Income Taxes - Summary of Provision for Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current income tax expense:
Federal	$ 76	$ 186	$ 12
State	20	42	6
Foreign	198	167	130
Current income tax expense	294	395	148
Deferred income tax (benefit) expense:
Federal	(53)	(273)	(94)
State	(9)	(25)	(1)
Foreign	(29)	(10)	(8)
Deferred income tax (benefit) expense	(91)	(308)	(103)
Income tax expense	$ 203	$ 87	$ 45