Income Taxes - Results from Non-U.S. Earnings (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
U.S.	$ 26,904	$ 36,670	$ 33,052
Non-U.S.	8,503	7,875	7,712
Income before income tax expense	$ 35,407	$ 44,545	$ 40,764