Property, Plant and Equipment - Components of Property, Plant and Equipment (Detail) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Construction in process	$ 595	$ 317
Property, plant and equipment	15,568	15,511
Pipeline equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	8,229	8,238
Offshore drilling equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	5,119	5,144
Other [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 1,625	$ 1,812