Income Taxes - Components of Income Tax Expense/(Benefit) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current income tax expense/(benefit)
U.S. federal	$ 2,854	$ 5,718	$ 2,488
Non-U.S.	2,077	2,400	1,760
U.S. state and local	1,638	1,029	904
Total current income tax expense/(benefit)	6,569	9,147	5,152
Deferred income tax expense/(benefit)
U.S. federal	1,359	2,174	4,364
Non-U.S.	(93)	(144)	(73)
U.S. state and local	455	282	360
Total deferred income tax expense/(benefit)	1,721	2,312	4,651
Total income tax expense	8,290	11,459	9,803
Components of income tax expense/(benefit), supplemental information
Tax benefits recorded as a result of tax audit resolutions	54	252	55
Increase (decrease) to income tax allocated directly to equity	$ 172	$ (915)	$ 925