Description of Business, Including Segment and Geographic Area Information - Schedule of Property, Plant and Equipment by Geographic Area (Parenthetical) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Property, plant and equipment	$ 2,664	$ 2,512	$ 2,596
Philippines
Segment Reporting Information [Line Items]
Property, plant and equipment	$ 437	$ 412	$ 471