Property, Plant and Equipment - Components of Property, Plant and Equipment (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Construction in process	$ 578	$ 1,927
Property, plant and equipment, net	15,611	13,524
Pipeline Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, net	7,491	7,062
Offshore Drilling Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, net	6,459	3,750
Other [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, net	$ 1,083	$ 785