Income Taxes - Income Tax Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current taxes
U.S. income taxes	$ 1,476	$ 804	$ 974
Foreign income taxes	173	185	122
State income taxes	114	47	36
Total taxes, current	1,763	1,036	1,132
Deferred taxes (benefits)
U.S. Income taxes (benefits)	(236)	(75)	204
Foreign income taxes (benefits)	16	8	39
State income taxes (benefits)	(93)	(34)	(1)
Total taxes (benefits), deferred	(313)	(101)	242
Total income taxes	$ 1,450	$ 935	$ 1,374