Business Segments and Revenue from Contracts with Customers - Revenue from Contracts with Customers (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disaggregation of Revenue [Line Items]
Total contract revenue	$ 5,417	$ 4,780	$ 3,737
Revenue (reduction) from other sources	1,719	1,484	1,873
Non-interest income (loss)	7,136	6,264	5,610
Operating segments | Credit Card
Disaggregation of Revenue [Line Items]
Total contract revenue	4,573	3,880	3,062
Revenue (reduction) from other sources	1,198	926	761
Non-interest income (loss)	5,771	4,806	3,823
Operating segments | Consumer Banking
Disaggregation of Revenue [Line Items]
Total contract revenue	485	513	436
Revenue (reduction) from other sources	(16)	41	30
Non-interest income (loss)	469	554	466
Operating segments | Commercial Banking
Disaggregation of Revenue [Line Items]
Total contract revenue	361	388	242
Revenue (reduction) from other sources	768	760	681
Non-interest income (loss)	1,129	1,148	923
Other
Disaggregation of Revenue [Line Items]
Total contract revenue	(2)	(1)	(3)
Revenue (reduction) from other sources	(231)	(243)	401
Non-interest income (loss)	(233)	(244)	398
Interchange fees, net
Disaggregation of Revenue [Line Items]
Total contract revenue	4,606	3,860	3,017
Customer reward expenses	7,600	6,400	4,900
Interchange fees, net | Operating segments | Credit Card
Disaggregation of Revenue [Line Items]
Total contract revenue	4,178	3,497	2,747
Interchange fees, net | Operating segments | Consumer Banking
Disaggregation of Revenue [Line Items]
Total contract revenue	320	267	209
Interchange fees, net | Operating segments | Commercial Banking
Disaggregation of Revenue [Line Items]
Total contract revenue	109	96	63
Interchange fees, net | Other
Disaggregation of Revenue [Line Items]
Total contract revenue	(1)	0	(2)
Service charges and other customer-related fees
Disaggregation of Revenue [Line Items]
Total contract revenue	327	457	362
Service charges and other customer-related fees | Operating segments | Credit Card
Disaggregation of Revenue [Line Items]
Total contract revenue	0	0	0
Service charges and other customer-related fees | Operating segments | Consumer Banking
Disaggregation of Revenue [Line Items]
Total contract revenue	91	171	188
Service charges and other customer-related fees | Operating segments | Commercial Banking
Disaggregation of Revenue [Line Items]
Total contract revenue	236	287	175
Service charges and other customer-related fees | Other
Disaggregation of Revenue [Line Items]
Total contract revenue	0	(1)	(1)
Other
Disaggregation of Revenue [Line Items]
Total contract revenue	484	463	358
Other | Operating segments | Credit Card
Disaggregation of Revenue [Line Items]
Total contract revenue	395	383	315
Other | Operating segments | Consumer Banking
Disaggregation of Revenue [Line Items]
Total contract revenue	74	75	39
Other | Operating segments | Commercial Banking
Disaggregation of Revenue [Line Items]
Total contract revenue	16	5	4
Other | Other
Disaggregation of Revenue [Line Items]
Total contract revenue	$ (1)	$ 0	$ 0