Reportable Operating Segments and Geographic Operations (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Non-interest revenues									$ 27,030	$ 26,348	$ 26,896
Interest income									8,553	7,475	7,545
Interest expense									2,112	1,704	1,623
Total revenues, net of interest expense	$ 8,839	$ 8,436	$ 8,307	$ 7,889	$ 8,022	$ 7,774	$ 8,235	$ 8,088	33,471	32,119	32,818
Total provision									2,759	2,026	1,988
Pretax income	1,821	$ 1,827	$ 1,949	$ 1,817	1,161	$ 1,735	$ 3,016	$ 2,184	7,414	8,096	7,938
Income tax provision (benefit)									4,678	2,688	2,775
Net Income from continuing operations									2,736	5,408	5,163
Total assets	181,159				158,893				181,159	158,893	161,000
U S Consumer Services [Member]
Segment Reporting Information [Line Items]
Non-interest revenues									7,923	7,874	8,479
Interest income									5,755	5,082	5,198
Interest expense									742	536	488
Total revenues, net of interest expense									12,936	12,420	13,189
Total provision									1,630	1,065	1,064
Pretax income									2,803	3,881	3,677
Income tax provision (benefit)									912	1,368	1,322
Net Income from continuing operations									1,891	2,513	2,355
Total assets	94,200				87,400				94,200	87,400	92,700
International Consumer and Network Services [Member]
Segment Reporting Information [Line Items]
Non-interest revenues									5,052	4,785	4,627
Interest income									1,029	922	945
Interest expense									251	219	235
Total revenues, net of interest expense									5,830	5,488	5,337
Total provision									367	325	300
Pretax income									1,093	818	904
Income tax provision (benefit)									181	163	220
Net Income from continuing operations									912	655	684
Total assets	38,900				35,700				38,900	35,700	35,100
Global Commercial Services [Member]
Segment Reporting Information [Line Items]
Non-interest revenues									9,463	9,007	8,930
Interest income									1,361	1,209	1,175
Interest expense									540	401	365
Total revenues, net of interest expense									10,284	9,815	9,740
Total provision									744	604	588
Pretax income									2,999	2,945	3,164
Income tax provision (benefit)									972	1,036	1,142
Net Income from continuing operations									2,027	1,909	2,022
Total assets	52,600				46,500				52,600	46,500	45,100
Global Merchant Services [Member]
Segment Reporting Information [Line Items]
Non-interest revenues									4,333	4,235	4,471
Interest income									1	1	1
Interest expense									(262)	(237)	(211)
Total revenues, net of interest expense									4,596	4,473	4,683
Total provision									15	25	31
Pretax income									2,389	2,295	2,381
Income tax provision (benefit)									815	837	882
Net Income from continuing operations									1,574	1,458	1,499
Total assets	29,000				24,300				29,000	24,300	23,500
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Non-interest revenues									259	447	389
Interest income									407	261	226
Interest expense									841	785	746
Total revenues, net of interest expense									(175)	(77)	(131)
Total provision									3	7	5
Pretax income									(1,870)	(1,843)	(2,188)
Income tax provision (benefit)									1,798	(716)	(791)
Net Income from continuing operations									(3,668)	(1,127)	(1,397)
Total assets	$ (33,700)				$ (34,900)				$ (33,700)	$ (34,900)	$ (36,400)