Income Taxes - Components of Income Tax Expense/(Benefit) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current income tax expense/(benefit)
U.S. federal	$ 5,759	$ 3,284	$ 2,854
Non-U.S.	2,705	2,103	2,077
U.S. state and local	1,793	1,778	1,638
Total current income tax expense/(benefit)	10,257	7,165	6,569
Deferred income tax expense/(benefit)
U.S. federal	(3,184)	709	1,359
Non-U.S.	(126)	20	(93)
U.S. state and local	(671)	220	455
Total deferred income tax expense/(benefit)	(3,981)	949	1,721
Total income tax expense	6,276	8,114	8,290
Components of income tax expense/(benefit), supplemental information
Tax benefits recorded as a result of tax audit resolutions	72	1,100	54
Increase (decrease) to income tax allocated directly to equity	$ (827)	$ (862)	$ 172