Reportable Operating Segments and Geographic Operations (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Non-interest revenues									$ 34,936	$ 32,675	$ 30,427
Revenue from contracts with customers									28,159	26,607	24,780
Interest income									12,084	10,606	8,563
Interest expense									3,464	2,943	2,112
Total revenues, net of interest expense	$ 11,365	$ 10,989	$ 10,838	$ 10,364	$ 10,474	$ 10,144	$ 10,002	$ 9,718	43,556	40,338	36,878
Total provisions									3,573	3,352	2,760
Pretax income	1,986	2,266	2,219	1,958	1,831	2,118	2,091	2,082	8,429	8,122	7,425
Income tax provision (benefit)									1,670	1,201	4,677
Net income	1,693	$ 1,755	$ 1,761	$ 1,550	2,010	$ 1,654	$ 1,623	$ 1,634	6,759	6,921	2,748
Total assets	198,321				188,602				198,321	188,602	181,000
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Non-interest revenues									89	49	82
Revenue from contracts with customers									12	16	15
Interest income									743	632	371
Interest expense									1,028	868	658
Total revenues, net of interest expense									(196)	(187)	(205)
Total provisions									0	1	5
Pretax income									(1,809)	(1,331)	(1,708)
Income tax provision (benefit)									(418)	(695)	1,853
Net income									(1,391)	(636)	(3,561)
Total assets	21,000				20,000				21,000	20,000	17,000
Global Consumer Services Group [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Non-interest revenues									15,972	14,675	13,378
Revenue from contracts with customers									11,041	10,294	9,448
Interest income									9,413	8,323	6,789
Interest expense									1,806	1,542	1,047
Total revenues, net of interest expense									23,579	21,456	19,120
Total provisions									2,636	2,430	1,996
Pretax income									4,024	3,714	3,645
Income tax provision (benefit)									762	637	1,053
Net income									3,262	3,077	2,592
Total assets	106,000				102,000				106,000	102,000	95,000
Global Commercial Services [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Non-interest revenues									12,623	11,882	10,942
Revenue from contracts with customers									10,891	10,309	9,471
Interest income									1,900	1,621	1,361
Interest expense									995	827	595
Total revenues, net of interest expense									13,528	12,676	11,708
Total provisions									917	899	743
Pretax income									3,066	2,895	2,843
Income tax provision (benefit)									590	555	914
Net income									2,476	2,340	1,929
Total assets	53,000				51,000				53,000	51,000	49,000
Global Merchant and Network Services [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Non-interest revenues									6,252	6,069	6,025
Revenue from contracts with customers									6,215	5,988	5,846
Interest income									28	30	42
Interest expense									(365)	(294)	(188)
Total revenues, net of interest expense									6,645	6,393	6,255
Total provisions									20	22	16
Pretax income									3,148	2,844	2,645
Income tax provision (benefit)									736	704	857
Net income									2,412	2,140	1,788
Total assets	$ 18,000				$ 16,000				$ 18,000	$ 16,000	$ 20,000