Other Income (Expense), Net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Other Income and Expenses [Abstract]
Interest income	$ 12	$ 8
Adjustment to Deferred Compensation Expense	6	(6)	$ (11)
Net Foreign Currency Transaction Gains (Losses)	(7)	8	(41)
Equity income from investments in Trinidad	$ 2	$ 3	$ 4