Reportable Operating Segements and Geographic Operations (Details 1) - 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 Revenues And Pretax Income Loss By Geographic Location [Line Items]
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
Pretax income	$ 1,831	$ 2,118	$ 2,091	$ 2,082	$ 1,798	$ 1,831	$ 1,957	$ 1,839	8,122	7,425	8,042
U.S. Tax Act Discrete Net Charge									(100)	2,600
United States Geographic Region [Member]
Segment Revenues And Pretax Income Loss By Geographic Location [Line Items]
Total revenues net of interest expense									29,864	27,187	26,339
Pretax income									6,696	6,412	7,943
EMEA Geographic Region [Member]
Segment Revenues And Pretax Income Loss By Geographic Location [Line Items]
Total revenues net of interest expense									4,419	3,927	3,570
Pretax income									1,212	1,150	698
JAPA Geographic Region [Member]
Segment Revenues And Pretax Income Loss By Geographic Location [Line Items]
Total revenues net of interest expense									3,656	3,464	3,275
Pretax income									764	763	556
LACC Geographic Region [Member]
Segment Revenues And Pretax Income Loss By Geographic Location [Line Items]
Total revenues net of interest expense									2,584	2,505	2,360
Pretax income									782	806	635
Other Unallocated [Member]
Segment Revenues And Pretax Income Loss By Geographic Location [Line Items]
Total revenues net of interest expense									(185)	(205)	(106)
Pretax income									$ (1,332)	$ (1,706)	$ (1,790)