Segment Information - Financial Information by Major Geographic Area (Parenthetical) (Detail) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Property, plant and equipment, net	$ 16,192	$ 23,595	[1]
Norway
Segment Reporting Information [Line Items]
Property, plant and equipment, net		$ 3,893

[1] Of the total Europe, Property, plant and equipment (net), Norway represented $3,893 million in 2016.