Income Taxes - Components of Income Tax Expense/(Benefit) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current income tax expense/(benefit)
U.S. federal	$ 2,488	$ 3,160	$ 2,382
Non-U.S.	1,760	1,220	1,353
U.S. state and local	904	547	857
Total current income tax expense/(benefit)	5,152	4,927	4,592
Deferred income tax expense/(benefit)
U.S. federal	4,364	1,213	3,890
Non-U.S.	(73)	(95)	71
U.S. state and local	360	215	401
Total deferred income tax expense/(benefit)	4,651	1,333	4,362
Total income tax expense	9,803	6,260	8,954
Components of income tax expense/(benefit), supplemental information
Tax benefits recorded as a result of tax audit resolutions	55	2,400	451
Income tax effects allocated directly to equity	$ 925	$ 1,500	$ (140)