Reportable Operating Segments and Geographic Operations (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Non-interest revenues									$ 32,675	$ 30,427	$ 29,659
Interest income									10,606	8,563	7,484
Interest expense									2,943	2,112	1,705
Total revenues, net of interest expense	$ 10,474	$ 10,144	$ 10,002	$ 9,718	$ 9,707	$ 9,290	$ 9,172	$ 8,709	40,338	36,878	35,438
Total provision									3,352	2,760	2,027
Pretax income	1,831	2,118	2,091	2,082	1,798	1,831	1,957	1,839	8,122	7,425	8,042
Income tax provision (benefit)									1,201	4,677	2,667
Net income	2,010	$ 1,654	$ 1,623	$ 1,634	(1,206)	$ 1,359	$ 1,344	$ 1,251	6,921	2,748	5,375
Total assets	188,602				181,196				188,602	181,196	159,000
Revenue from contracts with customers									26,607	24,780	24,235
Global Consumer Services Group [Member]
Segment Reporting Information [Line Items]
Non-interest revenues									14,675	13,378	12,993
Interest income									8,323	6,789	6,005
Interest expense									1,542	1,047	828
Total revenues, net of interest expense									21,456	19,120	18,170
Total provision									2,430	1,996	1,390
Pretax income									3,714	3,645	4,508
Income tax provision (benefit)									637	1,053	1,469
Net income									3,077	2,592	3,039
Total assets	150,700				123,500				150,700	123,500	114,100
Revenue from contracts with customers									10,294	9,448	9,386
Global Commercial Services [Member]
Segment Reporting Information [Line Items]
Non-interest revenues									11,882	10,942	10,373
Interest income									1,621	1,361	1,209
Interest expense									827	595	472
Total revenues, net of interest expense									12,676	11,708	11,110
Total provision									899	743	604
Pretax income									2,895	2,843	2,933
Income tax provision (benefit)									555	914	1,032
Net income									2,340	1,929	1,901
Total assets	51,800				49,100				51,800	49,100	43,300
Revenue from contracts with customers									10,309	9,471	8,918
Global Merchant and Network Services [Member]
Segment Reporting Information [Line Items]
Non-interest revenues									6,069	6,025	6,093
Interest income									30	42	37
Interest expense									(294)	(188)	(133)
Total revenues, net of interest expense									6,393	6,255	6,263
Total provision									22	16	24
Pretax income									2,844	2,645	2,391
Income tax provision (benefit)									704	857	861
Net income									2,140	1,788	1,530
Total assets	44,500				30,600				44,500	30,600	25,800
Revenue from contracts with customers									5,988	5,846	5,826
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Non-interest revenues									49	82	200
Interest income									632	371	233
Interest expense									868	658	538
Total revenues, net of interest expense									(187)	(205)	(105)
Total provision									1	5	9
Pretax income									(1,331)	(1,708)	(1,790)
Income tax provision (benefit)									(695)	1,853	(695)
Net income									(636)	(3,561)	(1,095)
Total assets	$ (59,000)				$ (23,000)				(59,000)	(23,000)	(24,200)
Revenue from contracts with customers									$ 16	$ 15	$ 105