Fair Value of Financial Instruments (Schedule of the Fair Value of Derivative Instruments in the Consolidated Balance Sheet) (Details) - Designated as Hedging Instrument [Member] - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Other Assets [Member]
Derivatives, Fair Value [Line Items]
Asset derivatives designated as hedging instruments	$ 3	$ 1
Other Long-term Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability derivatives designated as hedging instruments	$ 2	$ 18