Income Taxes- Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2017
Unrecognized Tax Benefits [Line Items]
Tax Cuts and Jobs Act, Change in Tax Rate, Income Tax Expense (Benefit)	$ 160
Decrease in unrecognized tax benefits is reasonably possible		$ 79
Unrecognized tax benefits that would impact effective tax rate		28
Unrecognized tax benefits	251	255	$ 255
State and Local Jurisdiction
Unrecognized Tax Benefits [Line Items]
Unrecognized tax benefits	$ 29	$ 26