Income Taxes - Schedule of Impact of Tax Cuts and Jobs Act of 2017 (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended		24 Months Ended
	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Transition tax		$ 36
Re-measurement of deferred tax balances		(8)
Indefinite reinvestment assertion		1
Allocation of tax benefit from foreign tax credits		59
Total income tax expense (benefit)		$ 88
Transition tax			$ 264
Re-measurement of deferred tax balances			86
Indefinite reinvestment assertion			$ (5)
Total income tax expense (benefit)	$ 345
Transition tax				$ 300
Re-measurement of deferred tax balances				78
Indefinite reinvestment assertion				(4)
Allocation of tax benefit from foreign tax credits				59
Total income tax expense (benefit)				$ 433