Fixed Assets - Summary of Fixed Assets (Detail) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property Plant And Equipment [Line Items]
Fixed assets gross	$ 37,813	$ 40,008
Less: Accumulated depreciation	26,237	27,187
Fixed assets less accumulated depreciation	11,576	12,821	$ 13,415
Land
Property Plant And Equipment [Line Items]
Fixed assets gross	428	479
Buildings & improvements
Property Plant And Equipment [Line Items]
Fixed assets gross	5,122	4,849
Machinery & equipment
Property Plant And Equipment [Line Items]
Fixed assets gross	32,160	33,834
Seismic vessels
Property Plant And Equipment [Line Items]
Fixed assets gross	$ 103	$ 846