
Other
Segment Reporting Information [Line Items]
Net interest income (loss)	(479)	(162)
Non-interest income	7	(64)
Total net revenue (loss)	(472)	(226)
Change in estimated partner reimbursements that decreased/(increased) provision for credit losses	0	(6)
Non-interest expense	94	44
Income (loss) from continuing operations before income taxes	(566)	(264)
Income tax provision (benefit)	(207)	(221)
Income (loss) from continuing operations, net of tax	(359)	(43)
Total loans held for investment	0	0
Total Deposits	$ 20,284	$ 9,838