Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current income tax expense:
U.S. federal	$ 1,122	$ 1,108	$ 70
U.S. state and local	339	276	150
Non-U.S.	639	437	681
Total current income tax expense	2,100	1,821	901
Deferred income tax expense (benefit):
U.S. federal	(931)	(58)	276
U.S. state and local	(119)	(31)	78
Non-U.S.	111	(62)	(54)
Total deferred income tax expense	(939)	(151)	300
Income tax provision (benefit)	$ 1,161	$ 1,670	$ 1,201