Income Taxes - Income Tax Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current
Domestic	$ 102	$ 593	$ 6,204
Foreign	320	434	376
Total current taxes	422	1,027	6,580
Deferred
Domestic	(137)	(1,497)	(4,898)
Foreign	259	(20)	736
Total deferred taxes	122	(1,517)	(4,162)
Total income tax expense (benefit)	$ 544	$ (490)	$ 2,418