Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Operating Loss Carryforwards [Line Items]
Effective tax rate (as a percent)	8.50%	4.60%
Benefit related to forecasted utilization of a 2020 NOL	$ 160
Valuation allowance	11		$ 11
Gross unrecognized tax benefits	34		39
Unrecognized tax benefits, net of federal tax benefits, that would affect the effective tax rate if recognized	16		17
Interest and penalties recognized in income tax provision	0	$ 0
Payable related to accrued interest and penalties	2		$ 2
State and local jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Deferred tax assets, loss carryforwards	$ 24