Income Taxes - Tax Cuts and Jobs Act ("Act") (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Statutory U.S. Federal tax rate (as a percent)		35.00%
Provisional amount recorded related to the remeasurement of the net deferred tax assets		$ 162
Provisional offset amount recorded related to the remeasurement of the net deferred tax assets		(162)
Benefit for the reduction of a deferred tax liability related to an indefinite lived intangible asset		11
Equity in the undistributed earnings of foreign subsidiaries for which income taxes had not been provided		2,300
Effect of subjecting undistributed earnings to the one-time transition tax		1,800
Provisional amount expected to be offset by available foreign tax credits		331
Provisional amount expected to be offset by available foreign tax credits primarily attributable to state taxes		$ 2
Forecast
Statutory U.S. Federal tax rate (as a percent)	21.00%