Reportable Operating Segments (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025	Dec. 31, 2025
Segment Reporting [Line Items]
Number of reportable segments not disclosed flag			segments
Total non-interest revenues	$ 15,122	$ 13,940	$ 44,324	$ 40,407
Revenue from contracts with customers	11,232	10,415	32,962	30,362
Interest income	6,858	6,617	20,129	19,016
Interest expense	1,918	2,131	5,847	6,174
Net interest income	4,940	4,486	14,282	12,842
Total revenues net of interest expense	20,062	18,426	58,606	53,249
Provisions for credit losses	985	1,287	3,320	3,842
Total revenues net of interest expense after provisions for credit losses	19,077	17,139	55,286	49,407
Card Member rewards, business development and Card Member services	8,891	7,696	26,102	22,439
Marketing	1,770	1,599	4,900	4,640
Salaries and employee benefits and other operating expenses	3,885	4,019	11,904	11,623
Total expenses	14,546	13,314	42,906	38,702
Pretax income	4,531	3,825	12,380	10,705
Total assets	310,275	297,550	310,275	297,550	$ 300,052
Operating Segments
Segment Reporting [Line Items]
Total non-interest revenues	15,151	13,877	44,350	40,358
Revenue from contracts with customers	11,242	10,425	32,992	30,388
Interest income	6,404	5,988	18,694	17,226
Interest expense	1,397	1,420	4,166	4,174
Net interest income	5,006	4,568	14,529	13,052
Total revenues net of interest expense	20,158	18,445	58,878	53,410
Provisions for credit losses	985	1,289	3,320	3,843
Total revenues net of interest expense after provisions for credit losses	19,173	17,156	55,558	49,567
Card Member rewards, business development and Card Member services	8,883	7,685	26,081	22,405
Marketing	1,760	1,593	4,876	4,620
Salaries and employee benefits and other operating expenses	3,692	3,455	10,654	10,080
Total expenses	14,335	12,733	41,611	37,105
Pretax income	4,838	4,423	13,947	12,462
Total assets	262,848	245,767	262,848	245,767
Corporate and Other
Segment Reporting [Line Items]
Total non-interest revenues	(30)	63	(25)	49
Revenue from contracts with customers	(10)	(10)	(30)	(26)
Interest income	454	629	1,435	1,790
Interest expense	520	711	1,682	2,000
Net interest income	(66)	(82)	(247)	(210)
Total revenues net of interest expense	(96)	(19)	(272)	(161)
Provisions for credit losses	0	(2)	0	(1)
Total revenues net of interest expense after provisions for credit losses	(96)	(17)	(272)	(160)
Card Member rewards, business development and Card Member services	8	11	21	34
Marketing	10	6	24	20
Salaries and employee benefits and other operating expenses	193	564	1,249	1,543
Total expenses	211	581	1,294	1,597
Pretax income	(307)	(598)	(1,566)	(1,757)
Total assets	47,427	51,783	47,427	51,783
USCS | Operating Segments
Segment Reporting [Line Items]
Total non-interest revenues	6,292	5,620	18,323	16,403
Revenue from contracts with customers	4,336	3,925	12,670	11,462
Interest income	4,294	4,025	12,417	11,583
Interest expense	745	789	2,253	2,328
Net interest income	3,549	3,236	10,164	9,255
Total revenues net of interest expense	9,840	8,856	28,487	25,658
Provisions for credit losses	494	734	1,623	2,194
Total revenues net of interest expense after provisions for credit losses	9,346	8,122	26,864	23,464
Card Member rewards, business development and Card Member services	4,801	4,145	14,151	11,994
Marketing	848	825	2,425	2,390
Salaries and employee benefits and other operating expenses	1,402	1,300	4,172	3,820
Total expenses	7,052	6,270	20,748	18,204
Pretax income	2,295	1,852	6,116	5,260
Total assets	124,624	115,330	124,624	115,330
CS | Operating Segments
Segment Reporting [Line Items]
Total non-interest revenues	3,612	3,441	10,611	10,128
Revenue from contracts with customers	3,106	2,986	9,134	8,789
Interest income	1,358	1,302	4,046	3,744
Interest expense	416	462	1,280	1,344
Net interest income	942	840	2,766	2,400
Total revenues net of interest expense	4,553	4,281	13,377	12,528
Provisions for credit losses	279	332	1,012	1,021
Total revenues net of interest expense after provisions for credit losses	4,274	3,949	12,365	11,507
Card Member rewards, business development and Card Member services	1,979	1,730	5,959	5,266
Marketing	405	313	1,095	981
Salaries and employee benefits and other operating expenses	860	816	2,495	2,429
Total expenses	3,245	2,859	9,549	8,676
Pretax income	1,029	1,090	2,815	2,831
Total assets	66,006	64,305	66,006	64,305
ICS | Operating Segments
Segment Reporting [Line Items]
Total non-interest revenues	3,321	3,034	9,746	8,627
Revenue from contracts with customers	2,072	1,928	6,099	5,492
Interest income	745	652	2,205	1,868
Interest expense	383	350	1,118	991
Net interest income	362	302	1,087	877
Total revenues net of interest expense	3,682	3,336	10,833	9,504
Provisions for credit losses	208	218	668	620
Total revenues net of interest expense after provisions for credit losses	3,474	3,118	10,165	8,884
Card Member rewards, business development and Card Member services	1,766	1,512	5,000	4,276
Marketing	394	350	1,078	972
Salaries and employee benefits and other operating expenses	883	815	2,397	2,349
Total expenses	3,042	2,677	8,474	7,597
Pretax income	432	441	1,690	1,287
Total assets	52,809	47,253	52,809	47,253
GMNS | Operating Segments
Segment Reporting [Line Items]
Total non-interest revenues	1,927	1,782	5,670	5,200
Revenue from contracts with customers	1,729	1,586	5,088	4,645
Interest income	7	9	26	31
Interest expense	(147)	(181)	(486)	(489)
Net interest income	155	190	512	520
Total revenues net of interest expense	2,082	1,972	6,182	5,720
Provisions for credit losses	4	5	18	8
Total revenues net of interest expense after provisions for credit losses	2,078	1,967	6,164	5,712
Card Member rewards, business development and Card Member services	337	298	971	869
Marketing	113	105	278	277
Salaries and employee benefits and other operating expenses	546	524	1,590	1,482
Total expenses	996	927	2,839	2,628
Pretax income	1,082	1,040	3,325	3,084
Total assets	$ 19,409	$ 18,879	$ 19,409	$ 18,879